Showing posts with label Aristotle. Show all posts
Showing posts with label Aristotle. Show all posts

24 Jul 2021

Quine (1) “Two Dogmas of Empiricism”, section 1, “Background for Anayticity”, summary

 

by Corry Shores

 

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[The following is a paragraph by paragraph summary of the text. More analysis is still needed and will be updated when conducted. Proofreading is incomplete, so please forgive all my various mistakes. Material between brackets or between parentheses within brackets is my own and should not be trusted over the quotations, which themselves may contain typographical errors from their transcription. Please consult the original text in any case.]

 

 

 

 

Summary of

 

W. V. Quine

 

“Two Dogmas of Empiricism”

 

 

1

“Background for Anayticity”

 

 

 

 

 

 

 

 

 

Brief summary (collecting those below):

(1.1) There are forerunners to Kant’s analytic/synthetic judgment distinction. {1a} Hume’s relations of ideas, which are logically certain (because their contraries imply contradictions), as for example mathematical equations, and {1b} matters of fact, which are probable, because their contraries are not contradictions, as for example ‘the sun will rise tomorrow’. (Enquiry 4.2) {2a}  Leibniz’ truths of reason, which are necessary because their opposite is impossible, and {2b} truths of fact, which are contingent, because their opposite is possible. (Monadology 33, Philosophical Texts p.272) Morton White shows that the definition of analyticity as “Analytic statements are those whose denials are self-contradictory” is insufficient, because there are cases of denials that render contradictions, but it is not a syntactical case of “A and not-A;” for instance “All men are rational animals” would be denied as “It is not the case that all men are rational animals” (or “Some men are not rational animals”). (1.2) For Kant, an analytic statement is one that “attributes to its subject no more than is already conceptually contained in the subject. (20) Quine notes two problems with this definition: {1} it is limited only to statements in a subject-predicate form (and presumably there are analytic statements not of this form, but Quine does not mention any here) and {2} its notion of containment remains only at a metaphysical level (perhaps because it is not defined formally). Quine sees Kant’s intent and redefines Kant’s analyticity as “a statement is analytic when it is true by virtue of meanings and independently of fact.” (21) We turn now to the notion of meaning used here. (1.3) Meaning cannot be mere reference, because there are cases where two different names name the same thing, but each name has a different meaning, as for instance Frege’s ‘Evening Star = Morning Star’. As the two names are not identical in meaning, this statement is not analytic. (In fact, the meaning of ‘the evening star’ is almost the opposite of the meaning of ‘morning star’.) Also the identity made between the two is a statement of fact that is demonstrated through astronomical observation. (Thus it does not fulfill either of the Kantian requirements that an analytic statement be “true by virtue of meanings and independently of fact.”). (1.4) Another example of a case where equated names do not render an analytic statement is Russell’s “Scott is the author of Waverley.” (1.5) Even with abstract terms, like number values,  we still have this problem, as “9” and “the number of planets” names one and the same abstract entity (the number value of nine), but the equation of the two is not analytic; for, observation was needed to make that equation, and a reflection on their meanings is insufficient to. (1.6) A general term or predicate does not name an entity, but it is true of an entity or entities, or of none. The extension of a general term is that class of all entities that a general term is true of. With singular terms, we distinguished its meaning from its extension (Evening Star and Morning Star have the same extension, the planet Venus, but different meanings); similarly, we must do the same for general terms. So for example, the general terms “creature with a heart” and “creature with a kidney” may have an identical extension (supposing all creatures with the one organ also in fact have the other), but they are not alike in meaning. (1.7) We sometimes contrast intension (or meaning) and connotation with extension or denotation. (1.8) Aristotle’s notion of essence was a forerunner for what we now call intension (meaning). Aristotle distinguishes the essential from the accidental, so for humans, it is essential to be rational, but it is accidental to have two legs. Quine notes a problem. Consider a human person. They will be both rational and two-legged. Quine observes however that we may classify this person either as a human or a biped. Insofar as they are a human, their rationality is essential and their bipedalism is not. But insofar as they are a biped, their two-leggedness is essential and their rationality is not. (Here Quine claims that we are dealing with meanings rather than essences. We might say under a doctrine of essences that for some particular individual person, their rationality is essential and their bipedalism is not. However, under a doctrine of meanings, for this individual’s predicates of being rational and bipedal, it cannot be said that one of them is essential and the other is not. For, by the same reasoning that we would use to designate one over the other, we may equally use it to designate the other over the first. (We might say, “here is a human,” and take their rationality as essential; or, for the same person, we might say, “here is a biped” and take their two-leggedness as essential. This is because in that case we are concerned with meanings (of “human” and of “biped”) rather than with the entity itself’s proper essence).) “Things had essences, for Aristotle, but only linguistic forms have meanings. Meaning is what essence becomes when it is divorced from the object of reference and wedded to the word.” (22) (1.9) In a theory of meaning, we would need to explain what kind of objects meanings are. They seem to be ideas. For semanticists, they are mental ideas. For others, they are Platonic ideas. But these characterizations are not sufficient because such entities are too elusive to erect “a fruitful science about them.” (22) Some things are often not clear about such entities: {1} whether we have two or one; and {2} when linguistic forms are synonymous or not. (1.10) But once we distinguish a theory of meaning from a theory of reference, we can then think of meanings just in terms of synonymy of linguistic forms and the analyticity of statements. (1.11) We began wondering how to define analyticity. (We saw in the Kantian conception that it can be understood as being true by meanings and independently of fact. See 1.2. We distinguished meaning from extension. Then we found that meanings are hard to define and unnecessary when we have extension.) We now no longer consider a “special realm of entities called meanings.” (23) That means we must find other ways to understand analyticity. (1.12) Statements that are often considered analytic in philosophy are generally of two types. {1} Ones that are logically true, for instance (1) No unmarried man is married. (This is true no matter what the interpretations are of the terms. It is formally true.) (1.13) {2} The other kind of analytic statements are ones that can be rendered into a logically true format by substituting synonyms. For example, (2) “No bachelor is married” can be rendered “No unmarried man is married” but substituting the synonyms “bachelor” and “unmarried man”. Yet, we do not have a proper (formal?) characterization of these kinds of analytic statements, especially since we do not have a (formal?) definition of synonymy. Thus we do not have an adequate (formal?) characterization of analyticity. (1.14) Carnap defines analyticity in the following way. We begin by assigning all the truth values to every atomic statement in a language. Each complete combination of assignments for all the atomic sentences is what he calls a “state description.” We can then compositionally build up the complex statements of the language using logical means, with their truth values being computable based on logical laws. A statement is analytic when it is true under every state description. Since a state description is like a possible world (it is one combination of facts), this can be seen as following Leibniz’ notion of being true in all possible worlds. (Quine then explains a problem with this conception: if the language has extralogical synonym-pairs, such as ‘bachelor’ and ‘unmarried man’, then statements like “All bachelors are married” will turn out to be synthetic rather than analytic. Thus) “The criterion in terms of state-descriptions is a reconstruction at best of logical truth.” (24) (1.15) Yet, Carnap’s main concern was clarifying probability and induction, not analyticity, which is our concern, “and here the major difficulty lies not in the first class of analytic statements, the logical truths, but rather in the second class, which depends on the notion of synonymy.” (23)

 

 

 

 

 

Contents

 

1.1

[Forerunners of Kant’s Analytic/Synthetic Distinction in Hume and Leibniz. M. White’s Account for the Inadequacy of Defining Analyticity as Denial Rendering a Contradiction]

 

1.2

[Reformulation Kant’s Notion of Analyticity as Being True by its Meanings and Independently of Fact]

 

1.3

[Meaning as Not Referential Naming]

 

1.4

[Russell’s “Author of Waverley” as Another Example of an Identifying Naming Statement That Is Not Analytical]

 

1.5

[Abstract Terms as Also Having This Problem (“9” and “The Number of Planets”)]

 

1.6

[Meaning and Extension for General Terms (“Creature with a Heart” and “Creature with a Kidney”]

 

1.7

[Intention (Meaning)/Connotation Vs. Extension/Denotation]

 

1.8

[Aristotle’s Essence as Being Similar to Meaning, but Not Identical]

 

1.9

[Difficulty in Defining What Kind of Entities Meanings Are]

 

1.10

[Defining Meaning as Superfluous]

 

1.12

[Logically True Analytic Statements]

 

1.13

[Statements Made Logically True by Substitutions]

 

1.14

[Carnap’s Definition of Logical Truths (Analyticity)]

 

1.15

[Turning Instead to Analyticity From Synonymy]

 

Bibliography

 

 

 

 

 

 

 

Summary

 

1.1

[Forerunners of Kant’s Analytic/Synthetic Distinction in Hume and Leibniz. M. White’s Account for the Inadequacy of Defining Analyticity as Denial Rendering a Contradiction]

 

[There are forerunners to Kant’s analytic/synthetic judgment distinction. {1a} Hume’s relations of ideas, which are logically certain (because their contraries imply contradictions), as for example mathematical equations, and {1b} matters of fact, which are probable, because their contraries are not contradictions, as for example ‘the sun will rise tomorrow’. (Enquiry 4.2) {2a}  Leibniz’ truths of reason, which are necessary because their opposite is impossible, and {2b} truths of fact, which are contingent, because their opposite is possible. (Monadology 33, Philosophical Texts p.272) Morton White shows that the definition of analyticity as “Analytic statements are those whose denials are self-contradictory” is insufficient, because there are cases of denials that render contradictions, but it is not a syntactical case of “A and not-A;” for instance “All men are rational animals” would be denied as “It is not the case that all men are rational animals” (or “Some men are not rational animals”).]

