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all occasions to run to miracles and Divine power. CHAP. Who puts them upon it? We may certainly allow an
Rohault, ordinary course of Providence, as to causes and effects, part. i... without asserting these notions of Des Cartes; but this 10. n. 13. is a pleasant way of taking it for granted that none but his principles are fit for philosophers.
Come we now to examine his catholic laws of motion: II. and of all things those ought to be very clear and certain, because so much depends upon them; and yet I am afraid we shall hardly find one of them to be so.
The first of them is, That every thing remains in the same state it was in, unless it be changed by external causes. From whence he concludes, That which Cart. Prinis moved always continues to be moved ; and that no-n. 37 thing tends to rest which is contrary to the laws of nature, because rest is contrary to motion : and nothing tends to its contrary, for that would be to tend to its own destruction. The main thing intended by this, is to assert the continuance of motion in the parts of the universe, upon their being once put into it; so that rest is a state of violence to a body once moved, because rest and motion are contrary to each other. But this is a very weak foundation to build so much upon : for we are not to consider rest and motion abstractly, but physically, together with the bodies in which they are: and I think it will be very hard to persuade any body endued with sense and motion, that, after wearisome motion, he doth aim at his own destruction by seeking for rest. This is a sort of reasoning would not be expected from philosophers; that because motion and rest are contrary motions, therefore no body in motion can tend to rest. But every thing continues in the state it was in, till it be put out of it; therefore every thing in motion must continue to move. This is not clearly expressed : for if it be meant, that every thing STILLINGFLEET, VOL. II.
BUOK from itself continues in its original state, then it is not
true. For matter, he confesses, would rest, if God did not give motion to it; and so it must continue to rest, and there could be no motion at all. If it be meant that every thing continues in the state God put it into, unless he appointed several causes to alter it, then it is true; but it doth not serve his purpose. For if God hath appointed both motion and rest for some bodies, it can never be said that such tend to their own destruction, when they tend to that rest which God and nature appointed for them. If God hath appointed them for continual motion, as the great bodies of the universe, then they must continue in it; not by virtue of any inherent law of motion, but by the immutable will of God. Des Cartes saw it necessary for God to put matter into motion, but he would have the framing of the laws of this motion himself; whereas he had acted more respectfully towards his Maker, and more like a philosopher, i. e. more consonantly to his own principles, to have left God, that made the world, and gave motion to matter, to have settled those laws of motion, which were agreeable to his infinite wisdom.
For these notions are unbecoming philosophers, to make motion a mere mode of matter; and this mode to be supported by Divine concourse; but so, that motion and rest being contraries, whatever is in motion must continue in it; because motion and rest being contra
ries, nothing can tend to its own destruction. Cart. Prin- Besides, I know not how to reconcile this with cip. part. ij. n. 39 another law of nature, as he calls it, That all bodies in Part. iii. a n. 55.
a circular motion endeavour what in them lies to recede from the centre of their motion. Is not a body put into a circular motion, in a state belonging to it? How comes it then not to continue in that state, but to endeavour all it can to get out of it? And yet all the
phænomena of light depend upon this law : That the CHAP. round particles of the second element endeavour to re-cede from their centres; not from any cogitation, (no.“ doubt of it,) but because they are so placed and incited to that motion. Is that possible, and yet all bodies continue in the state they are in, when they endeavour what they can to get out of it? Are not these more contrary than motion and rest ? I do not meddle with external hinderances, but the natural endeavours of bodies. But it may be said, That Des Cartes intends his rule only of primary and simple motions, and not of circular, which are violent and unnatural. So indeed his words seem to run at first, that this rule relates to simple and undivided bodies; but then, I say, it is of no use as to the present phænomena; and he speaks of the laws of such motion as we may observe in bodies : which words signify nothing, unless his law reaches to the bodies now in being; and I see no reason for him to suppose circular motion to be any more repugnant to the nature of matter, than any other. Regis, to avoid this, saith, That circular motion is not unnatural, Réponse, but accidental; and the state of the body is to be taken ch. 1o. from what it would be if external causes were removed, i. e. in a right line. But he doth not attend to the consequences of this; for then the circular motion of the heavens must be accidental, and not under the care of Providence, or the immutable will of God. For God's will, he saith, is, that every body be preserved in its own state ; now, saith he, the state of a body in motion is in a right line, and the endeavour of nature is to keep to that. Then, say I, whatever motion is against the state wherein nature designs it, must be not only accidental but violent, because it is against the course of nature: and if it be violent, it cannot be supposed to be under God's immutable will; but if it
BOOK be not violent, then a body in circular motion must en
deavour to preserve itself in that state, and not to recede from it, as Des Cartes supposes.
Mons. Du Hamel objects against this law, that permanent beings do indeed endeavour to preserve them-. selves in the state they are in : but it doth not hold in beings that are successive; because the former are in
their full state at first, but it is otherwise in sucRéponse cessive. But, saith Regis, this doth not hinder them aux Reflex. part. ii. c. from not doing any thing to their destruction. So
that it is a plain case no body in motion can tend to rest, because motion and rest are contrary; and this is a fundamental law of nature, for this weighty reason.
The second law is, That all motion, according to nature, is in a right line, and that oblique and circular motion arises from the motion and interposition of other bodies; and whatever body is moved circularly, hath a perpetual tendency to recede from the centre of the circle it describes.
Now, if this rule had that evidence which is necessary to make it a fundamental law of motion, it must be proved either from the nature of matter and motion, or from the immutable will of God. The latter is not pretended to be proved, but only from the immutability and simplicity of the operation whereby God doth preserve motion in matter ; which only regards that very moment, without regard to what was before. But how from hence it follows that motion, which extends to more moments, should be determined one way rather than another, I cannot apprehend. For if the motion be in a right line, it must be in more moments than one, as well as in a circle; and if it prove any thing, it is that God preserves motion only in a point: but Des Cartes owns, that it cannot be conceived in an instant,
although in a right line. How then comes motion in CHAP. a right line to come from God's immutability, and not in a circle ? Because it is determined in every instant towards a right line. This ought to have been made more evident than from the instance of the sling : for the falling down of the stone to the earth is certainly from another cause, viz. from the principle of gravitation, and not from the inclination of matter to move in a right line. Neither can it be said to come from the nature of matter, or motion ; for a circular motion hath as much the nature and definition of motion, according to Des Cartes, as the other : and matter is of itself indifferent which way it moves; and some have thought circular motion more perfect, because they observed the motion of the heavens to be so. But if it arises from the impediments of other bodies, they must shew that matter was first put into motion in a straight line; and if God put all the parts of matter at first into motion in a right line, how came the impediments to make it circular? For God preserves motion as he gave it: he first gave it in right lines, and his will is immutable, therefore it must always so continue; and so circular motion will be impossible.
But let us suppose circular motion, how comes it to be so evident as to be made a law of nature, that a body in that motion always endeavours to recede from the centre? How is this consistent with the principle of gravitation and attraction, which depends upon mathematical demonstrations ? Can it be in the nature of bodies to tend to the centre, and to recede from it at the same time? And it is a very improbable thing that gravity should be nothing else, but some particles being, not so quick in their motion from the centre as others are, these being left in the lurch, and pressed by the motion of the other, do sink under them, and so come.