As I have already described it, Descartes’ Atomism reduced all material to infinitely divisible mathematical extension — length, breadth, thickness — a universal homogeneity.

That he would explain physical reality as mere homogeneous mass and communicated local motion which was capable of being transmitted and transformed in infinitely different modes.

This system is the philosophic interpretation of what is in effect basic chemical atomism. Its leading tenets may be expressed in the following propositions:

The Atoms of simple bodies are homogeneous, i.e. of the same nature. They are distinguished only by a quantitative difference of mass and motion.

All corporeal properties are reducible to modes of local motion.

The substantial being of the atom is itself inert, possessing no inherent principle of activity. Communicated local motion constitutes the whole of its energy, which is therefore merely borrowed.

Intrinsic finality of the substantial adaptation of beings to determined ends is for modern cosmology a useless fiction. The working of natural forces and the harmonious succession of material phenomena is adequately explained by mechanical laws.

This Philosophic aspect of Mechanism has been rigorously examined and to a great extent Descartes reliance upon it for explanatory principles is thereby undermined.

To set these out in greater detail, the arguments run thus:

Mechanism attributes to motion three fundamental properties:-

1. Motion is the principle of all material activity; it is to be held to account for the birth of all new phenomena that occur in the universe.
2. It has the aptitude of transforming itself into numerous modes, such as heat, magnetism, electricity, light and weight.
3. It passes unchanged from one body to another, in a word it is transmissible..

Before undertaking to examine these propositions, we should be sure that we have a clear notion of what "motion" (or movement) means.

Aristotle suggested; "Movement is the actuality of a being which is formally potential" i.e. is capable of having some further reality.

Movement is an actualisation, a determination which it is necessary to distinguish from the simple power to act or to receive perfection in being.

A stone when lying still is susceptible of movement, but it is not yet in movement.

Movement begins when that susceptibility, or potentiality begins to be actualised.

It is therefore the actuality of a being still potential to possess further reality, to be something else.

Yet this actuality which gives bodies a new position and constitutes all the mobile reality of movement cannot be anything terminated or complete in all respects.

If you consider the stone which you have thrown into space, at the precise moment when it receives its new place, you can say that it has been moved, but it is no longer in movement. If then you wish to conceive it in the state of movement, you must consider it as on its way towards a new position, which is no longer its starting point nor yet its final resting place.

In other words, although determined by a new position, the moving object would appear in movement only on the condition of its being in proximate passive potentiality with regard to further actualisation.

The actuality constitutive of movement is thus seen to a be an incomplete reality bearing a two-fold relation — on the one hand to a receiving or moveable subject which it determines by placing in a new position in space, and on the other to an ulterior perfection or a new position which the moving body continuously receives.

First principle of Mechanism;

Local movement is a force and a cause capable of producing a mechanical effect.

Criticism

According to the definition given above, movement comprises three elements indissolubly united.

1. First there is a movable thing in passive potentiality
2. An actuality or determination which realises the passive potentiality of the subject by giving it a new location.
3. And the tendency of the subject to receive hic et nunc other spatial determinations.

Now in these elements, whether considered individually or together, there does not appear the least indication of any power of action.

1. In virtue of its aptitude to pass from the state of rest to that of movement, the subject of movement manifestly cannot communicate anything or produce anything; it is capable only of receiving something under the influence of an external cause. Passivity, which excludes all dynamic power, is the essential characteristic of this first element which constitutes movement.
2. Whatever reality exists in movement consists in the continuous determination by which the body is fixed at each moment in different positions in space. Now this actualisation has only this one effect, of giving to the body which receives it positions so fleeting that one disappears as another becomes real.
3. The tendency possessed by the moving body constantly to receive further actualisation's is clearly a passive tendency and accordingly one incapable of producing an effect of any kind.

Local movement, therefore, considered in its separate elements and in its whole reality, is powerless to exercise any causal influence whatsoever.

