Showing posts with label Leibniz' Calculus Explanation. Show all posts
Showing posts with label Leibniz' Calculus Explanation. Show all posts

22 Apr 2014

Katz and Sherry’s [Pt.4.6] “Leibniz’s Infinitesimals: Their Fictionality, Their Modern Implementations, And Their Foes From Berkeley To Russell And Beyond,” 4.6 ‘Assignable Versus Unassignable’, summary


summary by Corry Shores
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Mikhail G. Katz  and David Sherry


“Leibniz’s Infinitesimals: Their Fictionality, Their Modern Implementations, And Their Foes From Berkeley To Russell And Beyond”


4. Cum Prodiisset


 

4.6 Assignable Versus Unassignable



Brief Summary:

In Cum Prodiisset Leibniz works with assignable (finite) and unassignable (infinitesimal / infinite) values. On account of his law of continuity, we can use the same mathematical operations even when we substitute one for the others.


Summary

 

Leibniz’ infinitesimal values dx and dy are ‘unassignable,’ and Leibniz writes that

the unassignables dx and dy may be substituted for them by a method of supposition even in the case when they are evanescent (Child [Leibniz] 1920, p. 153).
[KS 583]

KS will examine Leibniz’ multiplicative example:

ay = xv

[We will look briefly at Leibniz’ procedures to follow Katz and Sherry. Leibniz writes: “Let ay = xv, then a(d)y = x(d)v + v(d)x.” Leibniz then adds to their corresponding values dy, dx, and dv:

Proof. ay + ady = (x + dx) (v+ dv) “

then expanding

= xv + xdv + vdx +dxdv.

And so together:

ay + ady = (x + dx) (v+ dv) = xv + xdv + vdx +dxdv

or

ay + ady = xv + xdv + vdx +dxdv

(note: there is a transcription error in the translation. In the following, the original has ‘xv’ but the translation has instead ‘xy’.)

We then remove ay and xy (perhaps because they are repeated now in their infinitesimal renditions)

ady = xdv + vdx + dxdv

(then dividing both sides by dx)

image

This is the formulation KS move next to.]

“Simplifying the differential quotient, Leibniz obtains”

image

[It seems then that Leibniz will replace the infinitesimals dy and dx with finite differences (d)y and d(x), but he will not do the same for the second d(v) for some reason, leaving it as infinitesimal. Returning to KS:]

At this point Leibniz proposes to transfer ‘‘the matter, as we may, to straight lines that never become evanescent’’, obtaining

image

KS explain that (d)y and (d)x are assignable, while dv is ‘superfluous’ as ‘it alone can be evanescent’ [KS 583, quoting Leibniz].

[This means that dv can be treated as zero and removed from the equation. Then, we multiple both sides by (d)x to obtain:

image

Then Leibniz divides both sides by a and by (d)x to obtain:

image

Then Leibniz notes that (d)y / (d)x “always” equals dy/dx. Thus we can substitute them. This is an application of the principle of continuity again:

Also, since (dy) : (d)x always = dy : dx, it will be allowable to suppose this is true in the case when dy, dx become evanescent, and to say that dy : dx = x + v : a, or ady = xdv + vdx.
(Leibniz 154)

(above by multiplying both sides by a and dx).]

But the law of homogeneity is not mentioned here in Cum Prodiisset, so we do not here have sufficient rational for that step in the operation.

The authors then show a case in the Leibniz text of division by second differentials, which they say is incompatible with the nilsquare approach. [The author’s mention the nilsquare approach in section 4.1]


Bibliography:

Katz, M.; Sherry, D. Leibniz's Infinitesimals: Their Fictionality, Their Modern Implementations, And Their Foes From Berkeley To Russell And Beyond. Erkenntnis 78 (2013), no. 3, 571-625. See http://dx.doi.org/10.1007/s10670-012-9370-y, http://www.ams.org/mathscinet-getitem?mr=3053644, and http://arxiv.org/abs/1205.0174


The above bibliography material taken from the following source, a page by Mikhail Katz, which links to many other recent publications on infinitesimals.

http://u.cs.biu.ac.il/~katzmik/infinitesimals.html

Regarding the Leibniz text:

English references from:

Leibniz. The Early Mathematical Manuscripts of Leibniz. Trans. J.M. Child. Mineola, NY: Dover, 2005 [1920 Open Court].
1920 Edition available at archive.org:
https://archive.org/details/earlymathematic01gerhgoog


Latin references from:

Leibniz. Historia et origo calculi differentialis. Ed. C.I. Gerhardt. Hannover: Im Verlage der Hahn'schen Hofbuchhandlung, 1846]
Available at archive.org:
https://archive.org/details/historiaetorigo00gerhgoog




20 Apr 2014

Examples of Status Transitus / Status Terminus and the Law of Continuity in Leibniz’ Cum Prodiisset


summary by Corry Shores
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[The following is summary. My own comments and citations are placed in double brackets. All boldface and underlying are mine.]




