Chapter 18

CONCLUSION.

A few more pages must be given to one or two of Diderot's writings which have not hitherto been mentioned. An exhaustive survey of his works is out of the question, nor would any one be repaid for the labour of criticism. A mere list of the topics that he handled would fill a long chapter. A redaction of a long treatise on harmony, a vast sheaf of notes on the elements of physiology, a collection of miscellanea on the drama, a still more copious collection of miscellanea on a hundred points in literature and art, a fragment on the exercise of young Russians, an elaborate plan of studies for a proposed Russian University,--no less panurgic and less encyclopædic a critic than Diderot himself could undertake to sweep with ever so light a wing over this vast area. Everybody can find something to say about the collection of tales, in which Diderot thought that he was satirising the manners of his time, after the fashion of Rabelais, Montaigne, La Mothe-le-Vayer, and Swift. But not everybody is competent to deal, for instance, with the five memoirs on different subjects in mathematics (1748), with which Diderot hoped to efface the scandal of his previous performance.

I.

Decidedly the most important of the pieces of which we have not yet spoken must be counted the _Thoughts on the Interpretation of Nature_ (1754). His study of Bacon and the composition of the introductory prospectus of the Encyclopædia had naturally filled Diderot's mind with ideas about the universe as a whole. The great problem of man's knowledge of this universe,--the limits, the instruments, the meaning of such knowledge, came before him with a force that he could not evade. Maupertuis had in 1751, under the assumed name of Baumann, an imaginary doctor of Erlangen, published a dissertation on the _Universal System of Nature_, in which he seems to have maintained that the mechanism of the universe is one and the same throughout, modifying itself, or being modified by some vital element within, in an infinity of diverse ways.[207] Leibnitz's famous idea, of making nature invariably work with the minimum of action, was seized by Maupertuis, expressed as the Law of Thrift, and made the starting-point of speculations that led directly to Holbach and the _System of Nature_.[208] The _Loi d'Epargne_ evidently tended to make unity of all the forces of the universe the keynote or the goal of philosophical inquiry. At this time of his life, Diderot resisted Maupertuis's theory of the unity of vital force in the universe, or perhaps we should rather say that he saw how open it was to criticism. His resistance has none of his usual air of vehement conviction. However that may be, the theory excited his interest, and fitted in with the train of meditation which his thoughts about the Encyclopædia had already set in motion, and of which the _Pensées Philosophiques_ of 1746 were the cruder prelude.

[207] As to the precise drift of Maupertuis's theme, see Lange, _Gesch. d. Materialismus_, i. 413, _n._ 37. Also Rosenkranz, i. 134.

[208] In 1765 Grimm describes the principle of Leibnitz and Maupertuis as "gaining on us on every side."--_Corr. Lit._, iv. 186.

The _Thoughts on the Interpretation of Nature_ are, in form as in title, imitated from those famous _Aphorismi de Interpretatione Naturæ et Regni Hominis_, which are more shortly known to all men as Bacon's _Novum Organum_.[209] The connection between the aphorisms is very loosely held. Diderot began by premising that he would let his thoughts follow one another under his pen, in the order in which the subjects came up in his mind; and he kept his word. Their general scope, so far as it is capable of condensed expression, may be described as a reconciliation between the two great classes into which Diderot found thinkers upon Nature to be divided; those who have many instruments and few ideas, and those who have few instruments and many ideas,--in other words, between men of science without philosophy, and philosophers without knowledge of experimental science.

[209] Palissot, in the _Philosophers_, concocted some very strained satire on the too pompous opening of the _Interpretation of Nature_.