 

[We are dealing with the first dogma (see section 0.1), which is that truths are distinctly either: {1a} synthetic, meaning that they they are grounded in fact, or they are {1b} analytic, meaning that they grounded in meanings independently of matters of fact. Hume made the distinction between relations of ideas and matters of fact (recall from his Enquiry concerning Human Nature, Section 4, part 2 that we have knowledge either of {1} relations of ideas, which are logically certain (because their contraries imply contradictions), as for example mathematical equations, or we have knowledge of {2} matters of fact, which are probable, because their contraries are not contradictions, as for example ‘the sun will rise tomorrow’ (for, it is not a contradiction to think, ‘the sun will not rise tomorrow’). We trust such conclusions regarding matters of fact, because we come to have knowledge of causal relations governing such regularities. And this causal knowledge is obtainable only through experience. Leibniz makes a similar distinction between truths of reason and truths of fact: “There are also two kinds of truths, those of reasoning and those of fact. The truths of reasoning are necessary and their opposite is impossible; the truths of fact are contingent, and their opposite is possible. When a truth is necessary, its reason can be found by analysis, resolving it into simpler ideas and simpler truths until we reach the primitives.” (Monadology 33, Philosophical Texts p.272) Kant’s analytic and synthetic judgment distinction is similar to both of these (we examine it below). Quine notes how Morton White claims that “Analytic statements are those whose denials are self-contradictory.” (324) Here White is presenting this as an anti-intensional view that he is critical of. This is not sufficient, White says, because in many cases of a denied formulations that intuitively present a contradiction, there is no syntactically obvious contradiction. For example, “All men are rational animals” would be denied as “It is not the case that all men are rational animals” or as converted to “Some men are not rational animals.” But here we do not have a syntactical contradiction of the form “A and not-A.” Thus, defining analyticity as resulting in a contradiction when denied does not suffice, because we still need a formal account of contradiction (for these cases where it is not syntactically apparent.)]

Kant’s cleavage between analytic and synthetic truths was foreshadowed in Hume’s distinction between relations of ideas and matters of fact, and in Leibniz’s distinction between truths of reason and truths of fact. Leibniz spoke of the truths of reason as true in all possible worlds. Picturesqueness aside, this is to say that the truths of reason are those which could not possibly be false. In the same vein we hear analytic statements defined as statements whose denials are self-contradictory. But this definition has, small explanatory value; for the notion of self-contradictoriness, in the quite broad sense needed for this definition of analyticity, stands in exactly the same need of clarification as does the notion of analyticity itself.2 The two notions are the two sides of a single dubious coin.

(20)

2. See White, op. cit., p. 324.

(20)

[contents]

 

 

 

 

 

 

1.2

[Reformulation Kant’s Notion of Analyticity as Being True by its Meanings and Independently of Fact]

 

[For Kant, an analytic statement is one that “attributes to its subject no more than is already conceptually contained in the subject. (20) Quine notes two problems with this definition: {1} it is limited only to statements in a subject-predicate form (and presumably there are analytic statements not of this form, but Quine does not mention any here) and {2} its notion of containment remains only at a metaphysical level (perhaps because it is not defined formally). Quine sees Kant’s intent and redefines Kant’s analyticity as “a statement is analytic when it is true by virtue of meanings and independently of fact.” (21) We turn now to the notion of meaning used here.]

 

[ditto. Here are some relevant passages from Kant’s Critique of Pure Reason:

On the difference between analytic and synthetic judgments.

In all judgments in which the relation of a subject to the predicate is thought […], this relation is possible in two different ways. Either the predicate B belongs to the subject A as something that is (covertly) contained in this concept A; or B lies entirely outside the concept A, though to be sure it stands in connection with it. In the first case I call the judgment analytic, in the second synthetic. Analytic judgments (affirmative ones) are thus those in which the connection of the predicate is thought through identity, but those in which this connection is thought without identity are to be called synthetic judgments. One could also call the former judgments of clarification and the latter judgments of amplification, since through the predicate the former do not add anything to the concept of the subject, but only break it up by means of analysis into its component concepts, which were already thought in it (though confusedly); while the latter, on the contrary, add to the concept of the subject a predicate that was not thought in it at all, and could not have been extracted from it through any analysis; e.g., if I say: “All bodies are extended,” then this is an analytic judgment. For I do not need to go outside the concept that I combine with the word “body” in order to find that extension is connected with it, but rather I need only to analyze that concept, i.e., become conscious of the manifold that I always think in it, in order to encounter this predicate therein; it is therefore an analytic judgment. On the contrary, if I say: “All bodies are heavy,” then the predicate is something entirely different from that which I think in the mere concept of a body in general. The addition of such a predicate thus yields a synthetic judgment.

Now from this it is clear: 1) that through analytic judgments our cognition is not amplified at all, but rather the concept, which I already | have, is set out, and made intelligible to me; 2) that in synthetic judgments I must have in addition to the concept of the subject something else (X) on which the understanding depends in cognizing a predicate that does not lie in that concept as nevertheless belonging to it.

In the case of empirical judgments or judgments of experience there is no difficulty here. For this X is the complete experience of the object that I think through some concept A, which constitutes only a part of this experience. For although I do not at all include the predicate of weight in the concept of a body in general, the concept nevertheless designates the complete experience through a part of it, to which I can therefore add still other parts of the very same experience as belonging to the former. I can first cognize the concept of body analytically through the marks of extension, of impenetrability, of shape, etc., which are all thought in this concept. But now I amplify my cognition and, in looking back to the experience from which I had extracted this concept of body, I find that weight is also always connected with the previous marks. Experience is therefore that X that lies outside the concept A and on which the possibility of the synthesis of the predicate of weight B with the concept A is grounded.

(Kant, Critique of Pure Reason, 130-131)

]

 

Kant conceived of an analytic statement as one that attributes to its subject no more than is already conceptually contained in the subject. | This formulation has two shortcomings : it limits itself to statements of subject-predicate form, and it appeals to a notion of containment which is left at a metaphorical level. But Kant’s intent, evident more from the use he makes of the notion of analyticity than from his definition of it, can be restated thus : a statement is analytic when it is true by virtue of meanings and independently of fact. Pursuing this line, let us examine the concept of meaning which is presupposed.

(20-21)

[contents]

 

 

 

 

 

 

1.3

[Meaning as Not Referential Naming]

 

[Meaning cannot be mere reference, because there are cases where two different names name the same thing, but each name has a different meaning, as for instance Frege’s ‘Evening Star = Morning Star’. As the two names are not identical in meaning, this statement is not analytic. (In fact, the meaning of ‘the evening star’ is almost the opposite of the meaning of ‘morning star’.) Also the identity made between the two is a statement of fact that is demonstrated through astronomical observation. (Thus it does not fulfill either of the Kantian requirements that an analytic statement be “true by virtue of meanings and independently of fact.”).]

 

[ditto]

We must observe to begin with that meaning is not to be identified with naming, or reference. Consider Frege’s example of ‘Evening Star’ and ‘Morning Star’. Understood not merely as a recurrent evening apparition but as a body, the Evening Star is the planet Venus, and the Morning Star is the same. The two singular terms name the same thing. But the meanings must be treated as distinct, since the· identity ‘Evening Star = Morning Star’ is a statement of fact established by astronomical observation. If ‘Evening Star’ and ‘Morning Star’ were alike in meaning, the identity ‘Evening Star = Morning Star’ would be analytic.

(21)

[contents]

 

 

 

 

 

 

1.4

[Russell’s “Author of Waverley” as Another Example of an Identifying Naming Statement That Is Not Analytical]

 

[Another example of a case where equated names do not render an analytic statement is Russell’s “Scott is the author of Waverley.”]

 

[ditto. It seems Sir Walter Scott wrote Waverley anonymously, and published certain subsequent writings under “the author of Waverley.” (see here and here) And “His identity as the author of the novels was widely rumoured, and in 1815 Scott was given the honour of dining with George, Prince Regent, who wanted to meet ‘the author of Waverley’’.” (source for this quote) Here are some relevant passages from Russell’s “On Denoting”:

If we say “Scott is the author of Waverley,” we assert an identity of denotation with a difference of meaning.”

(483)

If a is identical with b, whatever is true of the one is true of the other, and either may be substituted for the other in any proposition without altering the truth or falsehood of that proposition. Now George IV. wished to know whether Scott was the author of Waverley; and in fact Scott was the author of Waverley. Hence we may substitute Scott for the author of “Waverley,” and thereby prove that George IV. wished to know whether Scott was Scott. Yet an interest in the law of identity can hardly be attributed to the first gentleman of Europe.

(485)

Quine’s point might seem to be the following. George IV knew about the author of Waverley, and he may have even known Sir Walter Scott. But neither name is contained in the other.]

Again there is Russell’s example of ‘Scott’ and ‘the author of Waverley’. Analysis of the meanings of words was by no means sufficient to reveal to George IV that the person named by these two singular terms was one and the same.