 

Leibniz

 

Examples of Status Transitus / Status Terminus and the Law of Continuity in


 Cum Prodiisset


 



Brief Summary:

In Cum Prodiisset Leibniz discusses his Law of Continuity. According to one formulation, in a continuous transition, the final ending (the terminus) of the transition may be included with that transition. He provides a number of examples to illustrate. They show changes from opposing states happening continuously and by means of an infinitesimally small variation, for example, unequal and equal, motion and rest, convergent and parallel, and enclosed and open. On account of the law of continuity, the same calculatory procedures apply both when the values are finite and also as they pass into the infinite.


Summary

 

Before giving his examples of status transitus [/status terminus] (a concept bound up with his law of continuity), he first formulates it thus:

In any supposed transition, ending in any terminus, it is permissible to institute a general reasoning, in which the final terminus may also be included. [Leibniz 147]

 

[[See especially Katz and Sherry’s discussion of this text, section 4 of “Leibniz’ Infinitesimals”]] Leibniz will repeat this idea of ‘a general reasoning’ for his examples. One of them involves calculations, so we will skip first to that one to gain a more technical understanding of the term. [The following, up to ‘Example 1’ is quotation except for material in double brackets. The main idea we will obtain is that a general reasoning allows the same calculating procedures to continue even after values shift from finite to infinitesimal.]


First of all, the sense in which the phrase "dy is the element of y," is to be taken will best be understood by considering a line A  referred to a straight line AX as axis.

Leibniz parabola tangent B

Let the curve AY be a parabola,

Leibniz parabola tangent B.1

and let the tangent at the vertex A be taken as the axis. [[Note, the Latin original indicates the axis as AX: et assumtos Axis AX sit tangens parabolae in vertice A. (p.44)]]

Leibniz parabola tangent B.2

If AX is called x,

Leibniz parabola tangent B.3

and AY, y,

Leibniz parabola tangent B.4

[[given the way that dy is defined below, y could instead be the distance from A to Y, when Y is understood as a vertical axis.

Leibniz parabola tangent B.10

]]

and the latus-rectum is a [[the latus-rectum is often defined as the line going through the focus, perpendicular to the axis, with endpoints on the parabola. It does not seem to be shown here]], the equation to the parabola will be xx = ay, and this holds good at every point. Now, let A1X= x,

Leibniz parabola tangent B.9

and 1X1Y = y

Leibniz parabola tangent B.5

and from the point 1Y let fall a perpendicular 1YD to some greater ordinate 2X2Y that follows,

Leibniz parabola tangent B.6

and let 1X2X, the difference between A1X and A2X, be called dx;

Leibniz parabola tangent B.7

and similarly, let D2Y, the difference between 1X1Y and 2X2Y, be called dy.

Leibniz parabola tangent B.8

Then, since y = xx: a, by the same law,

[[

xx = ay
xx / a = ay / a
xx /a = y
y = xx / a

]]

we have

y+ dy = xx + 2xdx + dxdx, : a ;

[[regarding the above: since we are adding dy to y, perhaps then the other side needs to be (x + dx)(x + dx), because we would be adding dx to both x’s just as we add dy to all cases of y. Then we would obtain the above formulation by expanding it.]]

and taking away the y from the one side and the xx: a from the other, we have left

dy: dx = 2x + dx : a ;

[[It seems we can remove the y = xx / a, perhaps because the same formulation repeats with the dy and dx. That leaves us with:

dy = (2xdx + dxdx) / a ;

Then we move a dx to the other side:

dy / dx = (2xdx + dxdx) / dx(a)

Producing the formula again:

dy / dx = 2x + dx / a

]]

and this is a general rule, expressing the ratio of the difference of the ordinates to the difference of the abscissae, [[the formulation y = xx / a gave us the relation of the ordinates to the abscissae. Then we reformulated it to give us the relation between the differences of the abscissae and ordinate by means of dy and dx.]]

or, if the chord 1Y2Y is produced until it meets the axis in T,

Leibniz parabola tangent B.12

then the ratio of the ordinate 1X1Y to T1X, the part of the axis intercepted between the point of intersection and the ordinate, will be as 2x+ dx to a. Now, since by our postulate it is permissible to include under the one general reasoning the case also in which the ordinate 2X 2Y is moved up nearer and nearer to the fixed ordinate 1X 1Y until it ultimately coincides with it, it is evident that in this case dx becomes equal to zero and should be neglected, and thus it is clear that, since in this case T1Y is the tangent, 1X1Y is to T1X as 2x is to a.