First objection

Is not every body in movement endowed with a dynamic power proportionate to the intensity of the movement by which it is animated?

Must we not then conclude that movement is the source of this energy?

A body in movement can certainly produce mechanical effects. Yet, the real cause of these effects is not the local motion, but a force properly so called, a motor-quality inherent in the mover.

In the first place, the study of movement proves that this accident is incapable of exercising efficient causality.

Secondly, experience confirms this deduction. A billiard ball which is at rest on the table may be put into motion by a sharp stroke of the cue. As long as the cue is in contact with the ball you can attribute the movement to the exercise of a force that is within the man who pushed the cue.

But once the contact has ceased and the player's action has ended, the cause of the movement which continues (and indeed would never cease but for exterior resistances) must lie elsewhere.

In fact, either the new positions of the ball are not real, and in this case it is foolish to attribute a dynamic power to this movement; or these new positions are real, and thus demand a permanent stable cause which is present during its effects and consequently resides in the moving subject itself.

For its is no longer the player who is producing the fleeting and constantly renewed series of the movement, for he has ceased altogether to influence the ball.

Whence comes this energy? It was communicated to the ball at the moment of shock; it is the immediate effect of the player's action, and the movement is only the result and partial measure of it. Like all other qualities, this force is by its nature stable and permanent, and cannot be destroyed except by a contrary force.

Second Objection

Does not movement, when it has once been started, carry along in itself the principle of its continuity,, in the sense that every spatial position is itself the cause of the position which immediately follows it?

This hypothesis is overthrown by the Mechanists themselves. For to say that each position occupied by a body gives it the power of procuring the next is to affirm that matter at rest can by its own initiative communicate movement to itself, and thus defy the law of inertia.

The successive positions through which the body in motion passes in its action are not of a different nature from the last position where it comes to rest.

There is no real difference between them

If the first ones form part of the movement, it is solely because each supplies a stage in the process.

Movement is transmissible from one body to another

Criticism;

Like all other accidental realities, movement is made concrete and individual by the subject in which it inheres; it is dependent on it intrinsically and must remain attached to it, otherwise it would disappear from the world of reality.

The hypothesis that movement is transmissible is moreover condemned by experience. If two bodies meet, the one being in a state of motion, the other at rest, the result is that the moving body comes to rest and the stationary one is set in motion.

Now where does this new motion come from? Has it been transmitted from the body in the motion? Evidently not.

At the moment of contact, the moving body could not transmit the positions through which it had passed, since they no longer existed; nor again its present position, or else it would no longer have a place in space; nor again the future positions it could have received, since they still exist only in the domain of pure possibilities.

No particle of the movement of the moving body has then been transmitted to the body put in motion.

And as the new movement demands a cause, recourse must be had to the motor forces brought into play by the contact.

All the forces of nature are said to be modes of movement that are capable of being transformed into one another.

Criticism

For one thing to be transformed into another, it is necessary

1. That it be deprived of some modes of being that characterize its present state, and
2. That part of the original thing remain in the final stage of the transformation.

In default of the first condition, if the thing remains identically as it was, it will undergo no transformation; in default of the second, there would be an annihilation and a subsequent creation.

Now in any case a new movement does not contain a part of the movement which preceded it.

For, the transitory actualisation's which constitute the whole reality of movement are susceptible of two changes — changes of velocity and changes of direction.

Let us consider each of these:-

Change of velocity.

1. On receiving an impulse, a body already moving with a velocity of two metres a second acquires a speed twice as great. Now the only connection there is between these two movements is that one succeeds the other.

To the series of positions occupied by the body in motion and now no more, at the moment of impulsion there succeeds a new series of transitory localisation's.

It is impossible to see in this second phase of the phenomenon the least trace of the former phase.