(21)

[contents]

 

 

 

 

 

 

1.5

[Abstract Terms as Also Having This Problem (“9” and “The Number of Planets”)]

 

[Even with abstract terms, like number values,  we still have this problem, as “9” and “the number of planets” names one and the same abstract entity (the number value of nine), but the equation of the two is not analytic; for, observation was needed to make that equation, and a reflection on their meanings is insufficient too.]

 

[ditto]

The distinction between meaning and naming is no less important at the level of abstract terms. The terms ‘9’ and ‘the number of planets’ name one and the same abstract entity but presumably must be regarded as unlike in meaning; for astronomical observation was needed, and not mere reflection on meanings, to determine the sameness of the entity in question.

(21)

[contents]

 

 

 

 

 

 

1.6

[Meaning and Extension for General Terms (“Creature with a Heart” and “Creature with a Kidney”]

 

[A general term or predicate does not name an entity, but it is true of an entity or entities, or of none. The extension of a general term is that class of all entities that a general term is true of. With singular terms, we distinguished its meaning from its extension (Evening Star and Morning Star have the same extension, the planet Venus, but different meanings); similarly, we must do the same for general terms. So for example, the general terms “creature with a heart” and “creature with a kidney” may have an identical extension (supposing all creatures with the one organ also in fact have the other), but they are not alike in meaning.]

 

[ditto]

Thus far we have been considering singular terms. With general terms, or predicates, the situation is somewhat different but parallel. Whereas a singular term purports to name an entity, abstract or concrete, a general term does not; but a general term is true of an entity, or of each of many, or of none. The class of all entities of which a general term is true is called the extension of the term. Now paralleling the contrast between the meaning of a singular term and the entity named, we must distinguish equally between the meaning of a general term and its extension. The general terms ‘creature with a heart’ and | ‘creature with a kidney’, e.g., are perhaps alike in extension but unlike in meaning.

(21-22)

[contents]

 

 

 

 

 

 

1.7

[Intention (Meaning)/Connotation Vs. Extension/Denotation]

 

[We sometimes contrast intension (or meaning) and connotation with extension or denotation.]

 

[ditto]

Confusion of meaning with extension, in the case of general terms, is less common than confusion of meaning with naming in the case of singular terms. It is indeed a commonplace in philosophy to oppose intension (or meaning) to extension, or, in a variant vocabulary, connotation to denotation.

(22)

[contents]

 

 

 

 

 

 

1.8

[Aristotle’s Essence as Being Similar to Meaning, but Not Identical]

 

[Aristotle’s notion of essence was a forerunner for what we now call intension (meaning). Aristotle distinguishes the essential from the accidental, so for humans, it is essential to be rational, but it is accidental to have two legs. Quine notes a problem. Consider a human person. They will be both rational and two-legged. Quine observes however that we may classify this person either as a human or a biped. Insofar as they are a human, their rationality is essential and their bipedalism is not. But insofar as they are a biped, their two-leggedness is essential and their rationality is not. (Here Quine claims that we are dealing with meanings rather than essences. We might say under a doctrine of essences that for some particular individual person, their rationality is essential and their bipedalism is not. However, under a doctrine of meanings, for this individual’s predicates of being rational and bipedal, it cannot be said that one of them is essential and the other is not. For, by the same reasoning that we would use to designate one over the other, we may equally use it to designate the other over the first. (We might say, “here is a human,” and take their rationality as essential; or, for the same person, we might say, “here is a biped” and take their two-leggedness as essential. This is because in that case we are concerned with meanings (of “human” and of “biped”) rather than with the entity itself’s proper essence).) “Things had essences, for Aristotle, but only linguistic forms have meanings. Meaning is what essence becomes when it is divorced from the object of reference and wedded to the word.” (22)]

 

[ditto]

The Aristotelian notion of essence was the forerunner, no doubt, of the modern notion of intension or meaning. For Aristotle it was essential in men to be rational, accidental to be two-legged. But there is an important difference between this attitude and the doctrine of meaning. From the latter point of view it may indeed be conceded (if only for the sake of argument) that rationality is involved in the meaning of the word ‘man’ while two-leggedness is not; but two-leggedness may at the same time be viewed as involved in the meaning of ‘biped’ while rationality is not. Thus from the point of view of the doctrine of meaning it makes no sense to say of the actual individual, who is at once a man and a biped, that his rationality is essential and his two-leggedness accidental or vice versa. Things had essences, for Aristotle, but only linguistic forms have meanings. Meaning is what essence becomes when it is divorced from the object of reference and wedded to the word.

(22)

[contents]

 

 

 

 

 

 

 

1.9

[Difficulty in Defining What Kind of Entities Meanings Are]

 

[In a theory of meaning, we would need to explain what kind of objects meanings are. They seem to be ideas. For semanticists, they are mental ideas. For others, they are Platonic ideas. But these characterizations are not sufficient because such entities are too elusive to erect “a fruitful science about them.” (22) Some things are often not clear about such entities: {1} whether we have two or one; and {2} when linguistic forms are synonymous or not. ]

 

[ditto]

For the theory of meaning the most conspicuous question is as to the nature of its objects: what sort of things are meanings? They are evidently intended to be ideas, somehow – mental ideas for some semanticists, Platonic ideas for others. Objects of either sort are so elusive, not to say debatable, that there seems little hope of erecting a fruitful science about them. It is not even clear, granted meanings, when we have two and when we have one; it is not clear when linguistic forms should be regarded as synonymous, or alike in meaning, and when they should not. If a standard of synonymy should be arrived at, we may reasonably expect that the appeal to meanings as entities will not have played a very useful part in the enterprise.

(22)

[contents]

 

 

 

 

 

 

1.10

[Defining Meaning as Superfluous]

 

[But once we distinguish a theory of meaning from a theory of reference, we can then think of meanings just in terms of synonymy of linguistic forms and the analyticity of statements.]

 

[ditto]

A felt need for meant entities may derive from an earlier failure to appreciate that meaning and reference are distinct. Once the theory of meaning is sharply separated from the theory of reference, it is a short step to recognizing as the business of the theory of meaning | simply the synonymy of linguistic forms and the analyticity of statements; meanings themselves, as obscure intermediary entities, may well be abandoned.

(22-23)

[contents]

 

 

 

 

 

 

1.11

[Abandoning Meaning for Defining Analyticity]

 

[We began wondering how to define analyticity. (We saw in the Kantian conception that it can be understood as being true by meanings and independently of fact. See 1.2. We distinguished meaning from extension. Then we found that meanings are hard to define and unnecessary when we have extension.) We now no longer consider a “special realm of entities called meanings.” (23) That means we must find other ways to understand analyticity.]

 

[ditto]

The description of analyticity as truth by virtue of meanings started us off in pursuit of a concept of meaning. But now we have abandoned the thought of any special realm of entities called meanings. So the problem of analyticity confronts us anew.

(23)

[contents]

 

 

 

 

 

 

1.12

[Logically True Analytic Statements]

 

[Statements that are often considered analytic in philosophy are generally of two types. {1} Ones that are logically true, for instance (1) No unmarried man is married. (This is true no matter what the interpretations are of the terms. It is formally true.)]

 

[ditto]

Statements which are analytic by general philosophical acclaim are not, indeed, far to seek. They fall into two classes. Those of the first class, which may be called logically true, are typified by:

(1) No unmarried man is married.

The relevant feature of this example is that it is not merely true as it stands, but remains true under any and all reinterpretations of ‘man’ and ‘married’. If we suppose a prior inventory of logical particles, comprising ‘no’, ‘un-’, ‘not’, ‘if’, ‘then’, ‘and’, etc., then in general a logical truth is a statement which is true and remains true under all reinterpretations of its components other than the logical particles.

(23)

[contents]

 

 

 

 

 

1.13

[Statements Made Logically True by Substitutions]

 

[{2} The other kind of analytic statements are ones that can be rendered into a logically true format by substituting synonyms. For example, (2) “No bachelor is married” can be rendered “No unmarried man is married” but substituting the synonyms “bachelor” and “unmarried man”. Yet, we do not have a proper (formal?) characterization of these kinds of analytic statements, especially since we do not have a (formal?) definition of synonymy. Thus we do not have an adequate (formal?) characterization of analyticity.]

 

[ditto]

But there is also a second class of analytic statements, typified by:

(2) No bachelor is married.

The characteristic of such a statement is that it can be turned into a logical truth by putting synonyms for synonyms; thus (2) can be turned into (1) by putting ‘unmarried man’ for its synonym ‘bachelor’. We still lack a proper characterization of this second class of analytic statements, and therewith of analyticity generally, inasmuch as we have had in the above description to lean on a notion of “synonymy” which is no less in need of clarification than analyticity itself.