Leibniz parabola tangent animation 3

[[Leibniz then seems to state that what he means with the law of continuity is that we can regard as equivalent cases both with evanescent values and with them removed.]]

Hence, it may be seen that there is no need in the whole of our differential calculus to say that those things are equal which have a difference that is infinitely small, but that those things can be taken as equal that have not any difference at all, provided that the calculation is supposed to be general, including both the cases | in which there is a difference and in which the difference is zero; and provided that the difference is not assumed to be zero until the calculation is purged as far as is possible by legitimate omissions, and reduced to ratios of non-evanescent quantities, and we finally come to the point where we apply our result to the ultimate case.

[[Thus to ‘include under one general reasoning seems to mean in this case that we consider the formula for the parabola as holding for all values of 1Y2Y, including when that value vanishes to zero. Perhaps then in the examples that precede this one in the text, which we will discuss below, ‘under one general reasoning’ might as well mean that whatever formula we regard as applying in the finite cases as well apply in the infinitesimal case.]]

” [The above quoted material from Leibniz 151-152]



Example 1:

We consider quantities A and B, where B is larger than A. However, A is diminishing until equaling B. Nonetheless, we can include its value at B as belonging in unbroken continuum with the prior values, even though their states are contrary [[when vanishing to B, A is both equal and unequal to B]]. Here is the passage as quotation:

if A and B are any two quantities, of which the former is the greater and the latter is the less, and while B remains the same, it is supposed that A is continually diminished, until A becomes equal to B ; then it will be permissible to include under a general reasoning the prior cases in which A was greater than B, and also the ultimate case in which the difference vanishes and A is equal to B. [Leibniz 147]


Example 2:

Consider two bodies in motion, A and B. A’s velocity is continuously diminishing to zero (rest) all while B’s remains the same. Even though A’s motion is coming to a rest, we can include all its variations in speed, including its coming-to-rest state, with B’s motion. [[See quoted text below. Perhaps we are to think of A and B as beginning at the same speed, so to both illustrate the continuity of change with the dichotomy of states, motion and rest]]

Similarly, if two bodies are in motion at the same time, and it is assumed that while the motion of B remains the same, the velocity of A is continually diminished until it vanishes altogether, or the speed of A becomes zero ; it will be permissible to include this case with the case of the motion of B under one general reasoning. [Leibniz 147]


Example 3:

image

Consider of we have a line converging with another at some angle. We pivot the line on some fixed point (P above), extending the line so that it continues to converge with the other line. The angle continuously diminishes. When it reaches the infinitely small, the lines are becoming parallel. Even though the line’s position is discontinuous, this transition is included with all prior ones.

Leibniz parallel lines animation 6

[Animated diagram by Corry Shores, using OpenOffice Draw and Unfreez]



From the translation:

We do the same thing in geometry, when two straight lines are taken, produced in any manner, one VA being given in position or remaining in the same site, the other BP passing through a given point P, and varying in position while the point P remains fixed ; at first indeed converging toward the line VA and meeting it in the point C ; then, as the angle of inclination VCA is continually diminished, meeting VA in some more remote point (C), until at length from BP, through the position (B)P, it comes | to βP, in which the straight line no longer converges toward VA, but is parallel to it, and C is an impossible or imaginary point. With this supposition it is permissible to include under some one general reasoning not only all the intermediate cases such as (B)P but also the ultimate case βP. [Leibniz trans 147. Above case of  “as the angle of inclination VCA is continually diminished” should have BCA instead, “deinde si angulus inclinationis, ut BCA continue minuatur” ]


Example 4:

Consider an ellipse. One focus moves away from other. In the infinitesimally small movement from finite to infinitely far, the figure changes from ellipse to parabola, and thus from enclosed to open.

