in 1777, and the second edition in 1782, while Kant's work was published in 1786. Unconscious recollection may certainly be assumed in the case of subsidiary thoughts, flashes of wit, comparisons, &c., but not in the case of the principal and fundamental thought. Shall we then believe that Kant silently appropriated such important thoughts of another man? and this from a book which at that time was new? Or that this book was unknown to him, and that the same thoughts sprang up in two minds within a short time? The explanation, also, which Kant gives, in the "Metaphysical First Principles of Natural Science" (first edition, p. 88; Rosenkranz's edition, p. 384), of the real difference between fluids and solids, is in substance already to be found in Kaspar Freidr. Wolff's "Theory of Generation," Berlin 1764, p. 132. But what are we to say if we find Kant's most important and brilliant doctrine, that of the ideality of space and the merely phenomenal existence of the corporeal world, already expressed by Maupertuis thirty years earlier? This will be found more fully referred to in Frauenstädt's letters on my philosophy, Letter 14. Maupertuis expresses this paradoxical doctrine so decidedly, and yet without adducing any proof of it, that one must suppose that he also took it from somewhere else. It is very desirable that the matter should be further investigated, and as this would 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 Système 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 möglichen Beweisgrund des Daseyns Gottes," ch. 7. Moreover, in the later work he gives us to understand that Lambert in his "Kosmologischen Briefen," 1761, tacitly adopted that doctrine from him, and these letters at the same time also appeared in French (Lettres Cosmologiques sur la Constitution de l'Univers). 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? 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 the year 1666, in a "Communication to the Royal Society," expounds it quite distinctly, although only as an hypothesis and without proof. The