(23)

[contents]

 

 

 

 

 

1.14

[Carnap’s Definition of Logical Truths (Analyticity)]

 

[Carnap defines analyticity in the following way. We begin by assigning all the truth values to every atomic statement in a language. Each complete combination of assignments for all the atomic sentences is what he calls a “state description.” We can then compositionally build up the complex statements of the language using logical means, with their truth values being computable based on logical laws. A statement is analytic when it is true under every state description. Since a state description is like a possible world (it is one combination of facts), this can be seen as following Leibniz’ notion of being true in all possible worlds. (Quine then explains a problem with this conception: if the language has extralogical synonym-pairs, such as ‘bachelor’ and ‘unmarried man’, then statements like “All bachelors are married” will turn out to be synthetic rather than analytic. Thus) “The criterion in terms of state-descriptions is a reconstruction at best of logical truth.” (24)]

 

[ditto. (Note: I did not understand Quine’s objection. According to Quine, a statement is analytically true (L-true) in a system if it is true in all possible state-descriptions. It is L-false if its negation is L-true, meaning that the statement does not hold in any state description.  The sentence is L-determinate if it is either L-true or L-false. And it is L-indeterminate or factual (synthetic) if it is not L-determinate, meaning that there is at least one state-description in which it holds and at least one in which it does not hold. (See Carnap block quotes below.) Now, suppose two cases. {1} In our system, we have a way to derive formulas based on meaning, so in worlds where ‘John is a bachelor’ is true, then in that same world, ‘John is married’ is false (and vice versa). That would presumably make ‘All bachelors are married’ false in every state description. That would make ‘All bachelors are married’ L-false, and thus L-determinate. As such, it would not be synthetic. Yet, Quine claims it makes it synthetic. I did not understand why yet. (I can only see it working if it is both true and false that John is a bachelor and both true and false that John is married.) However, it also would not be analytic, because it is not true in all worlds. {2} In the second case, Quine says we do not have such sentences with mutually dependent truth values. But does he mean we cannot have both “bachelor” and “married” in the same world? What kind of a language would we have without terms that imply opposite meanings? Would it be just a formal system of symbols? Or is he saying that we do have ‘John is a bachelor’ and ‘John is married’ , but the truth of the one does not entail the falsity of the other? Still, that would not make “All bachelors are married” analytic, because there would still be worlds where we assign ‘John is a bachelor’ as true and ‘John is married’ as false. Thus still “All bachelors are married” would not hold in every possible world (state description). So I am not sure what Quine’s objection is here yet.)  Below are some relevant passages from Carnap’s text.

In order to speak about expressions in a general way, we often use ‘Ai’, ‘Aj’, etc.,  for expressions of any kind and ‘Si’, ‘Sj’, etc., for sentences ...

(Carnap 4. Note: here and below, the bold “A” should instead be Mathematical Bold Fraktur Capital A; and the Bold “S” should be Mathematical Bold Fraktur Capital S)

The task of making more exact a vague or not quite exact concept used in everyday life or in an earlier stage of scientific or logical development, | or rather of replacing it by a newly constructed, more exact concept, belongs among the most important tasks of logical analysis and logical construction. We call this the task of explicating, or of giving an explication for, the earlier concept; this earlier concept, or sometimes the term used for it, is called the explicandum; and the new concept, or its term, is called an explicatum of the old one.  Thus, for instance, Frege and, later, Russell took as explicandum the term ‘two’ in the not quite exact meaning in which it is used in everyday life and in applied mathematics; they proposed as an explicatum for it an exactly defined concept, namely, the class of pair-classes [...]; other logicians have proposed other explicata for the same explicandum. Many concepts now defined in semantics are meant as explicata for concepts earlier used in everyday language or in logic. For instance, the semantical concept of truth has as its explicandum the concept of truth as used in everyday language (if applied to declarative sentences) and in all of traditional and modern logic. [...] Generally speaking, it is not required that an explicatum have, as nearly as possible, the same meaning as the explicandum; it should, however, correspond to the explicandum in such a way that it can be used instead of the latter.

The L-terms (‘L-true’, etc.) which we shall now introduce are likewise intended as explicata for customary, but not quite exact, concepts. ‘L-true’ is meant as an explicatum for what Leibniz called necessary truth and Kant analytic truth. We shall indicate here briefly how this and the other L-terms can be defined.

(Carnap 7-8)

A class of sentences in S1 which contains for every atomic sentence either this sentence or its negation, but not both, and no other sentences, is called a state-description in S1 , because it obviously gives a complete description of a possible state of the universe of individuals with respect to all properties and relations expressed by predicates of the system. Thus the state-descriptions represent Leibniz' possible worlds or Wittgenstein's possible states of affairs.

It is easily possible to lay down semantical rules which determine for every sentence in S1 whether or not it holds in a given state-description. That a sentence holds in a state-description means, in nontechnical terms, that it would be true if the state-description (that is, all sentences belonging to it) were true. A few examples will suffice to show the nature of these rules: (1) an atomic sentence holds in a given state-description if and only if it belongs to it; (2) ~Si holds in a given state-description if and only if Si does not hold in it; (3) Si Sj, holds in a state-description if and only if either Si holds in it or Sj or both; ...

(Carnap 9)

Our concept of L-truth is, as mentioned above, intended as an explicatum for the familiar but vague concept of logical or necessary or analytic truth as explicandum. This explicandum has sometimes been characterized as truth based on purely logical reasons, on meaning alone, independent of the contingency of facts. Now the meaning of a sentence, its interpretation, is determined by the semantical rules (the rules of designation and the rules of ranges in the method explained above). Therefore, it seems well in accord with the traditional concept which we take as explicandum, if we require of any explicatum that it fulfil the following condition:

2-1. Convention. A sentence Si is L-true in a semantical system S if and only if Si is true in S in such a way that its truth can be established on the basis of the semantical rules of the system S alone, without any reference to (extra-linguistic) facts.

This is not yet a definition of L-truth. It is an informal formulation of a condition which any proposed definition of L-truth must fulfil in order to be adequate as an explication for our explicandum. Thus this convention has merely an explanatory and heuristic function.

How shall we define L-truth so as to fulfil the requirement 2-1? A way is suggested by Leibniz' conception that a necessary truth must hold in all possible worlds. Since our state-descriptions represent the possible worlds, this means that a sentence is logically true if it holds in all state-descriptions. This leads to the following definition:

2-2. Definition. A sentence Si is L-true (in S1) =Df  Si holds in every state-description (in S1).

(Carnap 10)

2-3. Definitions

a. Si  is L-false in (S1) =Df ~Si is L-true.

[...]

d. Si is L-determinate (in S1) =Df Si  is either L-true or L-false.

[...]

2-4. Si is L-false if and only if Si does not hold in any state-description.

(Carnap 11)

We have seen that our concept of L-truth fulfils our earlier convention 2-1. Therefore, according to the definition 2-3d, a sentence is L-determinate if and only if the semantical rules, independently of facts, suffice for establishing its truth-value, that is, either its truth or its falsity. This suggests the following definition, 2-7, as an explication for what Kant called synthetic judgments. The subsequent result, 2-8, which follows from the definition, shows that the concept defined is indeed adequate as an explicatum.

2-7. Definition. Si is L-indeterminate or factual (in S1) =Df   Si  is not L-determinate.

2-8. A sentence is factual if and only if there is at least one state-description in which it holds and at least one in which it does not hold.

(Carnap 12)

]

In recent years Carnap has tended to explain analyticity by appeal to what he calls state-descriptions.3 A state-description is any exhaustive assignment of truth values to the atomic, or noncompound, statements of the language. All other statements of the language are, Carnap assumes, built up of their component clauses by means of the familiar logical devices, in such a way that the truth value of any complex statement is fixed for each state-description by specifiable logical laws. A statement is then explained as analytic when it comes out true under every state-description. This account is an adaptation | of Leibniz’s “true in all possible worlds.” But note that this version of analyticity serves its purpose only if the atomic statements of the language are, unlike ‘John is a bachelor’ and ‘John is married’, mutually independent. Otherwise there would be a state-description which assigned truth to ‘John is a bachelor’ and falsity to ‘John is married’, and consequently ‘All bachelors are married’ would turn out synthetic rather than analytic under the proposed criterion. Thus the criterion of analyticity in terms of state-descriptions serves only for languages devoid of extralogical synonym-pairs, such as ‘bachelor’ and ‘unmarried man’: synonym-pairs of the type which give rise to the “second class” of analytic statements. The criterion in terms of state-descriptions is a reconstruction at best of logical truth.

(23-24)

3. R. Carnap, Meaning and Necessity (Chicago, 1947), pp. 9ff.; Logical Foundations of Probability (Chicago, 1950), pp. 70ff.

(23)

[contents]

 

 

 

 

 

1.15

[Turning Instead to Analyticity From Synonymy]

 

[Yet, Carnap’s main concern was clarifying probability and induction, not analyticity, which is our concern, “and here the major difficulty lies not in the first class of analytic statements, the logical truths, but rather in the second class, which depends on the notion of synonymy.” (23)]

 

[ditto]

I do not mean to suggest that Carnap is under any illusions on this point. His simplified model language with its state-descriptions is aimed primarily not at the general problem of analyticity but at another purpose, the clarification of probability and induction. Our problem, however, is analyticity; and here the major difficulty lies not in the first class of analytic statements, the logical truths, but rather in the second class, which depends on the notion of synonymy.

(24)

[contents]

 

 

 

 

 

 

Bibliography:

Quine, W. V. “Two Dogmas of Empiricism.” The Philosophical Review 60, no. 1 (1951): 20–43.

 

 

Carnap, Rudolf. Meaning and Necessity: A Study in Semantics and Modal Logic. Chicago: University of Chicago, 1947.

 

Kant, Immanuel. Critique of Pure Reason. Edited and translated by Paul Guyer and Allen W. Wood. Cambridge: Cambridge University, 1998.

 

Leibniz, Gottfried. “Monadology.” In Philosophical Texts, edited and translated by Richard Francks and Roger Woolhouse, 267–81. Oxford: Oxford University, 1998.

 

Russell, Bertrand. “On Denoting.” Mind 14, no. 56 (1905): 479–93.

