The World as Will and Idea, Vol. II — Arthur Schopenhauer, trans. Haldane & Kemp

It is very desirable that the matter should be further investigated, and as this woidd demand tiresome and extensive researches, some German Academy might very well make the question the subject of a prize essay. Now in the same relation as that in which Kant here stands to Priestley, and perhaps also to Kaspar "Wolff, and Maupertuis or his predecessor, Laplace stands to Kant.

For the principal and fundamental thought of Laplace's admirable and certainly correct theory of the origin of the planetary system, which is set forth in his "Exposition du Systeme du Monde" liv. v. c. 2, was expressed by Kant nearly fifty years before, in 1755, in his " Naturgeschichte und Theorie des Himmels," and more fully in 1763 in his " Einzig moglichen Beweisgrund des Daseyns Gottes," ch. 7.

Moreover, in the later work he gives us to understand that Lambert in his " Kosmologischeti Brief en," 1761, tacitly adopted that doctrine from him, and these letters at the same time also appeared in French (Lettres Cosmologiques tur la Constitution de VUnivers). We are therefore obliged to assume that Laplace knew that Kantian doctrine.

Certainly he expounds the matter more thoroughly, strikingly, and fully, and at the same time more simply than Kant, as is natural from his more profound astronomical knowledge ; yet in the main it is to be found clearly expressed in Kant, and on account of the importance of the matter, would alone have been sufficient to make his name immortal.

It cannot but disturb us very much if we find minds of the first order under suspicion of dishonesty, which would be a scandal to those of the lowest order. For we feel that theft is even more inexcusable in a rich man than in a poor one.

We dare not, however, be silent ; for here we are posterity, and must be just, as we hope that posterity will some day be just to us. Therefore, as a third example, I will add to these cases, that the fundamental thoughts of the "Metamorphosis of Plants," by Goethe, were already expressed by Kaspar Wolff in 1764 in his "Theory of Generation," p. 148, 229, 243, &c. Indeed, is it otherwise with the system of gravitation f the discovery of which is on the Continent of Europe always ascribed to Newton, while in England the learned at least know very well that it belongs to Robert Hooke, who in she year 1666, in a "Communication to the Royal Society, " expounds it mite distinctly, although only as an hypothesis and without proof. The VOL. II, P 226 FIRST BOOK. CHAPTER IV.

principal passage of this communication is quoted in Dugald Stewart's " Philosophy of the Human Mind," and is probably taken from Robert Hooke's Posthumous Works. The history of the matter, and how Newton got into difficulty by it, is also to be found in the " Biographic Universelle," article Newton. Hooke's priority is treated as an established fact in a short history of astronomy, Quarterly Review, August 1828. Further details on this subject are to be found in my " Parerga," voL ii., § 86 (second edition, § 88). The story of the fall of an apple is a fable as groundless as it is popular, and is quite without authority.

(2) To No. 18 of Matter.

The quantity of a motion (quantitas motus, already in Descartes) is the product of the mass into the velocity.

This law is the basis not only of the doctrine of impact in mechanics, bat also of that of equilibrium in statics. From the force of impact which two bodies with the same velocity exert the relation of their masses to each other may be determined. Thus of two hammers striking with the same velocity, the one which has the greater mass will drive the nail deeper into the wall or the post deeper into the earth.

For example, a hammer weighing six pounds with a velocity = 6 effects as much as a hammer weighing three pounds with a velocity = 12, for in both cases the quantity of motion or the momentum = 36. Of two balls rolling at the same pace, the one which has the greater mass will impel a third ball at rest to a greater distance than the ball of less mass can.

For the mass of the first multiplied by the same velocity gives a greater quantity of motion, or a greater momentum. The cannon carries further than the gun, because an equal velocity communicated to a much greater mass gives a much greater quantity 0) motion, which resists longer the retarding effect of gravity.

For the same reason, the same arm will throw a lead bullet further than a stone one of equal magnitude, or a large stone further than quite a small one. And therefore also a case-shot does not carry so far as a ball-shot.