Leibniz ellipse to parabola animation 2

[Animated diagram by Corry Shores, using OpenOffice Draw and Unfreez]

From the text:

Hence also it comes to pass that we include as one case ellipses and the parabola, just as if A is considered to be one focus of an ellipse (of which V is the given vertex), and this focus remains fixed, while the other focus is variable as we pass from ellipse to ellipse, until at length (in the case when the line BP, by its intersection with the line VA, gives the variable focus) the focus C becomes evanescent73 or impossible, in which case the ellipse passes into a parabola. Hence it is permissible with our postulate that a parabola should be considered with ellipses under a common reasoning. [ft 73: “ The term is here used with the idea of "vanishing into the far distance." ”]Just as it is common practice to make use of this method in geometrical constructions, when they include under one general construction many different cases, noting that in a certain case the converging straight line passes into a parallel straight line, the angle between it and another straight line vanishing. [Leibniz 148]

Leibniz continues, refering to these examples:

Moreover, from this postulate arise certain expressions which are generally used for the sake of convenience, but seem to contain an absurdity, although it is one that causes no hindrance, when its proper meaning is substituted. For instance, we speak of an imaginary point of intersection as if it were a real point, in the same manner as · in algebra imaginary roots are considered as accepted numbers. Hence, preserving the analogy, we say that, when the straight line BP ultimately becomes parallel to the straight line VA, even then it converges toward it or makes an angle with it, only that the angle is then infinitely small; similarly, when a body ultimately comes to rest, it is still said to have a velocity, but one that is infinitely small ; and, when one straight line is equal to another, it is said to be unequal to it, but that the difference is infinitely small ; and that a parabola is the ultimate form of an ellipse, in which the second focus is at an infinite distance from the given focus nearest to the given vertex, or in which the ratio of PA to AC, or the angle BCA, is infinitely small. [Leibniz 148]


Bibliography:

English references from:

Leibniz. The Early Mathematical Manuscripts of Leibniz. Trans. J.M. Child. Mineola, NY: Dover, 2005 [1920 Open Court].

1920 Edition available at archive.org:

https://archive.org/details/earlymathematic01gerhgoog


Latin references from:

Leibniz. Historia et origo calculi differentialis. Ed. C.I. Gerhardt. Hannover: Im Verlage der Hahn'schen Hofbuchhandlung, 1846]

Available at archive.org:

https://archive.org/details/historiaetorigo00gerhgoog


The above bibliography material taken from the following source, a page by Mikhail Katz, which links to many other recent publications on infinitesimals.

http://u.cs.biu.ac.il/~katzmik/infinitesimals.html

13 Apr 2014

Katz and Sherry’s [Pt.3] “Leibniz’s Infinitesimals: Their Fictionality, Their Modern Implementations, And Their Foes From Berkeley To Russell And Beyond,” 3 ‘A Pair of Leibnizian Methodologies, summary


summary by Corry Shores
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Mikhail G. Katz  and David Sherry


“Leibniz’s Infinitesimals: Their Fictionality, Their Modern Implementations, And Their Foes From Berkeley To Russell And Beyond”


3. A Pair of Leibnizian Methodologies


Brief Summary:

Leibniz had two methodologies, which the authors call the A-methodology (using Archimedes’ exhaustion) and the B-methodology (using infinitesimals). Recent Leibniz scholars either acknowledge both of Leibniz’ methodologies or just the first type. The authors believe those in the second camp are misreading Leibniz’ notion of the infinitesimal’s fictionality.


Summary


Leibniz had two infinitesimal calculus methodologies: one by exhaustion and one using the law of continuity. (KS 575) The first relies on Archimedes’ exhaustion method, and the authors call it the ‘A-methodology’. The second uses infinitesimals and is called the ‘B-methodology’.


Leibniz considered infinitesimals as fictions. In his time, this was a controversial position, especially for some of his disciples, like Bernoulli, l’Hôpital, and Varignon. Accordiing to Ferraro, “Leibniz’s infinitesimals enjoy an ideal ontological status similar to that of the complex numbers, surd (irrational) exponents, and other ideal quantities.” (576)


The authors will now examine how commentators attribute either both A and B methodologies or just the A-methodology. They first quote from Leibniz’ 1702 letter to Varignon.

Here Leibniz outlines a geometrical argument involving quantities c and e described as ‘‘not absolutely nothing’’, and goes on to comment that c and e [KS quoting Leibniz:]

are treated as infinitesimals, exactly as are the elements which our differential calculus recognizes in the ordinates of curves for momentary increments and decrements (Leibniz et al. 1702, pp. 104–105). [KS 576]

Jesseph argues that Leibniz proposes both A and B methodologies. Like Bos, Jesseph emphasizes Leibniz’ law of continuity and regards it not as a mathematical principle but rather as a “a general methodological rule with applications in mathematics, physics, metaphysics, and other sciences’’ (KS 576 quoting Jesseph ibid p.21).