Change of direction:

2. If a body in motion receives a lateral shock, it changes direction. Now in this new direction, be the motion rotary, vibratory or undulatory, one cannot discover any trace of the movement which preceded it, since at the moment of shock all the previous spatial determinations had completely disappeared one after the other

Hence movement is never the subject of any transformation.

It is true that the succession of the phenomena which we have just analysed awakens the idea of change, or rather of a certain transformation. But where mechanism errs is to place it in movement rather than in its real cause.

In the cases cited the motor force of the bodies, and that alone, has undergone the modifications or alterations which have produced the changes of velocity and of direction.

General reasons for the repudiation of Mechanism

FIRSTLY: Mechanism has exaggerated the part played by movement and has falsified the notion by making it the Principle of all the changes that take place in the universe.

Hence arise contradictions when it is considered metaphysically, as well as its incapability to account for that vast array of facts where it is evident movement cannot take its origin from movement.

SECONDLY: The second cause is its rejection of the teleological point of view in the explanation of scientific facts. The invariable recurrence of the same chemical and physical phenomena, the indissoluble union of fixed properties with fixed substances, in a word the cosmic order, demand a permanent and stable cause, an immanent directive power or principle of finality proper to each body and really specific.

But such a principle Mechanism rejects by substituting for it its dogma of the homogeneity of matter.

THIRDLY: A third cause is its reduction of all the forces of nature to different modes of local movement. Although all corporeal activities are accompanied by movement and on this account make the formation of mathematical physics possible, it is undeniable that they also present a qualitative and differential aspect which cannot be discovered in the modes of local movement, and this aspect mechanism fails to consider, thereby dooming itself to give but an incomplete explanation of the physical properties of matter.

Furthermore the doctrine of the transmissibility and the convertibility of movement into light, heat, electricity and magnetism is the necessary consequence of the theory which reduces all to motion.

Does this comprise a complete refutation of Descartes himself? I think not; for, of course, Descartes is more than the sum of what exists in his methode and, just as it would be unfair to attempt to refute his whole philosophy by insisting that it logically hangs upon the untenable syllogism built on his Principle VII, "I think, therefore I am .." it would be less than honest not to seek out and examine the causalities underlying his Metaphysics and his Cosmology.

In this study, therefore, I also attempt, insofar as it touches upon causalities whether directly or by effects or consequences, to trace the ancient but unbroken provenance of Descartes’ metaphysics, his philosophy of physics and his natural philosophy; and to examine its place in fixing explanatory principles in the light of the intellectual climate of his time and (whenever necessary) from the standpoint of those who followed him, and from our own perspectives today.

Can Descartes suceed in any respect with this universal explanation for phenomena generally through his new method.

By present day standards this seems an impossibly tall order for any Cosmology. Indeed few would quarrel with the usual caveat against seeking for a logical connection between a hypothesis and some cosmological system, certainly as though the one must be the consequence of the other.

"There is no doubt that several of the geniuses to whom we owe modern physics have built their theories in the hope of giving an explanation of natural phenomena, and that some have even believed they had supplied this explanation.

"But that, nevertheless, is no conclusive argument against the (contrary) opinion. Chimerical hopes may have incited admirable discoveries without these discoveries embodying the chimeras which gave birth to them." — Pierre Duhem The Aim and Structure of Physical Theory.

Where did it come from, this philosophy of nature. Or what is corporeal substance that it can also change as in a chemical reaction?

The mechanists whether materialists (as to the human soul or not) like Democritus, Epicurus, Lucretius of old or Hobbes 17^th c. or spiritualists like Descartes — had simply reduced corporeal substance to matter, which they then, it seems, confused with quantity or geometrical extension.

They could, therefore, admit no essential or specific difference among bodies, which for them, as for Descartes, are all modifications of one substance. Also the physical universe is devoid of quality and energy, since space and local motion alone are real and the union of matter and spirit in a being such as man becomes absolutely unintelligible.

