3 Feb 2014

Dainton, “Sensing Change,” Summary

Corry Shores
[Search Blog Here. Index-tags are found on the bottom of the left column.]

[Central Entry Directory]

[The Dainton – Gallagher Phenomenal Time Debate, entry directory]

[Except for quotation, the following is summary. Unless otherwise noted, all underlining, boldface, and bracketed commentary are my own. Proofreading is incomplete, so mistakes are still currently present.]

Summary of


Barry Dainton

“Sensing Change”

Memory gives us data of the past, but sense seems to only tell us about the present. Thomas Reid writes:

It is by memory that we have an immediate knowledge of things past. The senses give us information of things only as they exist in the present moment; and this information, if it were not preserved by memory, would vanish instantly, and leave us as ignorant as if it had never been. (1855: 211) [Reid, T. 1855. Essays on the Intellectual Powers of Man. Ed. Walker. Derby: Boston.]

Memory plays a vital role in how we operate within time. Our actions at one moment, like going to the post office, might result from us remembering from before that we needed to go, and also remember from a while back the route to get there. In the short term, we would for example remember a bell chiming three times only be remembering the first two when the third strikes. But what about the immediate present? “Reid is right about all this. However, his claim that immediate experience is confined to the present is, on reflection, less innocuous that it might seem.” (Dainton 362)

Dainton now notes a strict or ‘proper’ conception of the present, which would regard it as a durationless instant. And since change requires duration, we would not in the present be able to perceive change.


Strictly (or properly) conceived, the present has no duration: it is simply the interface between what is future and what is past. Hence if our experience were confined to the present, it would be impossible for us to experience phenomena which require duration. More specifically, we would not be able | to directly experience change, succession or persistence. Reid draws just this conclusion [Dainton quoting Reid]:

. . . if we speak strictly and philosophically, no kind of succession can be an object of either the senses or of consciousness; because the operations of both are confined to the present point of time (1855: 235) [Dainton 361-362, quoting Reid, T. 1855. Essays on the Intellectual Powers of Man. Ed. Walker. Derby: Boston]

Yet, although this seems common sense, our everyday experiences tell us that we do directly experience succession in present moments of awareness. Reid thinks this only apparently so and that we are not really aware of succession in the present.

Aren’t there occasions (many of them) when we see a horse crossing a finishing line, or a car turning round a corner? Can’t we hear the explosive roar of a crowd, or the barking of a dog? Can’t we feel shivers running down our spine? Reid accepts that we do indeed often think and talk in these terms. He insists, however, that the apparent contradiction between strict philosophical truth and common sense (and common experience) is apparent rather than real [Dainton quoting Reid]:

. . . philosophers and the vulgar differ in the meaning they put upon what is called the present time, and are thereby led to made [sic] a different limit between sense and memory . . .. though in common language we speak with perfect propriety and truth when we say that we see a body move, and that motion is an object of sense, yet when as philosophers we distinguish accurately the province of sense from that of memory, we can no more see what is past, though but a moment ago, that we can remember what is present; so that philosophically speaking, it is only by the aid of memory that we discern motion, or any succession whatsoever. We see the present place of the body; we remember the successive advance it made to that place: the first can, then, only give us a conception of motion, when joined to the last. (1855: 236-7) [Dainton 363, quoting Reid, T. 1855. Essays on the Intellectual Powers of Man. Ed. Walker. Derby: Boston]

Dainton now wonders if Reid’s distinction between sense and memory really holds. For do we not actually perceive motion and change?

[…] a serious worry remains. How plausible is Reid’s proposed (precise, philosophical) delineation of the respective provinces of sense and memory? Motion certainly can be inferred in the way he describes, but can’t it also be perceived? If I move my hand towards my face aren’t I seeing my hand getting closer? Aren’t I seeing it moving closer? If I hear a fast succession of notes, played on a piano say, don’t I hear each note giving way to the next? Reid’s claim that we only ever see ‘the present place’ of a moving body—and so never actually see a body in motion—does not ring true.Might it not be that while Reid’s diagnosis does full justice to our temporal talk, it does not do full justice to our temporal experience? (363)

There are some philosophers who would agree that we experience change and passage in our temporal experiences. Russell says that “Succession is a relation which may hold between two parts of one sensation for instance between parts of a swift movement which is the object of one sensation. (1913: 65)” [Russell, B. 1913/1984. ‘On the Experience of Time’, in The Collected Papers of Bertrand Russell, vol. 7. London: Allen and Unwin., qtd in Dainton 364] Broad as well claims that we do not just see that something has moved or changed, but we we in fact see it moving or changing. “Broad remarked: ‘it is a notorious fact that we do not merely notice that something has moved or otherwise changed; we also often see something moving or changing. This happens if we look at the second-hand of a watch or look at a flickering flame. These are experiences of a quite unique kind; we could no more describe what we sense in them to a man who had never had such experiences than we could describe a red colour to a man born blind.’ (1923: 351)” [Broad, C.D. 1923. Scientific Thought. London: Routledge and Kegan Paul., qtd in Dainton 364]. Husserl also writes that we perceive succession while something is happening [and not after the fact in retrospect]. “In an auditory vein Husserl writes: ‘The evidence that consciousness of a tonal process, a melody, exhibits a succession even as I hear it is such as to make every doubt or denial appear senseless.’ (1964: 23)” [Husserl, E. 1964. The Phenomenology of Internal Time-Consciousness. (Tr. J. Churchill.) The Hague: Marinus Hijhoff., qtd in Dainton 364].

Dainton now examines empirical findings which support the claim that we perceive not states of things but their changes between states. It so far seems we do not have a sense organ for perceiving time, but there is research which suggests we have “perceptual sub-systems which specialize in the detection of motion.” (364) For example there is a part of our visual cortex that do not sensitive to color or shape but are highly sensitive to the motion of visible objects.

Empirical findings support these claims. If we possess a specific organ for the detection of time per se it has yet to be discovered, but we do possess perceptual sub-systems which specialize in the detection of motion. The area of the visual cortex known as V5 is one such: evidence suggests that the neurons in this region are insensitive to colour and shape, but highly attuned to large-scale motions, of the sort associated with medium-sized physical objects. Stroke-damage to this region in neurological subject ‘L.M.’ resulted in the onset of cerebral akinetopsia: the severely degraded ability to perceive motion (Zeki, 1991, 2004; Rizzo et al, 1995). Her predicament was characterized thus [Dainton quoting Zihl et al.]:

The visual disorder complained of by the patient was a loss of movement in all three dimensions. She had difficulty, for example, in pouring tea or coffee into a cup because the fluid appeared to be frozen, like a glacier. In addition, she could not stop pouring at the right time since she was unable to perceive the movement on the cup (or a pot) when the fluid rose. . . . In a room where more than two people were walking she felt very insecure and unwell, and usually left the room immediately, because ‘people were suddenly here or there but I have not seen them moving.’ (Zihl, von Cramon & Mai, 1983: 315) [Zihl, J., von Cramon, D. & Mai, N. 1983. Selective Disturbance of Movement Vision after Bilateral Brain Damage. Brain, 106: 313–340, qtd in Dainton 364].

[[Dainton is pointing to a perception sub-system which could be a candidate for what allows us to perceive time’s flow. I will here point out that change was perceived without flow, and it was done so with memory it seems. The subject does not say that people appeared suddenly here and there but suddenly here or there. In other words, they were not in two places in the same specious present. In each present, something occupies one location. How is that shocking? It also would not be shocking if in the just prior present she saw the object in a neighboring location. What is shocking is the difference between them, and that difference is given now as a phenomenon but it involves a memorial relation to what has just past. This example can in fact strongly support the model of time that Dainton does not advocate, the retentionalist model as he elsewhere calls it. It also allows us to further divide this phenomenon of flowing passage Dainton is here analyzing into two distinct phenomena: the phenomenon of passage and the phenomenon of flow. This woman perceives passage but not flow. If she did not perceive passage or change, then she would not be shocked by each new location of the moving objects. So the change of location is phenomenally given to her in each present moment. What is not given is the phenomenon of the motional and temporal flow between the changing positions of the objects. What this suggests is that the phenomenon of passage can be given without the direct perception of succession. And in terms of Dainton’s distinction between extensional and retentional models, what we might suggest instead is an intensional model. In this model phenomenal time is the result of the synthesis of before and after. To the degree that before and after are similar time in its extensivity is synthesized and the phenomenon of temporal flow is more evident. To the extent that before and after are dissimilar, time in its intensity is synthesized and the phenomenon of temporal passage or change is more apparent.]]