Recent work on Leibniz’ calculus is divided into two camps: 1) Those who recognize both methodologies (Bos, Ferraro, Horváth, Jesseph, and Laugwitz), and 2) those who have a syncategorematic interpretation that only recognizes the A-methodology. The authors believe that the second reading “is due to an incorrect analysis of Leibniz’s fictionalism.” (KS 577)



Bibliography:

Katz, M.; Sherry, D. Leibniz's Infinitesimals: Their Fictionality, Their Modern Implementations, And Their Foes From Berkeley To Russell And Beyond. Erkenntnis 78 (2013), no. 3, 571-625. See http://dx.doi.org/10.1007/s10670-012-9370-y, http://www.ams.org/mathscinet-getitem?mr=3053644, and http://arxiv.org/abs/1205.0174


The above bibliography material taken from the following source, a page by Mikhail Katz, which links to many other recent publications on infinitesimals.

http://u.cs.biu.ac.il/~katzmik/infinitesimals.html

4 Jul 2012

Difference & Sensation: Deleuze's Spinozistic Affect


by Corry Shores
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The following is my presentation at the Nederlands Genootschap voor Esthetica (Dutch Association of Aesthetics) Utrecht Expertmeeting Kunstfilosofie in Utrecht, November 2011


Corry Shores

Difference & Sensation:
Deleuze's Spinozistic Affect



Photobucket
(Animation above is my own, made with GIMP and Unfreeze,
image from Spinoza, Opera vol. 2, archive.org
, p.233)

Deleuze is commonly considered an anti-phenomenologist. However, I would like to explore the phenomenological value of his aesthetical ideas regarding affection and bodily sensation. The aim of this presentation is to offer a Spinozistic interpretation of certain concepts in Deleuze’s Francis Bacon book. For this aim, I draw primarily upon Deleuze’s writings on Spinoza’s affection. We will regard affection phenomenologically as involving a sort of affective awareness of bodily-given phenomena. We do this because Deleuze explains Spinoza’s kinds of knowledge in terms of the rhythm of affection.

Deleuze specifically refers to affective awareness as ‘the phenomenon of passage.’ It is the lived transition that we undergo when affections transfer us from one bodily state to another.


There are two primary dimensions, then, to such affective alterations.

One is the physical composition of bodies that becomes changed by the affection. The other is the dynamic of the alteration. Deleuze combines these two dimensions of affection, the compositional and the dynamic, by analyzing two sorts of infinities in Spinoza’s theory of affection, namely, extensive and intensive infinities. There is a cryptic diagram in Spinoza’s Twelfth Letter: the ‘letter on infinity.’ Deleuze’s novel interpretation of the diagram shows how it illustrates the two infinities.


Spinoza writes of the diagram that “all the inequalities of the space lying between the two circles ABCD in the diagram exceed any number, as do all the variations of the speed of matter moving through that area.”


We find similar diagrams in Spinoza’s Principles of Cartesian Philosophy. In the left diagram, both semi-circles share the same center. The space between their circumferences is everywhere the same. However, if the semi-circles do not share the same center, then the space between their circumferences will be everywhere unequal.


He also has us consider the circulation of water moving through the space between offset circles. And on account of the geometry of the non-concentric circles, every place along the circuit has a different width and hence “the fluid body that moves through the tube ABC receives an indefinite number of degrees of speed.”

The infinity diagram would then seem to be a hybrid of these two other figures.


Yet, Spinoza explains in his 81st letter that the infinity here is not obtained from the fact that there are more parts than can be counted. Instead, the diagram according to Deleuze, illustrates a mode’s infinite division into differential relations between infinitely small partitions.

Now, although Spinoza’s ‘letter on the infinite’ predates the inception of differential calculus, Deleuze locates in it what he considers to be seminal calculus notions. To explain the concept of infinitely small vanishing values, Deleuze guides us through the remarkably simple and illuminating visualization in one of Leibniz’ letters.


The diagonal line moves to the right, which diminishes the top triangle, all while increasing the bottom one; yet, because the triangles stay proportionally similar throughout the alteration, the ratio between the smaller one’s legs always remains proportional to the ratio between the larger one’s legs.