 

White, Morton. “The Analytic and the Synthetic: An Untenable Dualism.” In John Dewey: Philosopher of Science and Freedom. a Symposium, edited by Sidney Hook, 316–30. New York: Dial, 1950.

 

 

.

 

 

.

23 Jul 2018

Priest (11a.7) An Introduction to Non-Classical Logic, ‘Future Contingents Revisited,’ summary

 

by Corry Shores

 

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[The following is summary of Priest’s text, which is already written with maximum efficiency. Bracketed commentary and boldface are my own, unless otherwise noted. I do not have specialized training in this field, so please trust the original text over my summarization. I apologize for my typos and other unfortunate mistakes, because I have not finished proofreading, and I also have not finished learning all the basics of these logics.]

 

 

 

 

Summary of

 

Graham Priest

 

An Introduction to Non-Classical Logic: From If to Is

 

Part I:

Propositional Logic

 

11a

Appendix: Many-valued Modal Logics

 

11a.7

Future Contingents Revisited

 

 

 

 

Brief summary:

(11a.7.1) We may use many-valued modal logics for contending with the problem of future contingents. Aristotle’s analysis of them lends to the many-valued solutions. We begin with the intuition that there are contingent future events for which there are presently no facts that could make them true or false, (as for example, “The first pope in the twenty-second century will be Chinese” (132)). We then suppose that right now a statement about a future contingent is true (or false). That would mean that it cannot be otherwise, and thus fatalism would hold if future contingents are presently either true or false. But that goes against our original intuition that nothing in the present makes such statements true or false, so Aristotle concludes that statements about future contingents cannot have either the value true or false. (11a.7.2) Priest next quotes the important Aristotle passage for this discussion of future contingents, from De Int. 18b10–16.

. . . if a thing is white now, it was true before to say that it would be white, so that of anything that has taken place, it was always true to say ‘it is’ or ‘it will be’. But if it was always true to say that a thing is or will be, it is not possible that it should not be or not come to be, and when a thing cannot not come to be, it is impossible that it should not come to be, and when it is impossible that it should not come to be, it must come to be. All then, that is about to be must of necessity take place. It results from this that nothing is uncertain or fortuitous, for if it were fortuitous it would not be necessary. 

(251-252, quoting De Int. 18b10–16. Translation from Vol. 1 of Ross (1928).)

(11a.7.3) This argument may be read in the following way. “Let q be any statement about a future contingent event. Let Tq be the statement that it is (or was) true that q. Then □(Tqq). Hence Tq ⊃ □q. And since □q is not true, neither is Tq. A similar argument can be run for ¬q. So neither Tq nor T¬q holds. Read in this way, the reasoning contains a modal fallacy (passing from □(A B) to (A ⊃ □B))” (252). (11a.7.4) The above reading is incorrect, because Aristotle holds that the past and present are unchangeable and thus necessary. So the inference from □(Tqq) should be □Tq ⊃ □q, which is valid. (11a.7.5) The above argument can be formulated without the conditional or the Tq formula. We have the statement about the future, q. “If q were true, this would be a present fact, and so fixed; that is, it would be necessarily true, that is: q ⊨ □q. Similarly, if it were false, it would be necessarily false: ¬q ⊨ □¬q. Since neither □q nor □¬q holds, neither q nor ¬q holds” (252). (11a.7.6) Aristotle does not allow exceptions to the Law of Non-Contradiction. So the sort of many-valued modal logic we use in application to his Future  Contingents argument should validate it. Thus we should not use KFDE or KLP but rather KK3, in which there is the option for formulas to be neither true nor false, but not the option for contradictions. (11a.7.7) In our many-valued modal logic, we indicate futurity with the R accessibility relation:“Think of the accessibility statement wRw′ as meaning that w′ may be obtained from w by some number (possibly zero) of further things happening” (252). Given the nature of time, R is reflexive and transitive but not symmetrical. To capture Aristotle’s assumption that “once something is true/false, it stays so,” we will use a modified heredity constraint called the Persistence Constraint: “for every propositional parameter, p, and world, w:

If pρw1 and wRw′, pρw1

If pρ w0 and wRw′, pρ w0

(11a.7.8) The persistence constraint does not hold for modalized formulas. (11a.7.9) Our many-valued K3ρτ logic, augmented by the Persistence Constraint, is called A (for Aristotle). “In this logic p ⊨ □p and ¬p ⊨ □¬p. Aristotle’s argument therefore works. But, of course, in A, p ¬p may fail to be true.” (11a.7.10) For our Aristotle logic A, neither □p not □¬p holds. However, Aristotle thinks that eventually p or ¬p will have to hold, thus he thinks □(p ¬p). Yet, this does not hold in logic A. (11a.7.11) To allow □(p ¬p) to hold in logic A, we can take a temporal perspective of the end of time when everything has been decided. “Call a world complete if every propositional parameter is either true or false. A natural way of giving the truth conditions for □ is as follows: 

Aρw1 iff for all complete w′ such that wRw′, Aρw′1

Aρw0 iff for some complete w′ such that wRw′, Aρw′ 0

The truth/falsity conditions for ◊ are the same with ‘some’ and ‘all’ interchanged. □A may naturally be seen as expressing the idea that A is inevitable. [...] for any complete world, w, Persistence holds for all formulas. It follows that at such a world, A is true iff □A is, and that all formulas are either true or false” (254). (11a.7.12) These above revised truth/falsity conditions for necessity allow us to capture the important assumptions and valid inferences in Aristotle’s argumentation regarding future contingency, namely: “p ⊨ □p, ¬p ⊨ □¬p (so Aristotle’s argument still works), ⊨ □(p ∨ ¬p), but not ⊨ □p ∨ □¬p” (254).

 

 

 

 

 

 

Contents

 

11a.7.1

[Many-Valued Modal Logics and Future Contingents. Aristotle’s Analysis.]

 

11a.7.2

[Aristotle’s Formulation of the Fatalism from Affirming the Present Truth of Future Contingents]

 

11a.7.3

[One Possible Formal Reading of Aristotle’s Argument]

 

11a.7.4

[A More Accurate Reading]

 

11a.7.5

[A Simplification of the Argument]

 

11a.7.6

[Using KK3]

 

11a.7.7

[The R Relation and the Persistence Constraint]

 

11a.7.8

[The Non-Holding of the Persistence Constraint for Modalized Formulas]

 

11a.7.9

[Logic A and the Success of Aristotle’s Argument]

 

11a.7.10

[A Missing Notion in Logic A]

 

11a.7.11

[Using Complete Worlds to Remedy the Problem with Logic A]

 

11a.7.12

[The Success of Modified Logic A]

 

 

 

 

 

Summary

 

11a.7.1

[Many-Valued Modal Logics and Future Contingents. Aristotle’s Analysis.]

 

[We may use many-valued modal logics for contending with the problem of future contingents. Aristotle’s analysis of them lends to the many-valued solutions. We begin with the intuition that there are contingent future events for which there are presently no facts that could make them true or false, (as for example, “The first pope in the twenty-second century will be Chinese” (132)). We then suppose that right now a statement about a future contingent is true (or false). That would mean that it cannot be otherwise, and thus fatalism would hold if future contingents are presently either true or false. But that goes against our original intuition that nothing in the present makes such statements true or false, so Aristotle concludes that statements about future contingents cannot have either the value true or false.]

 

[Recall from section 7.9 our discussion of future contingents, which are statements about the future that can be uttered now but for which there presently are no facts that make them true or false, as for example: “The first pope in the twenty-second century will be Chinese” (p.132, section 7.9.1). Priest notes now that many-valued modal logics can further our analysis of this philosophical problem of future contingents. Now suppose that we have a statement we utter now about a future contingent. If it is true, then in fact nothing else can happen, and if it is false, it certainly cannot happen. Aristotle argues that if statements about future contingents that are uttered now must take either the value true or the value false, then fatalism holds. For, every future event is already determined. But then, this goes against our original intuition that they really are contingent events. And so Aristotle says that statements about future contingents cannot be true or false.]

Many-valued modal logics engage with a number of philosophical controversies. Let me illustrate with respect to Aristotle’s argument concerning future contingents, which we met in 7.9. In De Interpretatione, ch. 9, Aristotle argued famously that if contingent statements about the future were now either true or false, fatalism would follow. He therefore denied that contingent statements about the future are true or false.

(252)

[contents]

 

 

 

 

 

 

11a.7.2

[Aristotle’s Formulation of the Fatalism from Affirming the Present Truth of Future Contingents]

 

[Priest next quotes the important Aristotle passage for this discussion of future contingents, from De Int. 18b10–16.]

 

[Priest next quotes the relevant passages in Aristotle’s De Int. 18b10–16. Here Aristotle explains how one might come to the fatalistic conclusion we mention above in section 11a.7.1. Someone might know how something is white right now in the present. That means, at any time in the past, the statement, “the thing will be white,” would be true. This holds for anything that happens. If it happens, then it is true to say that it is so, and it would be true in the past to say that it will be so. But someone might then infer that every future event, before it happens, were it stated, would be true. Here Aristotle introduces some notions of possibility and impossibility. So given any future event that can be stated now in advance, supposing the statement to be true, then it is impossible for that event not to happen later in the future. Thus, “All then, that is about to be must of necessity take place”. Hence nothing happens by chance.]