Dainton then turns to further empirical evidence which supports his claim that we directly perceive motion. There is something called the phi phenomenon, which is the pure phenomenon of motion without seeing something moving. Exner demonstrated it by showing two illuminated spots set at a distance from one another and flashed in succession. If flashed in succession very quickly, they appear simultaneous. If very slowly, they seem independent to one another. A little bit faster than that, it appears as if the one flash itself moves from one to the distant location. That case already exhibits the illusion of motion. But there is a very curious case that happens when the flashes are given just a bit slower than this optimal case. When at this slightly slowed speed, they go fast enough that they seem to be motionally connected but slow enough that no visual evidence illusory or not appears to connect their positions. Instead, the subjects perceive that there is motion between the flashes’ positions, but that motion itself is not visible. It is a pure phenomenon of motion. [[Wertheimer’s similar demonstration shows this also to not be a result of the persistence of vision. The marks are separated enough that the prior location does not superpose in overlap to the new one. And the flashes were too fast to be explained by eye motions that may have caught the prior flash, kept it as a persistent visual impression, then subsequently overlaid it with the new perception. So movement is perceptible without it resulting from the persistence of vision.]] This phenomenon explains why film strips can show us a succession of images but we perceive a fluid motion. [[Dainton is using this example it seems to make the point that we have sub-systems in our brain that perceive motion. It is not clear to me yet if this example also illustrates his point that the present must be extensive. So let’s consider the case of watching a film. The retentionalist would say that we only ever see a single image (or the flicker of black between), but we retain impressions of prior images showing the object in different but spatially continuous positions (continuous relative to the positions of other objects), which blur together to seem as though the position is continuously changing. The extensionalist would say that we perceive two images in one present but in their actual succession, and the phi phenomenon discerns the motional connection between them. And this is further supported by Wertheimer’s experiment which shows that it is not on account of superposed retentional images that we sense the motion of the image. However, the retentionalist could still say that motion results from the phi phenomenon, because our minds perceive the distant locations of the flashed object and discerns a motional connection between them. However, it seems Dainton might be making a different point, which is that motion itself is a phenomenon, and we directly in the present perceive an object’s motion and not retrospectively by means of processing memories and comparing them with the present. But the retentionalist might still claim that in any given instant we are impressed with the sense that something has moved, because right now we perceive in retentional memory both the prior and the current position; this proceeds over a series of moments, and thus during each moment we perceived motion.]]

Other findings point in the same direction. As the American psychologist Exner may have been the first to notice, if two brief visual stimuli are shown repeatedly in rapid succession—e.g., two illuminated spots on a screen a few inches apart, flashing on and off alternately—rather than seeing a succession of flashing spots, we see a single spot moving smoothly back and forth. The lesson? Our visual systems are not only capable of producing dynamic visual content, they are prepared to do so on the flimsiest of excuses. Perhaps we should not be surprised, for given the limitations of our optical systems, our eyes provide our brains with partial and fragmentary evidence of our surroundings, and our surroundings often contain objects that are in motion. | In any event, the effect is a happy one: substitute a rapid sequence of cinematic stills for the alternating spots—static images which depict a moving object at a succession of neighbouring locations—and the result is the clean, smooth motion apparent on cinema (and television) screens. Often called the phi phenomenon, this effect is also known as ‘illusory motion’. In one respect this is appropriate, given that our perceptual experience is dynamic whereas the images on the screen are static, but there is also a sense in which it is misleading: in most cases on-screen movements are indiscernible from the real thing. (Dainton 364-365)


So because this scientific evidence suggests we have the capacity to presently perceive motion and change, then we must reject Reid’s position that our consciousness never perceives directly outside a durationless present and instead take up the position that present consciousness occupies a specious present, meaning that we are somehow aware of an interval of time. (365) But there are very different ways to explain on what basis we are able to perceive this tiny interval of specious presence.

Dainton will proceed to explain his own model of specious presence, what he calls the Overlap Model, and he will argue for its advantages over the other models. “Although the Overlap Model has an agreeable simplicity, it can also achieve what more complex competing accounts fail to achieve: it can make sense of how our experience seems to be.” (365) But first he will address confusions and make some important distinctions.

§2 Conflations, Confusions, Etc.

There are not many who find it problematic to say that we perceive spatial extension. But many have argued that it is problematic to say that we perceive temporal extension. (365-366)

In the 15th chapter of his Principles of Psychology, James provides an account of time perception that has been influential but also misleading. (366)

We are trying to explain how we can be aware of an extent of present time. There are two main approaches to doing this. One says that consciousness itself spans a brief extensive temporal interval, and the other says that consciousness only seems to span an interval, but in actuality it does not. Each one accounts for temporal depth as though it ran along a different axis of co-givenness. The extensionalist approach thinks that the specious present is only given in an actual succession that is perceived directly and not by means of representations like memories, while the retentional approach thinks that the specious present is apprehended instantaneously by means of superposing in one instantaneous act of present awareness a series of retentions of prior moments all perceived simultaneously and together seeming to present to our awareness a thick present when in fact it is durationless in actuality. [[In the following quotation from which this summary is based, we find Dainton discussion a phenomenon that we might add to the phenomenon of passage and of flow. This would be the phenomenon of temporal depth, which is that time has a thickness to it. It would result from taking a succession together or distant moments together in the same act. One example of the phenomenon of temporal depth would be seeing a very young relative at one age and then again years later after they have grown up a good bit. In that moment, we do not merely sense the passage of the present or its flow, but also its depth, that there is content that stacks up and gives time a thickness.]]

When it comes to explaining how our awareness seemingly manages to extend through time there are two main schools of thought. Some maintain that consciousness itself spans a brief temporal interval; others maintain that although consciousness seems to embrace a brief temporal interval, it does not really do so. As the latter view is typically developed, the appearance of temporal depth is a consequence of a momentary cross-section of actual experience being apprehended together (and simultaneously) with representations of a temporal spread of phenomena. In the absence of any widely accepted labels for these approaches I will refer to them as follows:

The Retentional Model: a specious present consists of a combination of two simultaneously occurring ingredients: (i) a momentary direct experience and (ii) representations (or retentions) of the recent past.

The Extensional Model: individual specious presents consist of temporally extended episodes of experience that are apprehended as wholes. (Dainton 366)


Dainton. Sensing. fig 1


Fig.1 from p. 366 of Dainton, Barry (2008) "Sensing Change." Philosophical Issues, 18: 362-384.


In figure 1, Dainton provides a diagram showing how proponents of the retentional model regard the specious present as one instant within which are stacked other retained representations of prior moments and how those using an extensional model regard the specious present as occupying a small extent of ongoing present time. In the diagram, letters C and D stand for a short succession of heard tones. (366)

Dainton then gives a passages by James which can be seen as taking both approaches. (367) In one case, James writes that the present cannot be regarded as a knife-edge but rather as a saddle-back which straddles a breadth of time, or as James also calls it, a “duration-block”. James continues: “We do not first feel one end and then feel the other after it, and from the perception of the succession infer an interval of time between, but we seem to feel the interval of time as a whole, with its two ends embedded in it. (1890: 609–10)” [James, William 1890. The Principles of Psychology. New York: Dover, qtd in Dainton 367]. However there are a number of other passages where James portrays the present as exclusive to past and future [rather than including them a little in one present succession]. (367)

James’ lack of clarity on this issue allow for these dual interpretations, and other philosophers are likewise dually interpretable. (367)

There are also problems with James’ assessment of the length of the specious present, which he says is about 12 seconds and includes fringes lasting around a minute. However, if we tap our finger on the table at one second intervals, we do not still hear the prior one when the current one is sounding. (367-368)

When the specious present is construed as having a long duration that extends into future and past, this seems to suggest we can see the future and the past. But our normal perceptions do not allow us to do this. James offers an example of how such perceptions would imply we respond with certain behaviors, when in fact we never would.

Just suppose James’ estimates are along the right lines. Further suppose that you are about to embark on a timed 1500m run. Since you are eager to set a good time, you are straining to hear the starter’s gun; since you become perceptually aware (even if only dimly) of the sound of the gun around 30 seconds before it actually occurs, you could—if you were so inclined—get a half-minute head-start. Since the official at the finishing line will see you crossing the line 30 seconds before you actually do, you might easily find yourself taking up to a minute off the usual sort of time for a 1500m—and do so without even trying. (368)

[[We take special interest in this example, because it will be similar to another sort of example that might locate a problem with the extensionist overlap model. Instead of the runner, starting gun, and finish line, consider a bowling ball rolling to strike a set of pins. Dainton will suggest that the extensivity of the phenomenal specious present tells us about the temporality of the real world around us. So for Dainton, every present moment of the ball’s motion spans a short amount of time, across which the ball moves some extent of motion. Perceptually speaking we might think of this also in terms of the blur of the ball’s motion that we see. The ball in fact occupies a series of locations all in one singular present. Does that mean when it first strikes the pins that it does so not just from position of contact but also from prior distant positions? The problem we are raising with Dainton’s model and its implications for the real physical world are problems regarding how we account for causal relations between physical bodies. If we say that the distant location is less directly related causally to the impact, that it does not directly impact the pin but only indirectly by means of mediary moments, then what is the sense of including it in the present? What does it mean to say that a distant position of the ball is indirectly yet presently causally related to the collision of the ball? And also, if the extensive specious present has an order of succession and a direction of passage, that means there is a future-most part on one end and a past-most part on the back end. Does that not imply there is a present-most part in the center, relative to the ends? Dainton seems to imply such a thing in his finding the absurdity of a long extensive specious present. He says we might hear the sound 30 seconds before it actually occurs. This means it does not actually occur but it is still present. Now by extension consider Dainton’s much shorter specious present of less than a second. When the ball strikes the pins, does it somehow presently strike the pins before it actually strikes it? Is there any phenomenological evidence that we perceive things this way?]]

This example of the race comes from Plumer who tries to show that the sensory present construed as an interval leads to absurd conclusions. However, Dainton says that these conclusions do not actually result merely from the assumption that the present is extensional, because extensionalists do not need to claim that we see into the future and also extensionalists might better avoid these problems by saying that the specious present is only a second or so in length. Moreover, extensionalists still have the better account for how we directly perceive motion and change. (368-369)

Dainton then notes how some find the notion of the extensional specious present absurd, but this is because they mistake presence for simultaneity. Le Poidevin for example writes:

If we have a single experience of two items as being present, then, surely, we experience them as simultaneous. Suppose we are aware of A as preceding B, and of B as present. Can we be aware of A as anything other than past? (2007: 87) [Le Poidevin, R. 2007. The Images of Time. Oxford: Oxford University Press, qtd in Dainton 369]

So extensionalists must face the challenge of  accounting for successivity in a real present and retentionalists have the problem of explaining successivity in an instant. In the first case you have a temporal order that given singularly in the present, and in the second case you have a singular moment which contains an ordered succession. [Or perhaps: In the first case, you have the problem explaining how a multiplicity of successive moments can combine into a singular present, and in the second case you have the problem of explaining how a singular present can be seen as divided into a multiplicity of successive moments.]