Photobucket
(Animation above is my own, made with OpenOffice Draw and Unfreeze)

The vanished triangle, Deleuze says, is not actually there, but is there “virtually,” because the vanishing lines have not yet entirely merged together at the corner. So the infinitely small legs of the smaller triangle are still distinct from each other and from the corner they are collapsing upon; and yet, they also do not extend beyond it. Thus, they do not bear extensive magnitudes but rather only intensive ones, which we will treat as degrees of variation. The philosophical idea here – difference without terms – is essential to Deleuze’s Spinozistic notion of affection. And it will allow us to see how Deleuze can use Spinoza’s diagram to illustrate both the intensive and extensive infinities that are involved in affection.

Photobucket
(Thanks en.wikipedia.org/ A.Greg)

Extensive bodies, for Spinoza, are divisible until reaching what he calls simplest bodies. Simplest bodies form compounds when ones moving at the same or at different speeds maintain a fixed relation in their mutual motions and when “the laws or nature of one part adapts itself to the laws or nature of another part in such wise that there is the least possible opposition between them.”

These infinitely small simplest bodies are never found alone, but rather only in infinite sets. These sets reciprocally unite with other infinite sets to compose a more complex body. These compound bodies are then combined with other bodies, and so on to higher orders until reaching the whole of Nature.

Photobucket
pulsing blue balls animated gif
heart cell beating
circulatory system pulsing beating pumping animated gif
circulatory system animation
Egypt protest bridge animated gif
amazon river animated gif
earth from space animated gif
solar system gif
spiral galaxy animated gif
galaxies animated gif


(Credits in order)
(colliding particles: Thanks A.Greg / en.wikipedia.org)
(blue molecule: Thanks M.L. Rahman / faculty.bracu.ac.bd)
(heart cell: Thanks Bluegrass Pundit / scinewsblog)
(heart beating: Thanks Sterile Barrier Solutions / sbsmed.net)
(circulatory system: Thanks John U / quietmoment.org)
(Egypt bridge protest: Thanks Freemanfilmsuk / youtube.com)
(Amazon river: Thanks BestofAttenborough /youtube.com)
(earth: Thanks UweTube / youtube.com)
(solar system: Thanks animated-sun.weebly.com)
(spiral galaxy: Thanks Kanal von beltoforion1 /youtube.com)
(galaxies: Thanks BrainMind.com / youtube.com)

In his letter on blood, Spinoza has his correspondent imagine a tiny worm so small that it can swim through the blood and observe how its tiniest particles collide and communicate their motion. The worm would see that the simple bodies of blood, the lymph and chyle, continually affect one another’s speeds. Yet, because they maintain their mutual affections without one destroying the other, they together make up the composite body that is our blood. The ratio of their speeds is a level of power that must stay within certain limits.


For otherwise, the simple bodies could decompose and enter into other relations. This happens, for example, when arsenic enters the blood. They will not combine. Rather, on account of their incompatible levels of power, arsenic will decompose our blood.

This sends a chain reaction of affective shockwaves throughout the body, decomposing all the other higher orders of differentially related parts. If it decreases our whole body’s power below a certain threshold, we die. Our body no longer expresses our modal essence, but instead its rearranged parts express the essences of other modes, such as the worms and soil we recompose into.

Thus, Deleuze interprets the infinity diagram as showing how a finite body extending between the limits of its size is divisible into an infinity of simplest bodies.

Photobucket
(Animation above is my own, made with GIMP and Unfreeze,
image from Spinoza, Opera vol. 2, archive.org, p.233)


Now to understand intensive infinities, first consider a ball on a chain swung in a circle. There are competing forces acting on the ball: on the one hand, it wants to fly outward, but on the other hand, its chain pulls it inward. As a result, the ball is always tending to go some certain way at each moment in its circular motion. If we were to cut the ball loose, it would not fly-off in a spiral, but instead outward in a straight line. This would also be the tangent to a circle’s curve at that point.
Photobucket
(Animation above is my own, made with OpenOffice Draw and Unfreeze)

The tangent on curves is like a tendency in the line’s change of direction at that place that is only implied in the movement. Physicists use techniques to find the instantaneous velocity of a moving object; it is something like the speed it is tending to go at that moment.


But how can a velocity be instantaneous? Well, nonetheless, it is a real quantity in the physical world, although it exists only as a virtuality.

Now, for a curve moving in a somewhat more irregular path, finding its tendency-toward-change is more complex, and here is where we might use Leibniz’ method.