The argument that the law of excluded middle entails fatalism is worth quoting in detail:2

. . . if a thing is white now, it was true before to say that it would be white, so that of anything that has taken place, it was always true to say ‘it is’ or ‘it | will be’. But if it was always true to say that a thing is or will be, it is not possible that it should not be or not come to be, and when a thing cannot not come to be, it is impossible that it should not come to be, and when it is impossible that it should not come to be, it must come to be. All then, that is about to be must of necessity take place. It results from this that nothing is uncertain or fortuitous, for if it were fortuitous it would not be necessary.

(251-252)

2. De Int. 18b10–16. Translation from Vol. 1 of Ross (1928).

(251-252)

[contents]

 

 

 

 

 

 

11a.7.3

[One Possible Formal Reading of Aristotle’s Argument]

 

[This argument may be read in the following way. “Let q be any statement about a future contingent event. Let Tq be the statement that it is (or was) true that q. Then □(Tqq). Hence Tq ⊃ □q. And since □q is not true, neither is Tq. A similar argument can be run for ¬q. So neither Tq nor T¬q holds. Read in this way, the reasoning contains a modal fallacy (passing from □(A B) to (A ⊃ □B))” (252). ]

 

[Priest next will give a modal formulation of the above argument from section 11a.7.2. (Here he seems to be including certain sorts of tense senses, but I cannot tell if he is using a tense logic (see section 3.6a and section 3.6b .)) Let us look at the first sentence: “if a thing is white now, it was true before to say that it would be white, so that of anything that has taken place, it was always true to say ‘it is’ or ‘it will be’.” (We begin with the following structure. Something is white now. That means any statement made in the past about it being white now would be true.) So even though we are speaking about the present situation where the thing is white, we are transporting our temporal perspective into the past, and we are saying that in the past, it was true to say what is now true in the present. Now, staying in the past perspective, we have “it will be white”. Here Priest says we will call such statements about a contingent future, q. The next part read, “But if it was always true to say that a thing is or will be, it is not possible that it should not be or not come to be, and when a thing cannot not come to be, it is impossible that it should not come to be, and when it is impossible that it should not come to be, it must come to be.” Here we begin with, “if it was always true to say that a thing is or will be.” Recall that our statement of the future contingent situation is called q. Priest will have us call Tq the statement that it is now true that q (or that it was true). So in our example, our Tq would seem to be something like “it is now true that it will be white” or “it was true that it will be white.” And let us look at the second part of that sentence which was “if it was always true to say that a thing is or will be, it is not possible that it should not be or not come to be, and when a thing cannot not come to be, it is impossible that it should not come to be...”. The next formulation Priest mentions is: □(Tqq). But I am not sure if that comes from the cited sentences or how otherwise we obtain it. Maybe we should look at the phrase, “it is not possible that it should not be” in the fuller clause, “if it was always true to say that a thing is or will be, it is not possible that it should not be or not come to be.” As far as I would guess, “not possible not” would be something like ¬◊¬ (see for example Nolt’s Logics, section 11.1), and thus we would have Tq ⊃ ¬◊¬q  or Tq ⊃ □q. But that is the next formulation we are to draw from □(Tqq). So I am still trying to figure out where that comes from. Maybe for it, we think of the Tq as being in the past and the q as now, thus the □(Tqq) would mean maybe something like what is said in “. . . if a thing is white now, it was true before to say that it would be white, so that of anything that has taken place, it was always true to say ‘it is’ or ‘it will be’.” I am sorry that I cannot find it exactly with the language for the necessity operator. At any rate, we do get something straightforwardly like,  Tq ⊃ □q when Aristotle writes, “All then, that is about to be must of necessity take place.” Priest then notes the rest of this argumentation, which seems to maybe come after our quotation, namely, that since as we assumed about future contingents that it cannot be □q, (for, were it necessary than it would no longer be contingent), that means it cannot be that Tq (by modus tollens), (so it cannot be that it our statement about the future is true now or in the past.) Priest says we can make a similar argument for ¬q. Thus “neither Tq nor T¬q holds.” Next Priest notes that when we construe the argument in this manner, we find that one of the inferences is invalid (that “the reasoning contains a modal fallacy”), namely, “passing from □(A B) to (A ⊃ □B))”. As we saw in section 7.9, many commentators read the problem this way. (Let me just try to understand the situation. I will attempt to make the tableau for this inference, but I know it is likely mistaken:

 

□(Tq ⊃ q) Tq ⊃ □q

1.

.

2.

.

3.

.

4.

.

5.

.

6.

.

7.

.

8.

.

9.

.

 

.

□(Tq ⊃ q),0

¬(Tq ⊃ □q),0

Tq,0

¬□q,0

¬q,0

0r1

¬q,1

Tq ⊃ q,1

↙     ↘

¬Tq,1        q,1

               × 

P

.

P

.

2¬⊃

.

2¬⊃

.

4¬□

.

5◊r

.

5◊r

.

1,6r

.

8⊃

(9b×7)

open

invalid

(This is not in the text and it is likely mistaken.)

 

However, I was able to get it to close by structuring it like the “distribution axiom” which I came across here.

 

□(Tq ⊃ q) Tq ⊃ □q

1.

.

2.

.

3.

.

4.

.

5.

.

6.

.

7.

.

8.

.

9.

.

10.

.

 

.

□(Tq ⊃ q),0

¬(Tq ⊃ □q),0

Tq,0

¬□q,0

◊¬q,0

0r1

¬q,1

Tq ⊃ q,1

↙     ↘

¬Tq,1        q,1

↓            ×

Tq,1           

×            

        

 

P

.

P

.

2¬⊃

.

2¬⊃

.

4¬□

.

5◊r

.

5◊r

.

1,6r

.

8⊃

(9b×7)

3,6r

(10×9)

closed

valid

(This is not in the text and it is likely mistaken.)

]

One way to read the passage is as follows. Let q be any statement about a future contingent event. Let Tq be the statement that it is (or was) true that q. Then □(Tqq). Hence Tq ⊃ □q. And since □q is not true, neither is Tq. A similar argument can be run for ¬q. So neither Tq nor T¬q holds. Read in this way, the reasoning contains a modal fallacy (passing from □(A B) to (A ⊃ □B)). Many commentators have read the passage thus (see 7.9).

(252)

 

[contents]

 

 

 

 

 

 

11a.7.4

[A More Accurate Reading]

 

[The above reading is incorrect, because Aristotle holds that the past and present are unchangeable and thus necessary. So the inference from □(Tqq) should be □Tq ⊃ □q, which is valid.]

 

[(The part that we might find odd in the above formal reading of Aristotle’s argument in section 11a.7.3 is where it says: Tq ⊃ □q. It seems to leave out the fact the assumption that something true in the past or present cannot be changed, and thus it should really read □Tq ⊃ □q, which, as we saw in the second tableau above in section 11a.7.3, was validly inferable from □(Tqq). Priest may be making a different point, so please check the quotation.)]

But this may not do Aristotle justice. It is clear that he thinks that the past and present are fixed (unchangeable, now inevitable). So if s is a statement about the past or present, s ⊃ □s. Hence, Tq ⊃ □Tq, and since □(Tqq), so that □Tq ⊃ □q, it follows that Tq ⊃ □q. There is no fallacy here.

(252)

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11a.7.5

[A Simplification of the Argument]

 

[The above argument can be formulated without the conditional or the Tq formula. We have the statement about the future, q. “If q were true, this would be a present fact, and so fixed; that is, it would be necessarily true, that is: q ⊨ □q. Similarly, if it were false, it would be necessarily false: ¬q ⊨ □¬q. Since neither □q nor □¬q holds, neither q nor ¬q holds” (252).]

 

[Priest next explains how we can simplify the argument by removing the conditional and Tq. (I will not summarize it well, but it might be the following. We have q, which is already a statement about the future. We suppose it is true, making it a present fact. As such, it is fixed and thus necessarily true. So, q ⊨ □q. And if it were false, (or if its negation held, as it seems from the formulation), it would likewise be fixed and thus necessarily false (or its negation necessarily holding). But, given that q is a future contingent, by definition neither □q nor □¬q, and thus neither q nor ¬q holds. (I do not know the exact way to say why, but I would guess that when neither □q nor □¬q holds, that means neither q nor ¬q holds, because we are assuming that q ⊨ □q and ¬q ⊨ □¬q are valid, which means that it cannot be that the premises are true but the conclusion false; and since the conclusion is false, it cannot be that the premises are true.)]

In fact, we can simplify the argument. Neither Tq nor the conditional is playing an essential role. We may run the argument as follows. If q were true, this would be a present fact, and so fixed; that is, it would be necessarily true, that is: q ⊨ □q. Similarly, if it were false, it would be necessarily false: ¬q ⊨ □¬q. Since neither □q nor □¬q holds, neither q nor ¬q holds.

(252)

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11a.7.6

[Using KK3]

 

[Aristotle does not allow exceptions to the Law of Non-Contradiction. So the sort of many-valued modal logic we use in application to his Future  Contingents argument should validate it. Thus we should not use KFDE or KLP but rather KK3, in which there is the option for formulas to be neither true nor false, but not the option for contradictions.]

 

[So recall that in KFDE neither the law of contradiction nor the law of excluded middle holds. When we apply the exhaustion constraint, (making it such that formulas must be either, true, false, or both) that validates excluded middle and gives us KLP (see section 11a.4.7). Or if we apply the exclusion constraint (making it such that formulas cannot be true, false, or neither), that validates non-contradiction and gives us KK3. Now, since we want to use a many-valued modal logic to understand Aristotle’s argument, and since {1} he does not allow the law of non-contradiction to be broken, (and {2} he seems to be thinking of a neither-value situation), we should not use KFDE or KLP but rather KK3.]