It concerns the manner in which advocates of the specious present construe the relationship between (what we might term) presence and simultaneity. However, given that there are two fundamentally very different ways of conceiving of the specious present itself, there are two quite different worries in this connection. Extensionalists have the problem of explaining how it is that contents spread over an interval of ordinary clock time can appear successive if they also all seem present. Retentional theorists face no less of a challenge: according to them, the contents of the specious present are actually simultaneous (with regard to ordinary clock time), so how can it be that they appear successive? Or in slightly more formal guise:

Extensional Simultaneity Problem: how is it possible for contents which are (i) experienced together, and (ii) experienced as present, to be experienced as anything other than simultaneous?

Retentional Simultaneity Problem: how is it possible for a collection of contents which occur simultaneously to seem successive? (369, boldface is Dainton’s)

So one problem is accounting for how the parts of one specious present are combined. The other problem is explaining how different presents are put together to form the larger streams of our consciousness that run for very long periods of time.

We also need a plausible account of the manner in which distinct specious presents combine together to form continuous streams of consciousness. We can remain continually conscious for hours at a stretch, and generally speaking each neighbouring brief phase of our stream of consciousness slides seamlessly into its successor—our streams of consciousness are not divided into discrete pulses. (369).

So there are is an additional requirement that these models of the specious present need to satisfy.

The Dynamic Requirement: change, succession, movement, persistence are all directly experienced over short intervals.

The Continuity Requirement: specious presents must be able to combine to form a phenomenally continuous stream of consciousness. (370, boldface is Dainton’s)

[[We might think of these two requirements in terms of our distinction between the phenomenon of change or temporal passage and the phenomenon of flow. The model needs to explain how it is that we are directly aware of how in one specious present we can perceive motion or change, that is, how we can perceive succession within that present. It also needs to explain how many such presents flow continuously into one another to form a larger flowing stream of phenomenal time.]]


§3 Extensional Approaches

Dainton supplies figure 2 to put James’ “duration block” into extensional terms. The whole block P (the square) is one single specious present. It extends through time, as P is “a temporally extended phase of a stream of consciousness.” (370) Dainton. Sensing. fig 2

Fig.2 from p. 370 of Dainton, Barry (2008) "Sensing Change." Philosophical Issues, 18: 362-384.


Dainton then notes three things. 1) P’s contents, here depicted as the circle changing position, are “truly dynamic,”  because “they possess the character (familiar from our own experience) of a ball moving and falling.” 2) the phases of the movement are both successive (as the arrows serve to indicate) while at the same time “ these successive experienced phases are also parts of a single (extended) experience that is sensed as a whole.” They obtain their unity on account of the fact that they are “connected by the relationship of diachronic co-consciousness.” [Dainton 370]. 3) Although these phases of the object’s movement are perceived as successive, they are also “experienced as belonging to the sensory present: all parts of the movement (in this brief interval) are equally and vividly there in the manner typical of directly perceived phenomena.” (Dainton 370-371) [[Here we have Dainton defining presence in terms of contents having full vivacity]].

The dynamic requirement calls for an account for the direct perception of change, which this model fulfills: “since each phase of P is experienced as vividly present, change is presented in as immediate a way as it possibly could be.” (371)

If in this model presence was the same as simultaneity, then it would not be extensive. Presence instead should not mean a temporal location but instead it should be a phenomenal quality of the content. It is present because it appears in immediacy with the full vivacity of present things. In order to grasp how it is that within one extensive specious present all the phases can equally have the phenomenal quality of presence, Dainton has us think of pain sensations. When the pain sensation is occurring, it has phenomenal presence. A week later we can again have another pain that as well when happening will equally bear this phenomenon of presence. Dainton then reasons, if distant phenomena can have the have this phenomenal quality of presence to an equal extent, then of course two phases of the same pain can have have presence equally as well. [[Again it is unclear how to sharply distinguish Dainton’s concept of presence from the retentionalist’s concept of presentedness. Why could the retentionalist not say that whatever is perceived as present is either the content present in that instant or the retentional contents in the retentional background whose vivacity either equals the actively present one or whose vivacity is indiscernibly less vivacious? If our phenomenal evidence tells us that there is a specious present made up of a series of phases appear equally vivacious, could that not be evidence both for an extensionalist model where present contents are actually equally present as well for a retentionalist model whose immediate retentions whose vibrancy are either equal or differ indiscernibly? The only distinction I can see so far is that retentionalists say that the retentions diminish in vibrancy yet are still in the specious present where for Dainton the contents in the specious present do not diminish in vibrancy. But this could be explained by the fact that Dainton’s own phenomenological evidence tells him that there is not a diminishing trail after each immediate perception. A retentionalist might share this with Dainton and have a model where all retended contents in the specious present have equal vivacity even though they are not presently active.]]

But by ‘present’ the Extensional theorist means (or should mean) something else: not a temporal location but rather a phenomenal characteristic. Contents that are experienced ‘as present’ in the relevant sense possess what we might term phenomenal presence: they possess the immediacy and vivacity that are characteristic of all phenomenal properties as and when they occur. A pain sensation has phenomenal presence while it is actually being experienced; if at some future time it is remembered then this phenomenal presence is lacking—though of course memory-images have their own distinctive (but different and less vivid) phenomenal presence. There is nothing problematic in supposing that instantiations of phenomenal properties at different times can have presence in this sense—my headache last week had just as much phenomenal force and vivacity at the time as my current headache. Given this, to suppose that the successive phases of a single specious present can all possess phenomenal presence is not in the least puzzling or problematic either. (371)

So Dainton just explained how an extensionalist model can account for how the contents of the extensional specious present can be both really successive (and not simultaneous) while also being co-present: they all share an equal degree of appearing to be have the full force and vivacity of present things. [[Is this definition circular or problematically tautological? Q: What determines whether something is phenomenally present? A: Whether or not it has the properties of phenomenally present things. The only way I can make sense of this is if one phase in the succession within the specious present is ‘actually’ present or presently present and the others are no less present yet are more specifically pastly present and futurely present.]] [[Another problem with Dainton’s model might be that he still implies the distinction where the present contents are most vibrant and the non-present ones are less vibrant, just as in the retentional models based on presentedness. If what gives a content presence is that it has the full force and vivacity of presently perceived things, that means when they are not present they have less force and vivacity. Such non-present items would then have to be memories, as they are not present. Again, if retentionalists regard the most recent retentions as equally vibrant or indiscernibly less vibrant, then both models would be equally supported by phenomenological evidence.] Now Dainton will account for how these specious presents combine to form our stream of consciousness. He considers first one option, which lays out duration blocks end-to-end to form a continuous series, as depicted in figure 3.


Dainton. Sensing. fig 3

Fig.3 from p. 372 of Dainton, Barry (2008) "Sensing Change." Philosophical Issues, 18: 362-384.

That contents CD are combined in P1 and EF in P2 was already explained in terms of their sharing the full force of presence when they occurred [and presumably less when they form a memory that represents past experience.] But the combination of blocks CD and EF are not accounted for here. Dainton distinguishes succession of experiences from experience of succession. We experience CD as successive and EF as successive, because their successivity is given in their specious present. But what is lacking is the connection between D and E. Diachronic co-consciousness is a shared awareness of successive contents, and this is lacking between the blocks.

But if under the current hypothesis D and E do not fall within a single specious present they are not diachronically co-conscious, and so are not experienced as successive. From a phenomenal perspective, in the absence of any experiential connection between the two, they might as well belong to distinct subjects, or different universes. (371d)

To introduce this connection between blocks, what is needed is an intermediary block, P3, which is co-conscious of D and E.

Recognizing the existence of P3 does not bring with it a commitment to any new experiences (or phenomenal contents); we have the same four experienced tones as previously. All we are recognizing are additional phenomenal relationships among these experiences. Under the initial hypothesis only the pairings (C-D) and (E-F) were phenomenally unified; under the new hypothesis the pairing (D-E) is also phenomenally unified. Hence phenomenal continuity is secured at very little additional cost. (372)

This gives us the basic structure of the overlap model, in which successive specious presents are combined continuously by means of a continuous overlap of contents from one moment to the next. However, this model is an oversimplification of our actual experience. For one, the phases of our awareness are not as simple as merely hearing one tone and another as if each were a solid block. There is much more heterogeneous detail within the experiences of each tone. Nonetheless, richly complex phases are no less able to share common parts. “But this additional complexity does not affect the essentials: P1 could overlap with P3 by way of sharing a common part even if the parts in question possess highly complex and varied contents.” (372)

There is then a second issue to deal with. Dainton notes how in the simplified diagram the middle present overlaps the others by one half. He then says there is reason to believe that although the presents here are given a determinate length, that the do not move in such a disjointly segmented way that there is only exclusively one or another block. It would seem that the present moves in smaller steps. He depicts this in figure 4. (372)

Dainton. Sensing. fig 4

Fig.4 from p. 373 of Dainton, Barry (2008) "Sensing Change." Philosophical Issues, 18.