Photobucket
(Animation above is my own, made with OpenOffice Draw and Unfreeze)

Photobucket
(Thanks Dr. Siddique / faculty.uncfsu.edu)

Sometimes we can almost feel where a certain part of the curve is heading just by judging its pattern of change. We can also create a triangle showing how the curve’s dimensions extend in a certain region. Then, like with Leibniz’ triangles, we slowly diminish the two triangle legs, and the third diagonal side gives us the tangent, which also tells us which way the curve is tending at that place.

Now, when sets of simplest bodies affectively impact the parts of our own bodies, their shocking collision corresponds with the production of an idea of that object in our imagination. “I look at the sun,” says Deleuze, “and the sun little-by-little disappears and I find myself in the dark of night; it is thus a series of successions, of coexistences of ideas, successions of ideas.” These ideas also correspond to an increase or decrease in our power of acting, and the variations are continuous.

He has us imagine that we encounter on the street our enemy Peter who makes us afraid. Yet, we suddenly turn our glance toward our friend Paul, whose charm reassures us. While moving from the ideas of Peter to Paul, we underwent a continuous increase in our power of action. These variations, Deleuze explains, are ever-altering quantities: “In other words, there is a continuous variation in the form of an increase-diminution-increase-diminution of the power of acting or the force of existing of someone according to the ideas which she has,” and “this kind of melodic line of continuous variation will define affect.”

In the 22nd letter, we find “nothing else pertains to an essence than that which it possesses at the moment it is perceived.” Deleuze reinterprets this as, “there belongs to an essence only the present, instantaneous affection that it experiences.” Deleuze offers an example of this instantaneity of an affective alteration.


We are meditating in a dark room. Then without warning, someone enters the room and abruptly turns on the lights, which completely dazzles us and renders us no longer able to maintain mental focus.

We pass between two very different states in a “lightning fast” alteration: “Two successive affections, in cuts. The passage is the lived transition from one to the other.” Every passage between affections is then necessarily an increase of power or a decrease of power. So if instead we are looking for our glasses in the complete dark, and then someone turns on a dim light, we appreciate him, because then the light increased our power of action. What we note here especially is that the affection’s increase or decrease is seen as instantaneous, which means it does not extend in time. Rather, it is an intensity.

Hence Deleuze’s other illustrative use of the diagram. A body has a certain range of affective power, and when an affection takes it beyond its limits, the body’s parts decompose into other bodies, like when arsenic enters the blood. So consider how there is a largest and smallest limit in the diagram, and throughout it is a continuum of an infinity of differential variations. Deleuze has us conceive this range of variation as representing the range of affective power that we can sustain before we decompose. So this is the intensive infinity.

Photobucket
(Animation above is my own, made with GIMP and Unfreeze,
image from Spinoza, Opera vol. 2, archive.org, p.233)


Now, according to Deleuze, we obtain Spinoza’s second kind of knowledge through our interactive contact with affecting bodies. As we saw with arsenic, the affections of other bodies can decompose us. Yet, in many cases when we are threatened by certain affections, we might know how to modify our own bodies so that we may sustain ourselves.

Deleuze cites an example in Dante’s Inferno. A damned soul is pelted with rain. Yet, rather than let the rain destroy him, he continually modifies the relations of his own body’s parts by twisting around, so that he may co-sustain with the rain’s affections. By making changes in the relations of our body-parts, we send waves of affective alteration throughout us on the level of our simplest bodies.


These internal self-affective shock-waves are in a dance of sorts with the external waves of affection, and their perpetuated interaction is what Deleuze here calls “rhythm.” Another example he offers is swimming. While in the water, a wave draws near us. When it strikes, we and the wave affect each other’s simplest-body arrangements. In that very instant we might be learning how to adjust to the wave’s decompositional forces. By modifying our own body’s composition, we may stay afloat and swim in conjunction with the wave, causing our body and the wave to become a compound, a larger body.

Another illustration better expresses how the rhythm of affection is a matter of differential relations. Deleuze explains that a violin and a piano playing independently do not really produce affective rhythm. However, they may achieve a rhythmic relationship during a joint performance if the violin plays in response to the piano all while simultaneously the piano performs in response to the violin. In this way, they each affectively modify one another while at the same time they modify themselves, which sustains their dual improvisation. And according to Deleuze, Cézanne also describes this rhythmic interaction when he wrote about “how to compose the canvas-easel relation with the relation of wind, and how to compose the relation of the easel with the sinking sun, and how to end up in such a way that I might paint on the ground, that I might paint lying on the ground.”