To do justice to Aristotle’s argument, we must take seriously the thought that some things might be neither true nor false. Since Aristotle does not countenance violations of the ‘Law of Non-Contradiction’, an appropriate logic is KK3 – or one of its normal extensions – not KFDE or KLP.

(252)

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11a.7.7

[The R Relation and the Persistence Constraint]

 

[In our many-valued modal logic, we indicate futurity with the R accessibility relation:“Think of the accessibility statement wRw′ as meaning that w′ may be obtained from w by some number (possibly zero) of further things happening” (252). Given the nature of time, R is reflexive and transitive but not symmetrical. To capture Aristotle’s assumption that “once something is true/false, it stays so,” we will use a modified heredity constraint called the Persistence Constraint: “for every propositional parameter, p, and world, w: If pρw1 and wRw′, pρw1 ; If pρ w0 and wRw′, pρ w0 .]

 

[Priest will now introduce our use of the accessibility relation R for our many-valued modal analysis of future contingents. Here it seems to intuitively mean something like the accessed world comes later in time, but it is worded more in term of events than temporal moments. So I am not sure how it differs from the R relation in the tense logic we saw (see section 3.6a.2). At any rate, this R relation is reflexive and transitive. (I suppose it would not be symmetrical given the arrow of time.) One of Aristotle’s assumptions is that “once something is true/false, it stays so” (Priest 252). Now recall from section 6.3.3 the heredity condition, which says that when a proposition is true in one world, it it is true in all other worlds that are accessible from it: “for every propositional parameter, p: for all wW, if vw(p) = 1 and wRw′, vw(p) = 1 ” (p.105 section 6.3.3). Priest now reformulates it for many-valued modal logic and calls it here the Persistence Constraint. (Maybe we can note that nothing is said for when things are neither-valued, and thus a valueless statement about a future contingent can later obtain the true or false value when that becomes determined.)]

Think of the accessibility statement wRw′ as meaning that w′ may be obtained from w by some number (possibly zero) of further things happening. Clearly, R is reflexive and transitive. According to Aristotle, once something is true/false, it stays so. We may capture the idea by the heredity condition: for every propositional parameter, p, and world, w:

If pρw1 and wRw′, pρw1

If pρ w0 and wRw′, pρ w0

| Call this the Persistence Constraint. The displayed conditions follow for all unmodalised formulas, as may be shown by an easy induction. (Details are left as an exercise.)

(252-253)

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11a.7.8

[The Non-Holding of the Persistence Constraint for Modalized Formulas]

 

[The persistence constraint does not hold for modalized formulas.]

 

[Priest next notes that the persistence constraint does not hold for modalized formulas. (I do not quite grasp the reasoning here, but I will work through it the best I can. Priest writes: “Let s be the sentence ‘It rains in St Andrews on 1/1/2100’. ◊s and ◊¬s are both true. But there is a possible world (indeed, a probable one!) in which s is true, and so □s is true, and ◊¬s is false.” My current (and likely mistaken) understanding is the following: when he writes, “so □s is true, and ◊¬s is false,” he means □s is true in this possible future world where it rains and ◊¬s is false in that world. But probably I am wrong. I will just make a diagram to show my understanding, and I will revise this later after I know better. I will use a sort of diagraming that was done in section 2.3.8. I will put aside the world reflexivity idea. Let us think of three moments. In the first moment, the future contingent s is not yet decided. I will put in brackets my own representation of that, even though it can simply be omitted probably. So at time 1 (T1), neither s nor its negation is true or false.

 

xxxT1

xxxxxxxxxxxxxx

xxxxxxxxxxxxxxxx

xxxw1

¬[sρ∅]

x[¬sρ∅]

 

In the next moment, T2, two possibilities can happen, either s or ¬s will be realized. We model that as two possible worlds accessible from the first.

x

xxxT1xxxxxxxxxxxxxxxT2

xxxxxxxxxxxxxxxxxxxxw2xxxxxxx

xxxxxxxxxxxxxxxxxxsρ1

xxxw1 xxxxxxxxxxxx¬sρ0

¬[sρ∅]xxxxxxxxxxx

x[¬sρ∅]xxxxxxxxxxxxxw3xxxxxxx

xxxxxxxxxxxxxxxxxxxxsρ0

xxxxxxxxxxxxxxxxxxx¬sρ1

x

And for clarity, let us assume that in each future alternative, that the persistence constraint holds and that future decided event stays as such.

x

xxxT1xxxxxxxxxxxxxxxT2xxxxxxxxxxxxxT3

xxxxxxxxxxxxxxxxxxxxw2xxxxxxxxxxxxw4xxxxxxx

xxxxxxxxxxxxxxxxxxsρ1xxxxxxxxxxxxsρ1

xxxw1 xxxxxxxxxxxx¬sρ0xxxxxxxxxxxx¬sρ0

¬[sρ∅]xxxxxxxxxxx

x[¬sρ∅]xxxxxxxxxxxxxw3xxxxxxxxxxxxxw5xxxxxxx

xxxxxxxxxxxxxxxxxxxxsρ0xxxxxxxxxxxxsρ0

xxxxxxxxxxxxxxxxxxx¬sρ1xxxxxxxxxxx¬sρ1

x

Since s is 1 in one possible world accessible to the first moment, and since it is 0 in another, we would seem to have these possibility values in world 1, time 1.

x

xxxT1xxxxxxxxxxxxxxxT2xxxxxxxxxxxxxT3

xxxxxxxxxxxxxxxxxxxxw2xxxxxxxxxxxxw4xxxxxxx

xxxxxxxxxxxxxxxxxxsρ1xxxxxxxxxxxxsρ1

xxxw1 xxxxxxxxxxxx¬sρ0xxxxxxxxxxxx¬sρ0

¬[sρ∅]xxxxxxxxxxx

x[¬sρ∅]xxxxxxxxxxxxxw3xxxxxxxxxxxxxw5xxxxxxx

xx◊sρ1xxxxxxxxxxxxxsρ0xxxxxxxxxxxxsρ0

xx¬sρ1xxxxxxxxxxxx¬sρ1xxxxxxxxxxx¬sρ1

x

So maybe that would show that “◊s and ◊¬s are both true”. The next part reads, “But there is a possible world (indeed, a probable one!) in which s is true, and so □s is true, and ◊¬s is false”. My best understanding of this so far is that this other possible world would be world 2 in the diagram. And maybe when he says, “so □s is true,” he means that in world 2 □s is true (and so we are not saying something here about world 1, I am guessing). In our diagram below, I added the additional world/moment to make it more visually apparent that once it happens to be so in world 2, it persists as true. And, since ¬s does not hold in moments after that, we have ◊¬s as false, too. So:

x

xxxT1xxxxxxxxxxxxxxxT2xxxxxxxxxxxxxT3

xxxxxxxxxxxxxxxxxxxxw2xxxxxxxxxxxxw4xxxxxxx

xxxxxxxxxxxxxxxxxxsρ1x;x□sρ1xxxxxxsρ1

xxxw1 xxxxxxxxxxxx¬sρ0x;x¬sρ0xxxxxx¬sρ0

¬[sρ∅]xxxxxxxxxxxx

x[¬sρ∅]xxxxxxxxxxxxxw3xxxxxxxxxxxxxw5xxxxxxx

xx◊sρ1xxxxxxxxxxxxxsρ0xxxxxxxxxxxxsρ0

xx¬sρ1xxxxxxxxxxxx¬sρ1xxxxxxxxxxx¬sρ1

xxxxxxxxxxxxxxxxxxx

Now, as far as I can understand, Priest’s point is that we can see here that the Persistence Constraint does not work for the modal operators, because ¬s holds as true in moment 1, but it holds as false in moment 2, world 2. (And we are assuming that it cannot be both in this sort of logic.) Or in other words, if the Persistence Constraint did hold, then ¬s should hold also in world two, but it does not.

x

xxxT1xxxxxxxxxxxxxxxT2xxxxxxxxxxxxxT3

xxxxxxxxxxxxxxxxxxxxw2xxxxxxxxxxxxw4xxxxxxx

xxxxxxxxxxxxxxxxxxsρ1x;x□sρ1xxxxxxsρ1

xxxw1 xxxxxxxxxxxx¬sρ0x;x¬sρ0xxxxxx¬sρ0

¬[sρ∅]xxxxxxxxxxxx

x[¬sρ∅]xxxxxxxxxxxxxw3xxxxxxxxxxxxxw5xxxxxxx

xx◊sρ1xxxxxxxxxxxxxsρ0xxxxxxxxxxxxsρ0

xx¬sρ1xxxxxxxxxxxx¬sρ1xxxxxxxxxxx¬sρ1

xxxxxxxxxxxxxxxxxxx

]

They do not hold for modalised formulas, however; nor would one expect them to. Let s be the sentence ‘It rains in St Andrews on 1/1/2100’. ◊s and ◊¬s are both true. But there is a possible world (indeed, a probable one!) in which s is true, and so □s is true, and ◊¬s is false.