Dynamism on the other hand tended to the contrary to get rid of matter as a constituent of bodies. It culminated in the system of Leibniz, who reduced corporeal substance to units of a spiritual character, Monads analogous to souls. For Leibniz extension, indeed sensible reality as a whole, is nothing more than an appearance or a symbol, and the corporeal world is absorbed in the spiritual. From this came Boscovich's 18^th century "points of force" concept of corporeal substance which claimed to explain everything in the physical universe as a manifestation of one sole reality, energy (but fails to give a philosophical explanation for this or definition)

So the time seems to have passed when an intuitively arrived at explanatory theory (within specific frames of reference) would be accepted so uncritically — but has it?. So fecund is this age with scientific discoveries that science itself is perceived as its own cosmology, tending with a seeming naturalness towards universal equivalence. That perception however is confronted with a psychological reality, and Positivism which had to adjust itself to blatant contradictions in its political "persona" fails again before the seeming infiniteness of detail gathered by modern sciences.

Philosophy’s first justification is "to grasp the entire universe in a small number of principles — to enrich the intellect without burdening it, as Jacques Maritain so succinctly argued its cause.

Even beyond the merely empirical, who can be blind to the astronomically profuse practical and theoretical consequences that have arisen from the hard facts which the special sciences (whose elemental philosophies are the product of logical and necessary processes and always autonomous) have produced. The nature of the beast, for all that, is to find a habitat, which I argue is its need for classification and explanation — whatever Positivist dogma might attempt to suppress this instinct.

Does this also help towards explaining the paradox wherein the mechanism embraced by Descartes first empowered and then betrayed him; but in the end cannot seem to exist without him — as though, all else having failed in the realms of experiment, and empirical classification, the human mind failed ultimately as well and cannot escape its need to understand; and to that end will strive even against reason to seek out explanations — to the length of calling up whichever ghost is least likely to spook its cherished sentiments. This is despite quite deliberate efforts to lay the ghost of Descartes. (ref. Tom Sorell Descartes, p110)

But the ghost busters include those from an ever widening stream in modern philosophy which has as its paradoxical object the actual denial of this instinct to know, and these are unfriendly to any postulation which proposes a connection between reality and an objective apprehension of that reality. It is worth noting that such idealistic or transcendental schools rarely offer any real threat to Descartes position; neither is it threatened by the antithetical philosophies of logical positivism and materialism.

But is it not tragic that while Leonardo da Vinci, Galileo, and Newton are secure in the Science Parnasus, Descartes, for all his diamond hard gifts, is languishing in a soft solipsist Limbo? A place neither universal enough to be called philosophy, nor hard enough to be admitted into the activities of our real world.

Section two

Research into Descartes' Cosmology alone seems to indicate that he has greatly influenced natural philosophy, and even numerous hypotheses and theories, right up until the present day — both positively and negatively.

Much of what is worst is not Descartes' fault. Those to blame are largely ideologues — misusing his ideas not least by confining distinct intellectual procedures to proofs unsuitable to them in order to adapt every and any dynamic to the belief systems which accommodate a Mechanistic/Materialistic world-view. True or untrue as that world view may be, it is surely unscientific to distort and so conform a great thinker's ideas to that end — more especially if his own world-view represents its very antithesis.

For example, Mechanism, if not exclusively Cartesian mechanism, because of its exclusion of any dynamics other than local motion, as well as its principle of material homogeneity as the necessary result of extensional essence, can be made to support the general notion that the material universe self-originated and acts randomly — if, that is, the universe is not considered to exist in a state of eternal stasis — and that its activity is undirected or uncontrolled other than intrinsically, and that the question of end or purpose has no meaning.

Descartes, rightly or wrongly, nevertheless vehemently disagreed with such a conclusion and would be less than pleased that it should arise from his own Cosmology if we are to believe his own protestations of Faith in a Divine Creator.

But even at the level of Natural Philosophy, the immediate application of that philosophy to practical theory causes "cracks" to appear.

