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jected, That Des Cartes had made extension, which chAP.
II. was an accident, to be a substance, Mons. Regis an- swers, That he confounded extension which was of the Census essence of body, with the extension which belonged to n. 1. ,
Regis Réquantity; whereof the one is considered in itself, and ponse à la
Censure, the other with respect to magnitude. But let it be ch. 5. art. i. considered how he pleases, it is still but a mode belong-P. 25 ing to a substance, and not the substance itself. However, he refers us to his book of Physics for the clearing of this matter. And there we find, indeed, that he distinguishes three sorts of bodies; physical, mechanical, and mathematical. A physical body is one composed La Physiq.
Regis, tom. of many insensible parts in its due order and figure ; i. p. 273. from whence result the physical properties. A mechanical body is one composed of gross and sensible parts; which by their figure and situation are proper for particular motions. A mathematical body is å body considered with its proper extension under a regular figure, as a cube or a cylinder. But this doth not shew that Des Cartes did not confound a mathematical and physical body : for it is an easy thing to find out distinctions to avoid a difficulty ; but then they ought to be agreeable to the general sense of those terms. But here a mathematical body is confined to regular figures; whereas the general notion of it is such a body as Des Cartes himself means, when he calls it geometrical quantity, such as is the object of mathematical demonstrations, i. e. of any kind of figures abstract from physical bodies; and this, he saith, is that matter he treated of. And to such a body extension alone belongs, and to none else, either physical or mechanical.
Here then lies the difficulty as to Des Cartes's principles : he considers matter geometrically, i. e. abstractedly, with respect to bare extension, and yet sup
part. ii. n. 16.
BOOK poses the effects of physical bodies; such as division of
parts of matter one from another, and a motion of those parts in order to the composition of things. But mathematical extension is capable of no division but in the mind; for no man imagines the earth really divided by the parallels and meridians, &c. and the division of the parts of an empty space is nothing but a mathematical division, which implies nothing really in that space, but a mere act of the mind in conceiving the dis
tance between the several parts of it. Cart. Prio. But Des Cartes proves it impossible there should be
a vacuum in nature, because the extension of space and body are all one. But may not God annihilate
that air which is between the sides of a vessel; and N. 18. would there not be a vacuum between? No; he saith
it is impossible to conceive such a cavity without extension, or such an extension without matter; and if the middle substance were annihilated, the sides must come together, because there would be nothing between. By which we see, that this notion of the identity of extension and corporeal substance had sunk so deep into his mind, that he makes annihilation of the substance of matter impossible to Divine power; for there can be no such vacuity, but there must remain extension, and consequently a corporeal substance. This hath been objected to the followers of Des Cartes, and lately by Du Hamel, in his censure of Regis's Cartesian philoso
phy; and it is worth the while to see what answer he Répous.aux makes to it. He saith, That his objection about the Reflex. de M. Du Ha-annihilation of the air between the heaven and earth, ch. 4.
• . can be of no force to prove a vacuum ; because if there
be no space, they must touch one another; and if they do not, there must be space, and consequently a corporeal substance. But, saith Du Hamel, may not God, by the same power by which he preserves the bodies
between heaven and earth, destroy them, and then there chaP. must be a vacuum ? He answers plainly, That an an- _ nihilation of the substance of matter is impossible, even to the power of God, because his will is immutable. He grants that God may destroy the air, and all other bodies, as to their form or present modification; but he cannot destroy their matter, i. e. their extension, which is a true substance, and substances are indefectible. Where we plainly see that the Cartesians assert the necessary existence of matter, and that it is not in the power of God to destroy it; and whatever they may talk of the will of God, they deny any power to exercise it with respect to matter.
But Du Hamel proceeds. How can those bodies touch one another, when God can create another body between ? No, saith Regis, that still supposes a space between; and if there be a space, there must be a body; and so a vacuum is a repugnancy in itself. But this space, saith Du Hamel, is nothing but imaginary, a fiction of the mind; and there is no arguing from thence to the nature of things. Regis replies, That their ideas depend on the objective realities of things; and that the idea of space or extension is one of their primitive ideas; and that it represents substance, and all substance is incorruptible. Still we see the necessary existence of matter is looked on by them as a fundamental principle, and depending on primitive ideas.
Mons. Bernier puts the case of air being annihilated abrégé, between two walls; and he desires to know of the Car-. tesians, whether these two walls will come together or not? They say, They must, if there be nothing between True, saith he, there is nothing corporeal, or that touches our senses, no substance or accidents ; but there is a true distance remaining. Suppose a chamber twenty feet long, fifteen feet broad, and ten feet high ;
BOOK and these dimensions to be measured, and one wall
twenty feet distant from the other : it cannot be said that it is the air that makes the distance between them; how then comes this distance to be quite lost, if the air be destroyed ? They have no answer, he saith, but to say, it is an impossible supposition; and they will rather deny God's omnipotency in annihilating the air, than let go their opinion. Mons. Regis, in his Physics,
takes notice of Bernier's doubts; and, in answer to Reg. Phys. them, he resolves it at last into this: That it is impos3. n. 3. sible there should be an annihilation, so as to make a
vacuum, because substances cannot cease; not from the nature of things, but from the immutable will of God. And, after all possible objections, here they stick, and seem resolved to maintain, that extension and matter
are the same. Rohault, Even Mons. Rohault himself, although in some Tr. Phys. 1. i. c. 7. things he saw it necessary to leave Des Cartes, yet in
this he persists, That the essence of matter consists in extension, and that space and matter are the same ; and therefore a vacuum is impossible. And to the
objection about the walls of a chamber standing, when C. 8. 1, 2, the air is annihilated, he avoids answering as to God's
omnipotency; but, he saith, according to our understanding the walls must come together. And to that about the walls' distance not depending on the air, he answers, That the being of the walls does not depend upon the air within, but the state or disposition of them doth upon the extension between them; which he supposes impossible to be taken away, and that the substance of matter hath a necessary existence.
The substance of this argument comes to this. Des Cartes makes all the matter of the world to be one and the same; but he asserts the essence of matter to be extension, and that extension can neither be created
nor annihilated ; and therefore it is impossible, upon Chap. his principles, to make out the dependence of matter _“. upon an infinite Creator. If it be said, that Des Cartes expressly saith, That it seemed manifest to him that Cart. Prin. there is no other general cause which created matters with motion and rest but God; and that in the fragment of his last answer to Dr. H. M. he saith, That Id. Epist. if matter were left to itself, it would not move, Ep. 93. but that it was first moved by God; I answer, That according to his principles the substance of matter must be before, because there must be space; and space and matter are the same. And I can see no possible way of clearing him, but by saying, that he held two sorts of matter : one part is physical matter, which God gave motion to at first when he created it, and out of which the world was framed ; and the other mathematical, which consists in mere extension : but how to reconcile these two to his asserting one and the same matter in the world, is a thing above my understanding.
The next thing to be considered is, Des Cartes's un- II. dertaking to give an account of the phenomena of the universe from the mechanical laws of motion, without a particular Providence. We are told by some, who have been very conversant with the atheistical persons of our age, That they despise the Epicurean hypo- Fr. Cuperi thesis, of the world's being made by a fortuitous con- Atheism. course of atoms, as a ridiculous thing; and think\. ii. Moses's account more probable than that, (which is a great favour indeed.) So that it is to little purpose now to spend time in shewing how precarious and unsatisfactory the principles of Epicurus were, who supposed motion in matter without the least ground for it; but Des Cartes was a man of too great sense and judgment to commit such blunders as Epicurus was guilty of (whom one of his sharpest adversaries allows to have Phil. Cart.
c. 8. n. 4.