ing for the nature of human life, we should be thought to assign a very mean reason, were it to be urged, that a man lives to-day only because he lived yesterday for there are certain physical principles on which animal life is preserved, and without which it, cannot possibly subsist. It is true, the principles of animal life are not very simple, nor in all respects investigable; yet reason assures us, that life must cease, and that instantly, when these are no longer present.

We must argue in the same manner about motion; that a body continues to move, only so long as the natural causes of motion continue to act upon it; and that rest, which is mechanical death, must inevitably follow when the causes of motion are no longer present to it. There may be subtile cases, in which it is as hard to trace the cause of motion, as to shew why life remains for some time in an animal body under water without respiration; but still the general assertion must be true, that every effect must have its cause, and that if the effect is permanent, the cause must be so too. If life were preserved in any human body without air in the lungs, or any remaining vital warmth at the heart to keep up the fluidity of the blood,

this would be an absolute miracle, not to be accounted for by any principles of mechanism, nor resolvable into the doctrine of physical causes. And it would be as great a miracle if an inanimate body were to move permanently without any permanent cause; or what is worse, it would rather seem to exclude the possibility of miracles: and I cannot but wonder it was never duly considered by modern philosophers, that neither the power nor the providence of God are necessary to that body, which moves to-day only because it moved yesterday. This principle leads naturally to Atheism, and, with very little difference, is the principle on which the Greek Atheists built their system; they gave to atoms an oblique motion without any permanent cause; which, together with innate weight, essential to their constitution, carried them through the whole course of their performances in the natural world*.

True philosophy will instruct us better; that God is the source of motion, as strictly as of life; that all things move in him, as all intelligent

* Epicurus ait atomum, cum pondere et gravitate directa deorsus feratur, paululum declinare. Cic. de Nat. Deor. lib. i. 25.

intelligent beings live in him; that therefore, neither life nor motion can remain for one moment, but so long as they depend either on his own immediate power, or on such means as that power hath established in subordination to itself. Where we can observe and understand these means or intermediate causes, it is not necessary to recur at every step to the primary cause: and as it is the constant and ordinary method of Divine Power to work with natural means, reason will require us to understand them, whether we can observe them or not. The body, which we now project with ease to a great distance, would be removed no farther than the hand carries it, unless there were some power always in action, and ready to continue its motion; till, by the intervention of other natural obstacles, it is brought to a state of rest. We cannot be at a loss for a power adequate to such an effect, when we consider that the agent which occasions gravity and cohesion is always present.

Difficult Case of a Pendulous Body considered. Let us examine this matter more particularly. We suspend a body by a line or rod,

and

and call it a pendulum; and every person knows what motion it is capable of. A body thus suspended describes an arch; in one half of which it descends,, and ascends in the other. We all allow that it descends to the lowest point of the arch by the power of gravity; but we cannot agree so well what happens when it gets beyond that point. Does it fall by the cause of gravity; and rise again by no cause at all? If you say it rises by the motion it has acquired in falling, I ask, what is this motion? It is nothing but an effect; and to say that it moves by motion, is to say nothing at all: for motion is not a thing by itself, as philosophers seem very falsely to have considered it; it is not a quality which a body can get possession of, and run away with; it is a mere effect, and, as such, must be referred to some cause, or given up as unintelligible. But to return to our pendulum: you will say it cannot rise. by the power of gravity, because that is inconsistent with the direction of gravity. However, notwithstanding this apparent difficulty, I am persuaded that the same power which naturally carries a body downwards, will carry it any way according to the circumstances of the case: for is not the whole

VOL. IX.

I

arch

arch of a pendulum described out of the line of gravity, except the first and last points of it? In falling to the lowest point of the arch, it moves for a little time very nearly in the tangent of its curve, at right angles, to the line of gravity; or, in other words, its gravity gives it motion in a horizontal direction: and if thus much, why not all the rest? Why must it leave the body at one point of the tangent line, and not continue to act upon it in the same line? If we can keep the cause and the effect together ever so little on the other side the perpendicular, the difficulty is over: then the body performs the whole course of its vibrations by one and the same cause; and the reciprocations we observe in the moving body are first in a medium, whose vibrations are continued with infinite freedom. This is more satisfactory than that other sort of reasoning, which assigns a cause for one half of the motion, and a law (which cannot execute itself) to account for the other half; and that there is a certain mathematical point at which they are miraculously changed one for the other. If the difficulty of making a body rise by gravity should shock us, let us word. the matter right, and say it rises by the cause of gravity:

or