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 encyclopaedic 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 Encyclopaedia 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
Encyclopaedia had already set in motion, and of which the _Pensees
Philosophiques_ of 1746 were the cruder prelude.

[207] As to the precise drift of Maup