Descartes himself provided (unwittingly) the most elegant evidence against himself — in this case supplying proof of a glaring incongruity when experiment and theory were asked to depend upon his overall philosophy.

He proposed a theory to represent the phenomena of simple refraction; the principle object of his brilliant treatises, Dioptrique and Météores, to which Le Discours de la Méthode provides a perfect preface.

The theory is based on the constant relation between the sine of the angle of incidence and the sine of the angle of refraction, his theory arranges the properties of lenses of different shapes and of the optical instruments made up by these lenses. It considers the sensible phenomena of vision, and analyses the law of the rainbow.

Descartes also offered an explanation of light effects — that light is but an appearance; the reality being a pressure engendered by the rapid motions of incandescent bodies within a "subtle matter" penetrating all bodies. This subtle matter is incomprehensible, so that the pressure which constitutes light is transmitted to it instantaneously to any distance. Therefore it would follow that no matter how far away a point is from a light source, at the very instant the latter is lit, the point is lit.

This instantaneous transmission of light is an absolutely necessary consequence of Descartes' system of physical explanations.

A contemporary, Beeckman, denied this proposition and tried to refute it experimentally.

He was ridiculed by Descartes, thus: "To my mind, it (the instantaneous velocity of light) is so certain that if, by some impossibility, it were found guilty of being erroneous, I should be ready to acknowledge to you immediately that I know nothing of philosophy.

"You have such great confidence in your experiment that you declare yourself ready to hold all of your philosophy false if no lapse of time should separate the instant when one sees the motion of the lantern in the mirror from the instant one perceives it in his hand; I, on the other hand, declare to you that if this lapse of time could be observed, then my whole philosophy would be completely upset." (R. Descartes, Correspondence, Ed P. Tannery and C. Adams, Vol. I, Letters LVII, p.307.)

Whether Descartes himself created the fundamental law of refraction or borrowed it from Sneer, as Huygens hinted, is still a heated question. What is certain is that this law and the representative theory based on it are not offspring of the explanation of light phenomena Descartes proposed.

The Cartesian cosmology had no part in generating them; nothing produced them except experiment, induction, and generalisation.

His most exacting, but scrupulously fair, modern critic, Pierre Duhem, admitted: "Moreover, Descartes never made the attempt to connect the law of refraction with his explanatory theory of light, although at the beginning of the Dioptrique he developed mechanical analogies concerning this law. He compared the change of direction of the ray which passes from air into water to the change of the path of a ball thrown vigorously and passing from a certain medium into another more resistant one.

"But such logically reckless mechanical comparisons mistake the theory of refraction with the law of emission — where a ray of light is compared to a stream of particles projected violently from the light source."

Again, this explanation, maintained in Descartes' own lifetime by Gassendi and later taken up by Newton, has no analogy with the Cartesian theory of light; it is incompatible with that theory.

Thus, the Cartesian explanation of light phenomena and the Cartesian representation of the diverse laws of refraction are simply juxtaposed without any connection or penetration.

In due course, the Danish astronomer Romer proved that light is propagated in space with a finite and measured velocity, and the Cartesian explanation of light phenomena collapsed completely; "but it did not bring down with it, even the slightest part of that doctrine which represents and classifies the laws of refraction. This continues even today to form the major part of our elementary optics."

Descartes has here obviously survived Cartesianism in this initial crisis, but that he did survive speaks more for his physics than his metaphysics. Indeed it might be argued that had his practical genius not been so powerful it might never have outlived his philosophy. Other geniuses left crucial discoveries but their names are now forgotten because they stood for other things that failed or failed to find a thermal trend upon which their work would rise ; names like Simon Stevin, (1548 – 1620) or Professor of the College of France, Giles Roberval (1602-1675), or even the Pierre Hèrigone whose study of the siphon so dramatically improved the science of statics for Descartes himself to advance.