This portrayal of Spinoza’s affection will now serve to interpret some difficult terminology in Deleuze’s Francis Bacon book. Deleuze writes here that in simple sensations, rhythm “appears as the vibration that flows through the body without organs, it is the vector of the sensation, it is what makes the sensation pass from one level to another.”


The vector here is like the intensity of the affective variation to change its quantitative value. We could then conceive the body without organs as the Spinozistic body composed of continually altering differential relations. Hence, Deleuze writes that the body without organs is “an intense and intensive body. It is traversed by a wave that traces levels or thresholds in the body according to the variations of its amplitude. Thus the body does not have organs, but thresholds or levels.” As the damned soul in Dante’s Inferno twists his once protected side toward the pelting rain, waves of affective variation now impact the newly exposed part directly. It then becomes the site of sensation, where the internal waves of self-affection meet the external waves of affective variation. Yet this status is temporary, because he continually twists in the rain, making instead other parts of his body the new sites of affective reception.

Deleuze continues: “When the [internal] wave encounters external forces at a particular level, a sensation appears. An organ will be determined by this encounter, but it is a provisional organ that endures only as long as the passage of the wave and the action of the force, and which will be displaced in order to be posited elsewhere.” Sensational rhythm, Deleuze explains, can be the unpredictable variance of intensity waves that continually alters our bodily composition.

Thus Deleuze’s body without organs and its waves of sensational intensity can be viewed in light of his conception of the Spinozistic body and its continuous variations of affection, with the concept of ‘rhythm’ playing a similar role in both cases.

This provides us with a more substantial explanation for one of Deleuze’s few attacks on traditional phenomenology, in this case regarding the body without organs in contrast to the phenomenological lived body.

He writes: "this rhythmic unity of the senses can be discovered only by going beyond the organism. The phenomenological hypothesis is perhaps insufficient because it merely invokes the lived body. But the lived body is still a paltry thing in. We can seek the unity of rhythm only at the point where rhythm itself plunges into chaos, into the night, at the point where the differences of level are perpetually and violently mixed. Beyond the organism, but also at the limit of the lived body, there lies […] the body without organs."


Thus, Deleuze breaks from traditional phenomenology’s manner of conceiving the composition of the body as being made of harmoniously integrated parts that work organically with each other and with the world around them during phenomenal experiences. Nothing in its environment would stand out and appear to such a body that is completely accustomed to all the affective influences around it. Rather, for phenomena to appear to us, our bodies would need to sense things that stand out; we would need to detect differences.

A Deleuze-inspired phenomenology would explain bodily-given phenomena that appear to our affective awareness as being based on differential relations within us, throughout the phenomenal world around us, and between our bodies and the world.


Image credits:

Blue and red particles in motion
http://en.wikipedia.org/wiki/File:Translational_motion.gif
Thanks A.Greg

Blue molecule in motion
http://faculty.bracu.ac.bd/~mlrahman/Research.html
Thanks M.L. Rahman

Heart cell
http://scinewsblog.blogspot.com/2011/04/scientists-turn-blood-cells-into.html
Thanks Bluegrass Pundit

Heart beating
http://sbsmed.net/
Thanks Sterile Barrier Solutions

Circulatory system animated gif
http://www.quietmoment.org/my_weblog/2011/03/mysteries-of-the-human-body.html
Thanks John U.

Egypt protestors on a bridge
http://www.youtube.com/watch?v=rXbRdumboZ0
Thanks Freemanfilmsuk

Amazon river
http://www.youtube.com/watch?v=dn53PtW0AnA
Thanks BestofAttenborough

Earth
http://www.youtube.com/watch?v=hALtHnu4WEo
Thanks UweTube

Solar system
http://animated-sun.weebly.com/animated-solar-system.html
Thanks animated-sun.weebly

Spiral Galaxy
http://www.youtube.com/watch?v=AD9OV1Zrs4I
Thanks Kanal von beltoforion1

Galaxies
http://www.youtube.com/watch?v=X5zVlEywGZg
Thanks BrainMind.com

Spinoza. Opera, vol. 2. Edited by Carl Gebhardt. Heidelberg: Winter, 1972.
http://archive.org/details/operaquotquotre00landgoog

Geometrical Derivative animation:
http://faculty.uncfsu.edu/msiddiqu/Maple_Animations.htm
http://faculty.uncfsu.edu/msiddiqu/images/images/Gif_Folder/Definition%20of%20Derivative18.gif
Thanks Dr. Siddique of Fayetteville State University