[His way of presenting this is not entirely clear to me. He says that “Isn’t the final third of C experienced with the third phase of E?” If each specious present keeps the same length, then even smaller increments would not allow for this. If we move P3 back a third (or have a P4 that is one third back) it would cover the final third of C but not the final third of E. And as the diagram already shows, the final third of E is not experienced with the final third of C, because the specious present is not long enough to do so. Perhaps he is suggesting something more dynamic, for example saying something like, ‘Does not the specious present move into the final third of E just while exiting the final third of C?’ Perhaps then the multiplying of smaller increments implies this more continuous motion.]

The overlap model will need to be developed, which would be done depending on one’s view of consciousness and it contents. So far we can say that the overlap model satisfies the continuity and the dynamic requirements. (373)

Dainton will examine another way for an extensionalist model to to treat individual specious presents. It is found more in retentional models and its merits will be evaluated. (373)

So far Dainton has assumed that the contents of duration-blocks all have equal phenomenal presence. Another view says that the contents presence diminishes the further they are from the present. To say that the contents diminish is to say that they are given under different modes of presentation. So Dainton distinguishes non-modal models, which say there is no change in presence, from model models, which say there is.

According to the alternative view, the contents within a single specious present systematically vary in the degree of presence they possess, with the more recent contents seeming more present (or less past) than earlier contents. James sometimes spoke in such terms, and Brentano was explicit about it: ‘only someone capable of a presenting with different modes and of a continuously changing mode of presentation can have a presentation of rest and motion, of continuing to exist or of proceeding in time.’4 (1988: 82) We can mark this difference thus:

Non-Modal Models: all parts of the specious present possess phenomenal presence to an equal degree; there are no temporal modes of presentation.

Modal Models: not all parts of the specious present possess phenomenal presence to the same degree; there are temporal modes of presentation. (373, Boldface is Dainton’s)


Dainton wonders if in fact our consciousness is even able to perceive such variations within a mere second. (374)



Dainton will now show why extensionalists should avoid taking this position. He shows the options for how they would do so in figure 5.



Dainton. Sensing. fig 5

Fig.5 from p. 374 of Dainton, Barry (2008) "Sensing Change." Philosophical Issues, 18.


In figure 5, the darker the regions, the greater the presence of the content.

As we can see, model A which strings the presents together portrays the quality of presence as varying in pulses, but that is unlike how we experience the present as being continuously fresh. So consider model B. Here each present overlaps a little with the prior one such that the freshest content of the prior moment is second fresh in the current, and so on within the span of the specious present. With this rendition we have the problem of lingering contents. Dainton thinks that contents do not lingering in our awareness like this model suggests. We should be able to hear E without C lingering in the retentional background, and if we wave our hands slowly in front of our eyes, it should not be the case that we see a trail behind it. [[Dainton also uses the moving hand example to also demonstrate the blur that can result, but it seems the difference has to do with speed. First note that in his “The Experience of Time and Change,” Dainton discusses how at a certain distance a moving train will appear as blur. In his talk “Passage in Experience and Reality,” at around 11.00 minutes or so, he discusses motion in visual experience. One sort are “objects which disappear into a blur (fast car, waving hand).” However, in his book The Stream of Consciousness he refers again to waving the hand, but in this case he seems to say he does not see a trail, and also he again says to move the hand slowly (skip to summarized pages 156 ff). So whether or not the moving hand makes a trail seems to result from the speed. But this will not help his argument, in fact it would seem to provide evidence against it. When it is moving quickly, it passes through very many more positions within the short span of the specious present. So perhaps as we move it slower, the trail contracts more and more around the hand, and at a certain decrease in the speed the trail is there but becomes indiscernible. Even if not, we have the problem of explaining the fasts moving hand without the trail being less vibrant than the hand, for else the specious present would have modal contents which it is not supposed to have. When I wave my hand quickly before my eyes, it is not as though it stretches from one place to the next. The trail behind the hand is not as vibrant. How does Dainton explain this? That trail appears within a specious present of the hand’s motion.]]

The problem now is with lingering contents. Note the way the content C in P1 continues to be perceived—albeit with gradually diminishing presence—in P2 and P3. If the contents of our consciousness were organized in this way then it would be impossible for us to hear a sequence of notes C-D-E without C still sounding when E is heard—but clearly, this is possible. In the case of vision, we would be unable to see objects move cleanly in the way that we do: if you were to move your hand slowly across your field of vision, you would invariably see it pursued by a ghostly contrail of fast-fading but still visible remnants of earlier perceptions. (374)

Dainton’s overlap model solves this problem because the specious presents share common parts. But if they are numerically identical in all cases, then they cannot have different phenomenal characters in each present. This is why they must be equally vibrant. [[But it might also lead to what we might call the problem of stretched contents. If the different positions of a moving object in one specious present are all equally vibrant, moving objects would appear as though they were being stretched spatially rather than moving from place to place]]

§4 Retentional Models

Those who take up the retentional model must explain our experience of change by means of these retentions [since change cannot be given in the instant of present awareness].

There can be modal and non-modal retentional models. Husserl’s retentional triangle can demonstrate.

Dainton. Sensing. fig 6

Fig.6 from p. 376 of Dainton, Barry (2008) "Sensing Change." Philosophical Issues, 18.


Horizontal line C-G is the experience of a single violin tone rising gradually in pitch [which each intervening letter being momentary phases of the consciousness of this change]. The virticle lines are each distinct specious presents, which are instantaneous and thus themselves are not long or deep enough to themselves be able to perceive any change. However, since they contain retentions going back a couple moments, we can nonetheless still in this model perceive changes that happen over extents of time.

Objectively speaking, each of these specious presents has zero (or minimal) duration; subjectively speaking, each possesses sufficient apparent temporal depth to manifest change and duration as it is immediately experienced. (376)

Retentional theorists often adopt the Model conception. In this diagram, that means points closes to the horizontal have the greatest amount of phenomenal presence, while as we move away from the horizontal line the contents diminish in presence and seem  more and more in the past. (376) The primal impression for Husserl is the most present moment. [In the next moment it becomes the most vibrant retentional content now pushed now vertically and] contents and phases of contents move gradually down into the retentional past at pace with the incoming present contents.

tone-phase D-E is experienced first as E-D* and then later as E*-D**: the same extended sound is thus experienced as sliding smoothly into the past. (376)

The lines extending above the horizontal are protentions. Broad does not have this in his model. (377)

Dainton will show that because the Retentional model encounters problems with the Dynamic requirement (explain passage) and Continuity requirements (explain flow) it is not a viable model. (377)

Non-modal retentional models fulfill the dynamic requirement because a spread of contents of equal presence is given retentionally. However it has the (Retentional) Simultaneity Problem: the model does not explain how simultaneous contents (of equal modality) can appear successive. Retentionalists can point out that it is not obvious that it is logically impossible for successive contents to be condensed [while maintaining their phenomenal traits of successivity]. We do not know enough about the relationship between the physical and the phenomenal in order to rule it out [because perhaps the physically successive can still somehow find its way into the phenomenon of successivity given in an instant.] Also, there is no guarantee that the property of consciousness as a vehicle will have the same property of its contents [so an act of awareness with the property of presence can contain contents somehow with the properties of succession.]

Here the (Retentional) Simultaneity Problem rears its head: how is it possible for a collection of contents which occur simultaneously to seem successive? By way of a reply, the Retentionalist can point out that if it is logically impossible for such contents to be temporally condensed, as it were, it is by no means obviously so. Do we know so much about the relationship between the phenomenal and the physical to be able to rule this out? Retentionalists (of both persuasions) can also argue that the divergence between the temporal properties of the contents carried by specious presents, and the specious presents themselves, is simply another manifestation of the widely recognized fact that there is no guarantee that the properties which feature in the content of a representation will also be possessed by the vehicle of a representation. (377)


So the non-modal retentional model might not necessarily suffer from the simultaneity problem. But it has another issue to deal with [in another case grouped with the problem of surplus contents. Here he considers it surplus-to-requirement, which elsewhere was about repeating contents.]. Each specious present when it is happening gives us a second of time through the retentions. So at C we seem to also hear B and A in our present. But at moments B and A we heard a second of sound. So there are two seconds of experience packed into one. And if the presents are divided into intermediary phases, this just multiplies the retained experience of time into a short brief experience of the present. This is not plausible. (377)

Because of these problems retentional theorists often advocate the modal approach, as for example was the case for Brentano, Husserl, and the later Broad. While solving these problems it confronts the theorists with “an awkward dilemma” (278).

On the one side of the dilemma, the danger is saying that retentions are like memory and lack the quality of presence. This then make it difficult to explain how retentional contents appear present to us when they also have the quality of memory or pastness. On the other side of the dilemma, the danger is to say that the retentional contents are all like present ones, then we have the problem of surplus contents [explained above when discussing non-modal models, which this would be close to]. “If at each instant we are aware of a second or more of immediately experienced change, we experience far more than we seem to” (378).

No retentionalist has been able to solve this problem (to Dainton’s knowledge) in a “clear and clearly satisfactory manner.” (378)

There is also the problem of fulfilling the continuity requirement. Each present is distinct, so how are they connected when none overlap?

Recall the example given earlier: if I hear an evenly spaced succession of tones that are of such a duration that only two can be experienced within a single specious present, I also hear each tone flowing into its successor. And what applies for individual tones applies equally to entire brief phases of our streams of consciousness. It may well be that there are relationship of causal dependency between one specious present and the next, but we are seeking | phenomenal relationships, which are something altogether different and more distinctive. (278-279)

[[If each moment is thought of like a differential, the tiniest possible partition of a change, then contained with it already is the link to the other moments.]]

The only way to satisfy the continuity requirement is to connect moments by diachronic co-consciousness. This can only result from the overlap model, but Dainton will consider if there is an alternative.