(253)

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11a.7.9

[Logic A and the Success of Aristotle’s Argument]

 

[Our many-valued K3ρτ logic, augmented by the Persistence Constraint, is called A (for Aristotle). “In this logic p ⊨ □p and ¬p ⊨ □¬p. Aristotle’s argument therefore works. But, of course, in A, p ¬p may fail to be true.”]

 

[As we saw in section 11a.7.6 above, we are using a K3 logic, which means that you can have neither value but not both truth values. And we saw in section 11a.7.7 above that our R relation is reflexive and transitive, so that gives us K3ρτ. And also in that section 11a.7.7 above, we saw that our logic is augmented by the Persistence Constraint. Priest writes, “Call K3ρτ augmented by the Persistence Constraint, A (for Aristotle)” (253). (Note, the proper unicode symbol is not showing for me for some reason; so where I use this name for the Aristotle logic, A, the ‘A’ should look like this character, “Mathematical Bold Fraktur Capital A”.) As we saw in section 11a.7.5 above, for this logic of Aristotle, p ⊨ □p and ¬p ⊨ □¬p, because we cannot change what is true in the present, and thus it is necessary. Priest then gives a counter-model to show that p ¬p can fail when p is true in one future contingency and when ¬p is true in the other. Priest’s footnoted point is philosophically important but tricky for me to grasp. I cannot guess well enough at the moment what the issue is there, so I will come back to revise this. Priest writes: “Though one might object: the Persistence Constraint should hold only for those things that are genuinely about the present (w). (A sentence can be grammatically present but essentially about the future – such as the sentence ‘ “it will rain” is true’.) Enforcing the Persistence Constraint for those p that are covertly about the future may therefore be thought to be question-begging.” The only thing in my mind right now is that maybe it has something to do with what we said in section 11a.7.4 and section 11a.7.5 above. Priest wrote, “It is clear that he thinks that the past and present are fixed (unchangeable, now inevitable). So if s is a statement about the past or present, s ⊃ □s. Hence, Tq ⊃ □Tq, and since □(Tqq), so that □Tq ⊃ □q, it follows that Tq ⊃ □q. There is no fallacy here” (252, section 11a.7.4) and “If q were true, this would be a present fact, and so fixed; that is, it would be necessarily true, that is: q ⊨ □q. Similarly, if it were false, it would be necessarily false: ¬q ⊨ □¬q. Since neither □q nor □¬q holds, neither q nor ¬q holds” (252, section 11a.7.5). My best guess is that Priest in this footnote is making the following point, but I am just guessing here. We vindicate Aristotle by making his inference valid, which involves making presently true claims necessary. But, some might object that we can have something like q ⊨ □q only when q is about things of the present and not about the future. And so, when q does happen to be about the future, when we infer q ⊨ □q, we are incorrectly thinking that a statement about a future contingent can have a truth value that persists and thus cannot be otherwise in the future and thus is necessary now. So maybe by inferring q ⊨ □q now, we are begging the question in the sense that we are claiming something is going to happen when in fact its going-to-happen is not established right now. At any rate, I will work on this later.]

Call K3ρτ augmented by the Persistence Constraint, A (for Aristotle). In this logic p ⊨ □p and ¬p ⊨ □¬p. Aristotle’s argument therefore works. But, of course, in A , p ¬p may fail to be true. Here is a simple counter-model (I omit the arrows of reflexivity):

x

xxxxxxxxxxxxxxxxxxxxxw1xxx+p

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

–p  ;  ¬p  xw0

xxxxxxxxxxxxxxxxxx

xxxxxxxxxxxxxxxxxxxxxw2xxx+¬p

xxxxxxxxxxxxxxxxxxxx

Aristotle is vindicated.3

(253)

3. Though one might object: the Persistence Constraint should hold only for those things that are genuinely about the present (w). (A sentence can be grammatically present but essentially about the future – such as the sentence ‘ “it will rain” is true’.) Enforcing the Persistence Constraint for those p that are covertly about the future may therefore be thought to be question-begging.

(253)

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11a.7.10

[A Missing Notion in Logic A]

 

[For our Aristotle logic A, neither □p not □¬p holds. However, Aristotle thinks that eventually p or ¬p will have to hold, thus he thinks □(p ¬p). Yet, this does not hold in logic A.]

 

[Recall from section 7.10.2 that Aristotle would not want all statements to be valueless, and he would want the law of excluded middle to hold when the future events happen, even if statements about future contingents would be valueless before that time. So while neither □p not □¬p holds for Aristotle, □(p ¬p) does. (In other words, given some statement about a future contingent, as it can be otherwise than what is stated, we cannot say that it is necessarily so nor can we say it is not. However, we can say that when that event is to happen, either it or its negation must happen, thus □(p ¬p).) Nonetheless, □(p ¬p) is not valid in A.]

Matters are a little more difficult than this, however, as we noted in 7.10.2. Later in the same chapter Aristotle says:4

A sea fight must either take place tomorrow, or not; but it is not necessary that it should take place tomorrow, neither is it necessary that it should not take place, yet it is necessary that it either should or should not take place tomorrow.

He is saying that, for the appropriate p, we have neither □p not □¬p. We still have □(p ¬p), however. As is easy to see, □(p ¬p) is not valid in A.

(253)

4. De Int. 19a30–32.

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11a.7.11

[Using Complete Worlds to Remedy the Problem with Logic A]

 

[To allow □(p ¬p) to hold in logic A, we can take a temporal perspective of the end of time when everything has been decided. “Call a world complete if every propositional parameter is either true or false. A natural way of giving the truth conditions for □ is as follows:  □Aρw1 iff for all complete w′ such that wRw′, Aρw′1 ;

Aρw0 iff for some complete w′ such that wRw′, Aρw′ 0 . The truth/falsity conditions for ◊ are the same with ‘some’ and ‘all’ interchanged. □A may naturally be seen as expressing the idea that A is inevitable. [...] for any complete world, w, Persistence holds for all formulas. It follows that at such a world, A is true iff □A is, and that all formulas are either true or false” (254).]

 

[Priest next gives a remedy for the problem mentioned above in section 11a.7.10, namely, that □(p ¬p) should hold. We first consider a temporal perspective where everything has happened, and thus all truth-values for p have been decided. We call such a world complete when all its propositional parameters are either true or false. We then say that a formula with the necessity operator is true in a world only if for all complete worlds accessible from it that formula is true. I would assume then that we would have □(p ¬p) being true in all evaluations, since every complete world would have either p or ¬p hold eventually. We can get the possibility true/false conditions by using the word “some”. So when we have □A, that means it is inevitable. And in a complete world, persistence holds and “A is true iff □A is.”]

The matter may be remedied by modifying the truth conditions for □. Though neither p nor ¬p may be true at a world, w, it is natural to suppose on the Aristotelian picture that the truth value of p will eventually be decided. We may therefore view things ‘from the end of time’, when everything undetermined has been resolved. Call a world complete if every propositional parameter is either true or false. A natural way of giving the truth conditions for □ is as follows:

Aρw1 iff for all complete w′ such that wRw′, Aρw′1

Aρw0 iff for some complete w′ such that wRw′, Aρw′ 0

The truth/falsity conditions for ◊ are the same with ‘some’ and ‘all’ interchanged. □A may naturally be seen as expressing the idea that A is inevitable. It is not difficult to show that, for any complete world, w, Persistence holds for all formulas. It follows that at such a world, A is true iff □A is, and that all formulas are either true or false. (Details are left as an exercise.)

(254)

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11a.7.12

[The Success of Modified Logic A]

 

[These above revised truth/falsity conditions for necessity allow us to capture the important assumptions and valid inferences in Aristotle’s argumentation regarding future contingency, namely: “p ⊨ □p, ¬p ⊨ □¬p (so Aristotle’s argument still works), ⊨ □(p ∨ ¬p), but not ⊨ □p ∨ □¬p” (254).]

 

[Priest lastly shows how these modified necessity conditions allow us to more completely model Aristotle’s thinking on future contingency. Recall from above, for example from section 11a.7.5, that Aristotle’s argument requires the inferences q ⊨ □q and ¬q ⊨ □¬q. The above necessity conditions produce this: p ⊨ □p, and ¬p ⊨ □¬p. So Aristotle’s controversial inference would be valid here. We saw above in section 11a.7.11 that ⊨ □(p ∨ ¬p) holds. And finally, ⊨ □p ∨ □¬p also holds. (I did not follow the reasoning. See the quotation below.)]

With the revised truth/falsity conditions for □, p ⊨ □p, ¬p ⊨ □¬p (so Aristotle’s argument still works), ⊨ □(p ∨ ¬p), but not ⊨ □p ∨ □¬p. For the first of these, if p is true at w then, by the Persistence Constraint, p holds at any complete world accessed by w. Hence □p is true at w. The argument for the second is similar. For the third, in any complete world accessed by w, either p or ¬p holds. Hence p ∨ ¬p holds, and □(p ∨ ¬p) is true at w. (Indeed, the same holds for an arbitrary formula, A.) For the last, consider the interpretation of 11a.7.9. We may suppose that all the parameters other than p also take a classical value at w1 and w2, and hence that these worlds are complete. Neither □p nor □¬p is true at w0.5

(254)

5. What one loses on this account is, of course, the validity of the inference from □A to A, even though the accessibility relation is reflexive. The inference is guaranteed to preserve truth only at complete worlds.

(254)

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From:

 

Priest, Graham. 2008 [2001]. An Introduction to Non-Classical Logic: From If to Is, 2nd edn. Cambridge: Cambridge University.