lf to the irksome
effort of attention--without passion he would remain stupid. The sum of
ideas collected in him is called intellect. All distinctions among men
are acquired, and concern the intellect only, not the soul: that which is
innate--sensibility and self-love--is the same in all; differences arise
only through external circumstances, through education. Man is the pupil of
all that environs him, of his situation and his chance experience. The most
important instrument in education is the law; the function of the lawgiver
is to connect public and personal welfare by means of rewards and
punishments, and thus to elevate morality. A man is called virtuous when
his stronger passions harmonize with the general interest. Unfortunately
the virtues of prejudice, which do not contribute to the public good, are
more honored among most nations than the political virtues, to which alone
real merit belongs. And self-interest is always the one motive to just and
generous action; we serve only our own interests in furthering the welfare
of the community. As the promulgator of these doctrines was himself a kind
and generous man, Rousseau could make to him the apt reply: You endeavor in
vain to degrade yourself below your own level; your spirit gives evidence
against your principles; your benevolent heart discredits your doctrines.

The morality of enlightened self-love or "intelligent self-interest"
appears in a milder form in Maupertuis (_Works_, 1752), and Frederick the
Great,[1] to the latter of whom D'Alembert objected by letter that interest
could never generate the sense of duty and reverence for the law.

[Footnote 1: _Essay on Self-love as a Principle of Morals_, 1770, printed
in the proceedings of the Academy of Sciences. Cf. on Frederick, Ed.
Zeller, 1886.]

%3. Skepticism and Materialism.%

The ideas thus far developed move in a direction whose further pursuit
inevitably issues in materialism. Diderot, the editor of the _Encyclopedia
of the Sciences, Arts, and Trades_ (1751-72), which gathered all the
currents of the Illumination into one great stream and carried them to the
open sea of popular culture, reflects in his intellectual development
the dialectical movement from deism through skepticism to atheism and
materialism, and was a co-laborer in the work which brought the whole
movement to a conclusion, Holbach's _System of Nature_. Two decades,
however, before the latter work, the outcome of a long developmen