On reflection, it is difficult to see how the problem can be solved without allowing neighbouring specious presents to be connected by the relationship of diachronic co-consciousness. For unless we allow that the successive brief phases of our streams of consciousness are experienced together how are we to accommodate the phenomenological datum that these phases are phenomenally continuous? But anyone who takes this step is, in effect, abandoning the Retentional approach in favour of the Overlap form of Extensionalism. But is there any alternative? (279)

§5 Objections and Responses

Even though Dainton’s overlap model overcomes the other model’s problems, it has received criticism, and Dainton will examine those remarks. (379)

Sean Kelly for example finds three problems with the extensional approach. 1) How can we be perceptually aware of something no longer taking place? 2) How do we perceive duration directly? and 3) How can the overlap model explain continuity connections without retentions?

Regarding point 3, the overlap model has overlap by sharing common parts, and thus there is always continuity of consciousness. (379)

Regarding the second point, Kelly is skeptical that we can perceive intervals of time in themselves [like perceiving not just the contents of one second but perceiving that one second itself as if it could be experienced independently of its contents.] However, extensional theorist need not claim we have this ability. [[In Kelly’s “Temporal Awareness,” where he makes these objections, he writes, “In the first place, it is hard to understand how I could now be perceptually aware of something that is no longer taking place.” He considers as a possibility only that the time lag between an event and our perception of it allows for a perception of the past. But this is not what advocates of the specious present and specifically of the extensionalist model are saying. The more stubborn problem I think lies in how Dainton realizes he cannot have modal variation in the extensional specious present, but he is unable to formulate a model which explains passage without these valencies being implicit in the model’s structure. There are three phenomenal features of the specious present with regard to their temporal character that suggest the phases of one present carry with them a heterogeneity of temporal values. We will use some of Dainton’s own examples to help us locate some of these temporal features in our own experiences. And corresponding to these phenomenal features of our actual experience are structural features in Dainton’s overlap model which would explain the variance in modal values of speciously present phases even though Dainton insists these features are absent from his model.

Phenomenon 1: only one phase at a time appears to have direct causal influence on other present phases

Structural feature 1: strict linearity of the phases


Phenomenon 2: there appears to be a future-most and past-most part of each specious present.

Structural feature 2: on one side of the series are parts that have been carried over the most throughout a continuous progression of presents and on the other side are parts that have been carried over the least

Phenomenon 3: something in each moment feels fresh, new, original, and thus not-carried over from prior specious presents (by means of shared parts)

Structural feature 3: future-most phase has not appeared in any prior present. (From ABC to BCD, D is unique in that it is the only part that has been experienced for the first time.)

Before we look at how this temporal valency is found in our experience and in Dainton’s model, let first review the reasons why he says extensionalist models should not such modal variation in the phases’ temporal characters. In the A-model there was no overlap of presents but rather there were sequences of extensive presents each with their own phases but put into a chain. This portrayed time as though its freshness renewed in 1 second pulses, which we do not experience. In an overlap by superposition model (the ‘B-model’), there is the problem of lingering contents. (Although as a side note it is unclear how he explains the blur behind a fast moving hand or train if those are not lingering contents, and since there is a fuzzy blur and not stretch, it is apparent from our experiences that if there is lingering in the specious present then it is not contents that linger at full vibrancy. Nonetheless,) Dainton regards the lack of lingering contents to a slow moving hand to be evidence that we cannot have modal variation in an overlap by superposition model. The reason he cannot have it in an overlap by sharing common parts model is that the parts are numerically the same from moment to moment, which means that a phase that is fully present in one specious present and found in a succeeding one must also have the same phenomenal character. This is already called into question by the very phenomenological data Dainton puts forward in various cases, which we just mentioned parenthetically with regard to lingering contents. When speaking of his hand moving slowly within his vision, there is no trail behind it. But when it moves quickly, there is such a blur, just like how we see a blurry trail behind trains and automobiles moving at a certain speed. We see the train move a certain distance within a certain time. We do not see it stretch, just as something vibrating does not enlarge as if under magnification. The outlines might extend, but not at equal vibrancy, for otherwise we would see funhouse mirror-like distortions when things move rather than blurs. So somehow Dainton needs to explain some of his own examples using the overlap model. For now we will just take a couple of his examples, the fast-waving hand and speeding train. Why is it we see a blur behind the train and hand if phases of our awareness do not linger within the specious present? Whether he intends it nor not, his examples of fast moving objects do contain lingering contents, and he needs to explain why the blur is not the result of many positions of a moving object being perceived simultaneously with the most recent one as the most vibrant. But let’s for now just suppose that we see a succession of positions of an objects movement and put aside the question of whether older phases linger. He describes this as the directedness of the phenomenal flow of time, which in one diagram of the specious present he depicts as an arrow, and he writes: “The same three phenomenal presents are shown in the upper expansion, the single-headed arrows show the direction in which experience seems to be flowing, this apparent directedness is a consequence of the contents of the phenomenal presents; these contents have the form of temporal fields or spreads of content possessing inherent directedness or ‘flow’ (e.g. a ball moving to the right).” (Dainton “Time in Experience” p18d) Let’s continue with his assumption that the specious present is about a second or so long, and let’s imagine that we are watching the flow of motion of a ball moving to the right then striking a wall and bouncing backward to the left. There will be one specious present of our experience of this motion right when the ball strikes the wall, and since the specious present is about a second, let’s choose the specious present where the contact is made in the middle phase of the sequence, and including in our present awareness is it moving to the right and afterward to the left. Even though its rightward motion is equally present as the leftward movement, we do not perceive the rightward movement as being directly related causally to the leftward. When seeing any object moving one way we would not anticipate a sudden reversal in its motion unless we also perceived some other influence on its movement. So in our own experiences of present motion, we still seem to consider their being differences among the phases which makes certain ones appear most active and the others less active. Saying that we are mistaking presence with simultaneity does not remove this difference in value between active and inactive. If each phase has its turn at being active at the exclusion of the others, then each phase also has its turn at being inactive, and thus differing temporal values are given for each phase in each specious present. Whether or not we experience the less active parts of one present as having less presence in Dainton’s sense of full force and vivacity might be debatable. However, we still need Dainton to explain how a phase that is experienced as active seems just as present as the phases that are experienced as inactive (or how within one present the same phase has equally the phenomenal character both when it is taking its turn being active and also when some other phase has that turn instead). If it be argued that when we perceived the ball moving toward the wall we anticipated its reversal of motion and thus the activity of the forthcoming phase of the event was already given from the beginning, then imagine instead of the wall there is pane of glass that we were unable to see. Suddenly and inexplicably the ball changes direction. In that case there is really nothing about the older phase of the present experience which is indicative of the newer phase.

This sudden surprise of the ball’s reversed motion illustrates another modal difference in the phenomenal quality of the phases of one present. They are not only ordered in a strictly linear way but they are also ordered according to proximity to the past (memory) or future (the not yet experienced). Imagine Dainton’s melody example with this series of presents, each with three phases: ABC, BCD, CDE. By the third one, C will seem the oldest and past-most, if only because it is the most redundant part of that experience; it is the part that is most experienced in previous presents. There is a most stale and least stale part of each present of our experience. This is also found in the structure of Dainton’s model of the extensive present. The past-ward side has phases that have been around longer and their exit from the present will happen sooner. So perhaps Dainton could clarify how the fact that surprising new contents seem fresher than redundant older ones does not present within one specious present modal variation in the phases’ temporal qualities.

This is similar to the third temporally phenomenal feature in our experience of the specious present which is that each moment does not just seem relatively new but something about each moment is absolutely new and never before experienced. In the present when we first witness the ball reverse motion after hitting the glass, this reversal was nothing we experienced in previous presents. We see this in the structure of the model too, because each moment in the series ABC, BCD, CDE has a phase which was not found in the prior ones. Dainton also speaks of this newness or renewal that is a part of each present. “The fact that we directly experience both change and continuity suggests that contents spread over a brief interval of time can be co-conscious; the fact that our experience consists of a continuously renewed flow of content, a flow within experience itself, suggests that diachronic co-consciousness plays a key role in the generation of streams of consciousness”  (Dainton The Stream of Consciousness 2003, 114). Also recall how he writes of tapping a finger over and over. Despite each tap having very similar phenomenal traits with regard to their sonic qualities, instead of hearing the same tap, we hear a “new” tap. “Tap a table with your fingers, at a regular intervals of about a second; after each new tap, ask yourself if you can still hear its immediate predecessors.” (Dainton “Sensing Change” 367). So we ask again for Dainton to clarify his model so we can understand how it is that each present has a part that is absolutely new and unshared unlike the prior redundant phases and yet none of these parts are experienced as having modal variations in their temporal qualities.]] Kelly’s idea that we are seeing for example the past state of the star when we see its light here on earth does not change the fact that when we see it, it seems phenomenally present. But the question is, “How can a single experience, of a perceptual sort, include phases which seem anything other than fully present?” Retentionalists claim that earlier moments in the specious present are given as being past, but the non-modal extensional model says they are all experienced as having equal presence.

Retentionalists have an answer to this—the earlier phases are presented as past—but what has the Extensional theorist to offer? In fact, as I hope is clear, the non-Modal form of Extensionalism outlined in §3 has no difficulty here whatsoever. The earlier and later phases of a duration-block all appear equally present (they all see [sic] equally vivid), even though they are also experienced as a succession. (Dainton “Sensing Change” 380).

In the next paragraph, Dainton seems to suggest that his overlap model is more compatible with the theories of time used in contemporary physics and particularly in Einstein’s relativity theories. [[In another entry we examined parts of Dainton’s book Time and Space to see why he might think this is the case and also to what extent the overlap model is compatible with these theories in physics. What we concluded was that while these theories do understand time as extensive, like the overlap model does, they do not seem to consider there being a moving present of about a length of a second or so during which the phases or contents are present and those outside it are not present.]] Dainton writes:

Of course, anyone who believes that concrete reality is itself confined to what the present instant contains will find the Extensional approach problematic. If the past simply does not exist, contents located in the past cannot be co-conscious with contents located in the present. (This thought may well underlie the Retentionalist doctrine that only items that are momentary and simultaneous can be phenomenally unified.) But while this view of time—Presentism—may have some appeal at the level of commonsense, it does not sit easily with the four-dimensional space-time ontology that (many believe) Einstein’s theories of relativity require. By allowing phenomenal unity to connect contents that are separated by time as well as space, it is the Extensional approach that is more in tune with the findings of contemporary physics. (Dainton “Sensing Change” 380)


Dainton then wonders if the overlap model is compatible with findings in contemporary psychophysics. He looks at Grush’s ‘trajectory-estimation model.’ It is like Husserl’s tripartite structure of time consciousness: retention, intention, and protention. [Husserl also talks about retroactive repainting of retentions as new information comes in.] In Grush’s model our perceptual systems give us momentary updates of our environment.

In simple terms, Grush holds that our perceptual systems generate a continuously updated series of momentary representations of our environment. Each of these representations is a model of a subject’s environment over a brief interval— corresponding to the duration of the specious present—and in Husserlian fashion each model comprises three components: a representation of what is occurring at the present moment, a representation of the immediate past, together with anticipations of the immediate future. Since the data our perceptual systems receive from our sense-organs is often fragmented and ‘noisy’, these internal models usually embody a good deal of extrapolation and educated guesswork. As a consequence, as new data is forthcoming, the content of the models—the ‘story’ they tell of what is happening over a particular interval—may change accordingly. (380)

One thing in Grush’s model that is interesting for us here is backward masking. What happens most recently in a specious present can alter the appearance of what happened previously in that specious present. In the phi phenomenon, the second flash makes the first seem to move. Had there not been a second flash, the first would have appeared stationary. The second flash retroactively went back to the retended image of the first one and made it move to the location of the second.

Grush argues that the trajectory estimation model’s revisionary abilities allows it to make good sense of what is going on in a certain temporal | illusions. The relevant cases feature different forms of what is often called backward masking. Backward masking takes place when what is perceived as occurring over a brief interval (of up to a few hundred msec) is influenced, in often surprising ways, by what is perceived in the final phases of the interval. In the case of the phi phenomenon we encountered earlier, if a single flash of light A is followed, a short time later, by another flash B a short distance away, instead of perceiving a single flash at A and another at B, we perceive a single spot of light moving from the location of A to that of B; if the second flash doesn’t occur, we see only A, an immobile solitary flash. In such cases it seems, bizarrely, that later experiences can exert an influence on what is perceived prior to their occurrence. Applying the trajectory estimation model to the phi phenomenon, Grush suggests the following. Prior to the time at which data pertaining to the second flash reaches our perceptual systems, the latter work on the (reasonable) assumption that just one flash has occurred, and so only a single flash features in the internal models (or specious presents) that are generated up to that point. As soon as data pertaining to the second flash arrives, however, our perceptual systems revise their assessments as to the likely environmental causes of the incoming sensory data. Since the new assessment is ‘an object moving between the locations of A and B’ this is the content which features in subsequent specious presents. As for the earlier representations featuring a single motionless flash, these are immediately forgotten and play no further role. (380-381)

[Recall that the overlap model holds that contents remain numerically the same in different presents, so they would not be revisable it would seem.] Dainton notes that trying to account for this seemingly retroactive alteration in contents presents a problem for the overlap model.

If we try to make sense of the same case in Extensional terms we are forced to ascribe inconsistent contents to the same segment of experience, or so Grush maintains. To see why, consider how an Overlap theorist will interpret the phi phenomenon. We can focus on two overlapping specious presents: the first of these, S1, includes the initial seeing of the flash at A and what immediately precedes this; the second, S2, includes this flash at A and what immediately follows, which includes the seeing of the flash at B. Or more schematically, S1 = [. . .-A] and S2 = [A-B]. Now, if S1 and S2 overlap by sharing common parts, the shared part—in this case A—must have the same intrinsic phenomenal properties in each of S1 and S2. But in this case, this requirement is not met: in S1 the A-flash is motionless, whereas in S2 it is perceived as moving. Evidently, given this difference we cannot coherently hold that the final phase of S1 is numerically identical with the final phase of S2. The Overlap Model thus breaks down (see Grush, forthcoming, §5). [Dainton “Sensing Change” 381]

Dainton’s reply to this is that extensional theorists might hold that there is a processing delay. In the end this would mean that flash A is never perceived by itself. [[It would still seem to be the case that there is a specious present preceding the appearance of B when A also appears. Dainton seems to be saying that in this prior present, A is not perceived by itself, perhaps this is because it was too fast or because the next moment with B in it comes too fast, but still it is a bit unclear why it is that even with the delay there is not a moment with exclusively A in it.]]

We can agree that experiences cannot have inconsistent contents. But it would be wrong to suppose the Extensional theorist has no option but to interpret such cases in this way. Grush seems to be assuming that the contents featuring in Extensional specious presents reflect their environmental causes in an immediate and entirely unmediated manner. But there is no need for Extensionalists to embrace this view of the perceptual process. It is arguably more plausible to construe perceptual contents as representations that are generated in the brain only after a good deal of processing. This processing | makes for a delay—50-100 msec, say—but our brains put this to good use: they try to work out a single, coherent version of events on the basis of the fragmentary and (at times) conflicting data available to them. Only this ‘final draft’, as it were, reaches consciousness. Hence in the phi case, our perceptual systems reach the (in fact erroneous) conclusion that A is in fact a moving light, and this is the only way in which it features in our experience. While the initial solitary, static A-flash may well register in our perceptual systems, it does so only at a pre-conscious level. Since this flash in this form is not experienced, the problem of inconsistent perceptual contents does not arise. This way of construing matters is on display in the upper portion of Figure 7; Grush’s interpretation is shown in the lower part of the diagram. (281-282)


Dainton. Sensing. fig 7

Fig.7 from p. 382 of Dainton, Barry (2008) "Sensing Change." Philosophical Issues, 18.

Dainton continues by examining the flash-lag effect, which does not seem to pose a big challenge to the overlap theory but might need further consideration.

Dainton then concludes by noting “Time will tell which of these models most closely approximates the truth about these puzzling effects,” but there are at least three things we can say for sure at the moment. The first is that the doctrine of the specious present is not certainly untenable. The second is that psychophysical research might determine which models are correct but interpreting their results is not always straightforward. “The third and final lesson can be stated more succinctly: in the debates to come the Extensional approach may not hold all the aces, and it may not ultimately prevail, but it does at least start with several distinct and significant advantages” (383)




Barry Dainton (2008) “Sensing Change.” Philosophical Issues, 18: 362–384.

Barry Dainton. Stream of Consciousness: Unity and Continuity in Conscious Experience. London and New York: Routledge, 2000.

Notes from Barry Dainton’s Time and Space for comparison with his “Sensing Change”

by Corry Shores
[Search Blog Here. Index-tags are found on the bottom of the left column.]

[Central Entry Directory]

[The Dainton – Gallagher Phenomenal Time Debate, entry directory]

[All underlining, boldface, and bracketed commentary are my own. Proofreading is incomplete, so mistakes are still currently present.]

Notes from Barry Dainton’s

Time and Space

for comparison with his “Sensing Change”

In Barry Dainton’s article “Sensing Change,” he describes his overlap model of the specious present of our phenomenal awareness.

Of course, anyone who believes that concrete reality is itself confined to what the present instant contains will find the Extensional approach problematic. If the past simply does not exist, contents located in the past cannot be co-conscious with contents located in the present. (This thought may well underlie the Retentionalist doctrine that only items that are momentary and simultaneous can be phenomenally unified.) But while this view of time—Presentism—may have some appeal at the level of commonsense, it does not sit easily with the four-dimensional space-time ontology that (many believe) Einstein’s theories of relativity require. By allowing phenomenal unity to connect contents that are separated by time as well as space, it is the Extensional approach that is more in tune with the findings of contemporary physics. (Dainton “Sensing Change” 380)

Dainton writes more about the four-dimensional space-time view of temporality in his book Time and Space. What might be implied in this is that Dainton’s overlap model is also more in tune with contemporary physics because it is extensionalist. So we will see if his writings in Time and Space might determine this.

In the first chapter of Time and Space Dainton introduces McTaggart’s distinction between A- and B-series. The temporal character of events in the A-series are understood in terms of their relation to the now-moment from which we see them. This means that events are understood as being located either in the present now, or in the future that comes after the present now or the past that happened before the present. Events understood in terms of the B-series however are not seen as though there is a origin point which can make these distinctions. An event can come before or after, or be simultaneous with another, like how we think of historical events, but the temporal character of the B-series is not one that allows for present, future, and past. (TS 11)

Dainton then makes the following distinctions.

• The Block view: all times and events timelessly coexist, and all are equally real; temporal passage is unreal.

• The dynamic view: temporal passage is real, and time is not an ensemble of coexisting times and events. In short, the block-universe view is false.

• The tensed theory: A- concepts such as past, present and future have an essential and ineliminable role to play in any metaphysically adequate account of the nature of time.

• The tenseless theory: B- concepts such as earlier than, later than and simultaneous with are all we need for a metaphysically adequate account of time. (TS 11-12)

Because the overlap model is one in which the present ceaseless passes, it would seem to observe the dynamic view and not the block view. The question is then, does the contemporary physics that Dainton refers to here also take the dynamic view? In the overlap model, it is the present which is extended and passing. Do physicist think in the four-dimensional view that there is a one second long present that passes through time?

In the third chapter Dainton looks more closely at the four-dimensional ‘block’ view of time, which might be the view he says is popular in contemporary physics and required by Einstein’s relativity theories.

Beginning the first section, titled “Time without Passage,” he writes:

Many contemporary philosophers are convinced that McTaggart was essentially correct: our world is a block-like four-dimensional ensemble, lacking a moving present, wherein all times and events are equally real. (TS 27)

A bit later he writes:

Of all the models of time that we will be considering, the B-theory is currently the most popular among philosophers and physicists, but in many respects it is also the strangest and most counterintuitive. (TS 27)

In the fourth chapter he further claims that for B-theorists time does not really have a moving now that flows with time’s passage:

But if the B-theory is true, time is not going anywhere: there is no moving “now”, no slippage into the past, no crystallization from mere possibility into present actuality. (TS 44)

In chapter 5 he formulates a particular claim that in chapter 6 he critically examines:

The world is a four-dimensional ensemble, and all times and events are equally real and coexist. (TS 63)

In the 6th chapter he examines presentism, which he mentions in the paragraph we cited from “Sensing Change”. Presentism thinks that only the present is real. Here in Time and Space he says something similar:

Once one becomes aware of the Block view, and the scientific considerations (especially Einstein’s special theory of relativity) that can be mustered in its favour, denying reality to everything but the present can easily come to seem absurd. (TS 81)

In the 7th chapter Dainton examines the phenomenology of time. He begins first with phenomenological data of the phenomena of change and persistence.

Let us start by gathering some basic phenomenological data. Our typical experience is a combination of persistence and change. You are, let us suppose, lying in a deckchair gazing at the sky, where you can see a few white clouds moving very slowly against the unvarying blue backdrop. You see the occasional bird overhead. Sometimes they circle around for a while, and often they fly right on by. When you do see a bird in flight you are directly aware of its motion: the flapping of wings; the sometimes fast, sometimes slow changes of position. You are as fully and immediately aware of these movements and changes as you are of the unchanging blue of the sky. The same holds quite generally for other modes of consciousness. We see change, but we also hear it (a rapid sequence of notes played on a piano), feel it (slowly move your finger across the palm of your hand) and imagine it (recreate in your imagination the final shot in a tennis tournament – a ball goes out, a player leaps with joy, the crowd roars). In addition, there can be changes in what we smell and taste, and in our emotional state (a surge of anger). And then there is the inner soliloquy, the conversation we have with ourselves in thought, conducted sometimes in words, sometimes in images, sometimes in neither, which rarely ceases during our waking hours.

All this is obvious: consciousness is alive with change and variation. More elusive is the subtle but distinctive sort of dynamism that is characteristic of unchanging sensations. Return to the deckchair scenario. For some moments now you have been staring at an empty region of blue sky and nothing has changed. Your inner monologue has (if only briefly) ground to a halt, you have seen no movement, your visual field is filled with an unvarying expanse of blue. But is your consciousness entirely still or frozen? Have you come to a complete stop? No. Throughout this period you remain conscious, and conscious of the blue presence continuing on; you have a (dim, background, passive) awareness of the blue constantly being renewed from moment to moment. This passive awareness of continuation and renewal is perhaps more vivid in the case of auditory experience. Imagine hearing a sustained but unwavering note played on a cello: you hear a continuous and continuing flow of sound. This feature – call it “immanent phenomenal flow” – is possessed by all forms of experience (think of the burning sensation on the tongue caused by biting on a chilli pepper), and is a dynamic feature of experience that is independent of changes of the ordinary qualitative sort (the chilli- induced burning is felt as continuing on even when its intensity and qualitative character remains constant). Phenomenal flow is especially important in the case of easily overlooked but ever- present bodily experiences: the feeling of one’s limbs being disposed one way rather than another, the feeling of being vertical rather than horizontal or upside down, the feelings of pressure on one’s skin caused by clothes, seats, shoes and so on. When we are not moving about, our bodily experience is largely unvarying in quality, and so goes largely unnoticed, but it remains a constant – and constantly flowing – presence within our consciousness. (TS 104)

Thus we may distinguish two temporal phenomenal traits, passage (change) and flow (persistence):

• our experience of change is as direct and immediate as our experience of colour or shape;

• our experiences possess the feature of phenomenal flow. (TS 104)

Phenomenal flow, by the way, involves an awareness of the newness even of persistent things in our awareness:

As well as providing an explanation of how we can have an immediate experience of change, the model provides an account of phenomenal flow, the impression we have that a qualitatively unvarying sensation is continuously refreshed and renewed. (TS 110)

We also note that again Dainton in this book, like in other writings including “Sensing Change” claims that contents in his awareness do not linger.

If the two- dimensional model were true, we could expect that:

experiences would never end abruptly, they would always linger on for a short while as they are represented in successive awarenesses as possessing diminishing presentedness;

• at each moment we would be aware of our current experience together with a constantly shifting complex of representations of recent experiences, and so our consciousness would be choked with the residues of recent experiences.

But this is wrong on both counts. As far as I can tell, my consciousness is not clogged up with fading residues of prior experiences, and experiences do not always linger; they sometimes do end abruptly. It could be objected, “Ah, but the residues are very brief. That’s why you don’t notice them. Likewise, for the shifting constellations of representations.” This reply is unconvincing. If we cannot discern the posited representations, there is no reason to suppose that they have any phenomenological reality, and hence no reason to suppose that they contribute to our actual experience of change and persistence. (TS 111)

[[Dainton also at times refers to the blur behind a fast moving object. In cases when he mentions these he does not explain why these are not instances of lingering contents, and in cases when he says we never have lingering contents, he does not mention cases of blurred moving objects in order to clarify how they are not instances of lingering.]]

We also note here that in “Sensing Change” Dainton says that what is in the extensive specious present of his overlap model is present because it has the full force and vivacity of present things.

What quality, added to a pain sensation, would make that sensation seem to be in the past rather than in the present? If I am now experiencing some sensation, won’t the experience seem to be occurring now irrespective of any peculiar qualities it might possess? Someone might say, “Presentedness is not an additional property that experiences have. It is akin to Hume’s ‘force and vivacity’. It is simply a measure of the intensity of an experience; as experiences lose presentedness they become progressively fainter, until they fade away altogether.” But this won’t work. Do some parts of the image in Figure 7.5 appear “more past” than others? [This figure shows a star-shaped image of light where the center is bright and diminishes toward the edges](112)

[[But when discussing non-extensional models, he examine a similar concept called presentedness, which is a quality that retentional contents have to diminishing degrees as they move further away from the present toward the past. He says that presentedness cannot be understood as Hume’s full force and vibrancy, because presently given weak phenomena like faint sounds or light do not now sound as if in the past. Those advocating for a diminishing presentedness might say that what makes the content seem more past is not merely its faintness as much as how much fainter it is from when it first presented itself. The faint sound now gets even fainter and as it does, and only as it does, it appears less and less present. It is also unclear how it is that Dainton’s criticism of presentedness does not apply to his concept of presence which is defined in exactly the same terms as presentedness. If a sound is currently very faint, does it seem less present than other concurrent sounds which are prominent? If not, how exactly do we make a clear distinction between presentness and presence with respect to currently faint phenomena?]]

When describing his overlap model, he explains how contents separated by others are not transitively co-conscious, and he also says that the specious present is less than a second.

Since the specious present is of limited duration (probably less than a second), the relationship of co- consciousness over time (diachronic co- consciousness) cannot be transitive. (114)

Later there is a paragraph which might help us better understand how the features of the overlap model might be in tune or not in tune with the contemporary physics understanding of time. It is not here clear if he is saying that moments outside the present are real in the same way as those inside the specious present. He only says that they are real in the present, but he puts in it a way that might suggest we cannot say something about the reality of those outside it.

However, in assessing the plausibility of what is being offered here, we must not lose sight of the model of time with which we are dealing. The overlap theory tells us that for me to experience C flowing into D, or D flowing into E, my experiencing of C must be co-conscious with my experiencing of D, and my experiencing of D must similarly be co-conscious with my experiencing of E. When two experiences are (diachronically) co-conscious, they are experienced together, in a unified temporally extended episode of experiencing. It is difficult to see how C could be related to D in this way if C is unreal when D occurs – and similarly for D and E. In order for C and D to be part of one unified experience, C and D must surely coexist. But according to the Dynamic Presentist, since C and D occur in succession, they do not coexist. (118)

[[A presentist might also say that to perceive C flowing into D is to perceive the passage between and thus to have both simultaneously in consciousness in that instant of their passage.]]

[[More generally speaking, it is not clear if the overlap model assumes time makes up a B-series, because the present has an extensive structure where successive moments co-exist, or if because the present is always in motion that it makes it not a B-series. If it is not a B-series on account of the movement of the present, then it is unclear how it is compatible with contemporary theories of physics which seem to construe time as B-series.]

Then he specifically addresses the question of whether the overlap model is compatible with other metaphysically intelligible views of time, and he says that it is “neutral” with respect to them. First he looks at the block view, which is like the B-series conception. All moments have their place, none are present, and there is no flowing now. But the way he describes it here suggests that within the four-dimensional block a stream of consciousness is like a small part that is only aware of tiny moving portion of it. It does not explain the relationship between the movement of the stream of consciousness and the non-movement of the block. So he explains why it is that the specious present is only a small part of the whole block, but he does not explain why in the block a small part of it is moving.

What of the other models of time that we have considered and found metaphysically intelligible? For better or worse, the overlap theory seems entirely neutral with respect to these.

Consider the Block view. The overlap theory tells us that co-consciousness extends over short periods to create temporally extended “phenomenal presents”, that successive phenomenal presents overlap, and that the contents of these phenomenal presents have an inherent dynamic character. That our experience is structured in this way guarantees that we will have the impression that our consciousness is confined to a forward-moving present even if, in reality, past and future experiences are just as real as present ones. From the four-dimensional perspective, a stream of consciousness is akin to a glowing filament embedded in a long glass block; the filament is aglow throughout its entire length, but this is not discernible to the subject of these experience, who is only ever aware of those tiny stretches of experience joined by co-consciousness. (119)

Dainton contrasts his overlap theory to ones which conceive of the present as durationless. He claims that such models cannot account for the phenomenon of passage. But one argument against Dainton’s position, which he does not address, is that physics understands an instant of motion as being like the smallest part of passage. In one sense it is durationless in that it is not an extent of time, but it is not the same as a lack of temporality. It in a way is greater than a zero amount of time and less than any givable finite amount of time. At any such instant of motion, we can calculate the instantaneous velocity of the motion. In a sense, the object is both in motion and at rest. It is at rest because it does not travel any extent of space or occupy any extent of time, however it is in motion because it is still in passage between locations, and thus it can have a certain rate of making that passage even though no extend of time or space transpires. Dainton in fact discusses and describe this operation in physics, and he even notes that modern scientific and technological calculations depend on it. This suggests that the instantaneous view of parts of motion are compatible with contemporary views of time in physics. What is interesting is that he does not consider this view of the instant when examining possible models of time consciousness where the present is instantaneous. Could not the present in our phenomenal consciousness be an instant which is aware off the smallest part of change? He explains instantaneous velocity when discussing the at-at account of motion, which can solve Zeno’s paradox of the arrow. An arrow in flight occupies a series of points in space coordinated to instants in time where it is found at those locations. But it is not at motion in any of the points, so it is never at any point or moment in flight. Dainton explains how those who think time and space are continuous can reply that since the arrow was at a different location prior to any in its motion, then it is changing location across time and thus is in movement. It is at certain points at certain times, and at intermediate points between them. He then looks at the calculus way of looking at this to show how even in the instant the arrow would have an instantaneous velocity, which suggests that no matter how small of a part of its motion we look at, it is at motion in that instant.

17.1 The “Arrow”

Imagine an arrow in flight. At every instant during its flight, the arrow is at some specific location, occupying a volume of space that corresponds exactly to the arrow’s own size. Since instants are durationless, and motion takes time, the arrow is not in motion at (or during) these instants. Yet the arrow’s entire flight is composed of these instants, and nothing but these instants. If the arrow is not in motion at any of the instants that jointly make up its flight, it is not in motion at all.

This is Zeno’s “Arrow” paradox. The reasoning obviously generalizes – what holds for the arrow holds for any object in motion – and so if the argument is sound, motion does not and cannot occur. The argument is sometimes taken as being directed – along with “Stadium”, which we will be looking at shortly – against the doctrine that space and time are discrete, rather than continuous. While this may well be true for the Stadium, it is not obviously true in the case of the Arrow. In any event, the Arrow reasoning certainly poses a significant problem for those who believe space and time are continuous rather than discrete, the conception of the continuum with which we are currently concerned. If space and time are composed of dimensionless points, and the arrow’s flight involves its occupying a continuous succession of different locations, we are undeniably confronted with the problem of explaining how it is possible for the arrow to have moved, given that it is not (seemingly) moving during any of the momentary stages which constitute its flight.

The at-at theory

Those who subscribe to the orthodox conception of the continuum have a response to the Arrow challenge that is widely, although by no means universally, accepted as adequate. The proposal runs as follows. Whether or not an object is in motion at a given time t does not depend on the object’s condition or state at time t. Rather, it depends on how the object behaves at those temporal instants neighbouring t. If at these neighbouring times the object is at precisely the same location as it is at t, then we say that it is not moving at t; but if it is at different locations, then we say that it is moving at t. Since everyone can agree that an object is moving if it is changing its location over time, this simple account seems to give us all we might want. Or as Russell puts it, “Motion consists merely in the fact that bodies are sometimes in one place and sometimes in another, and that they are | at intermediate places at intermediate times” (1917: 84) [Russell, B. 1917. “Mathematics and Metaphysicians”. In his Mysticism and Logic. London: George Allen & Unwin]; hence the “at-at” label for this view.

It will be useful to take a closer look at what proponents of the at-at account are proposing. Suppose we start with an interval I1, running from half a second before t to half a second after t (see Figure 17.1). We calculate the arrow’s average velocity over I1 by dividing the distance travelled over the course of this interval by the time taken, which in this case is one second. This gives us an initial, reasonably accurate, approximation of the object’s velocity at t. To get more accurate approximation we repeat the procedure for a shorter interval I2, which is also centred on t, but running (we can suppose) from a quarter of a second before it to a quarter of a second after it. By working out the average velocities over shorter and shorter t-centred intervals we will generate increasingly accurate estimates of our object’s velocity at t itself. In standard fashion we now introduce the limit-value of the series at t: it is the average velocity to which the series of ever-decreasing intervals converges as the end-points of the intervals approach arbitrarily close to t itself. We can now stipulate that our object’s instantaneous velocity at t is simply this limit-value.

This procedure can be applied quite generally to deliver the instantaneous velocities of any moving object at any time. Indeed, the procedure just outlined is essentially that used in the calculus, where velocity is the “first derivative” of change of position with respect to time (acceleration, the rate of change of velocity, is the “second derivative”). Since the day of Newton and Leibniz, calculus has been at the heart of physics and applied mathematics, and it is undeniable that much of the success of the former is due to the latter; without the methods of the calculus we would not be able to calculate the rates of change of interdependent quantities in the precise and accurate ways our science and technology require. (TS 289-290)

Dainton. Time and Space fig17.1

Figure 17.1 from page 290 of Barry Dainton's Time and Space (2010 2d ed)

As we can see, time is understood here as an extension, and this is specifically Dainton’s claim, that contemporary theories in physics regard time as extensive in their four-dimensional models. Our question is whether or not the overlap model’s other features are compatible with this four-dimensional view. We might for example wonder, do these contemporary conceptions of time think that within the extent of time there is a one second long moving present? One way Dainton might locate something like this in Einstein’s special relativity theory is in how there is no absolute simultaneity. Events that in one frame seem simultaneous might in another seem successive.

In the context of STR, simultaneity is not absolute but frame-relative. Spatially separated events that are simultaneous from the perspective of one inertial frame are not simultaneous from the perspective of other inertial frames, and since the perspectives of all inertial frames are equally valid, there is no sense in the idea that the events in question are “really” simultaneous or not. (TS 322)

So the present cannot be seen as an instant that all frames share. So we consider all possible observations. In one such comparison, there will be events that in one frame seem simultaneous and in another seem successive, and we are looking at the pairing where magnitude of the extent of time in the succession of events is greatest for any other comparison of frames. This difference in magnitude would be the extensive present, because it is the extent of time during which all other observations fit the same events. So while in the frame where the events seem maximally successive, in another they are simultaneous. The presence in the simultaneous case is extensively stretched in the successive case, and this is the extent of the present. This brings us closer to seeing how the extensive overlap model might be closer to contemporary physics and Einstein’s relativity in particular, but there is still a lot that is not clear about this account. Does that mean that because our specious present is one second long, this extent of time is the greatest possible temporal difference between all frames in the universe? And are we suggesting that when we view the specious present we are somehow perceptive of the temporally difference between reference frames of which we are not otherwise perceptively aware of? Perhaps, but Dainton does not clarity if and how this might be so.

When discussing general relativity, Dainton more specifically addresses when it is compatible with B-series conceptions of time and dynamic conceptions of time. He writes that “Nothing in GTR is obviously incompatible with the Block conception;” (381) and “A certain class of GTR models are surprisingly friendly to those versions of dynamism that posit a universe-wide tide of becoming” (TS 381). However, in this section Dainton does not clarify whether or not in any version of relativity theory that there is a moving extensive present of a second or so in duration.

Thus at least in his book Time and Space, Dainton does not give us reason to think that all the important features of the overlap model of the specious present [the present is an extent of time of about one second long where all phases or contents of that present are equally present with those outside its scope being past and future] correspond with the features of time as conceived in contemporary physics and in particular in Einstein’s relativity theories. The main point of difference would be that while both see time as extensive, it is unclear if physical theories think there is a moving present of a length of about one second long. We recall how Dainton writes in “Sensing Change:”

But while this view of time—Presentism—may have some appeal at the level of commonsense, it does not sit easily with the four-dimensional space-time ontology that (many believe) Einstein’s theories of relativity require. By allowing phenomenal unity to connect contents that are separated by time as well as space, it is the Extensional approach that is more in tune with the findings of contemporary physics. (Dainton “Sensing Change” 380)

It seems that while extensional approaches in general are compatible with the way that contemporary theories of physics portray time as being part of a four-dimensional space-time manifold, the overlap model of the specious present as a specific extensional model of time does not correspond with the way that contemporary physics understands the ‘present’ within the extent of space-time. Thus unless Dainton can maker further clarification, it does not seem safe to claim that his overlap model is compatible with contemporary theories of time in physics.

Works cited:

Barry Dainton. (2010, 2nd edition [1st edition 2001]) Time and Space. Durham: Acumen.

Barry Dainton (2008) “Sensing Change.” Philosophical Issues, 18: 362–384.