f
Erasmus and Fontenelle.'"[250:15]

[Sidenote: Radical Materialism. Mind as an Epiphenomenon.]

Sect. 116. The extreme claim that the soul is a physical organ of the
body, identical with the brain, marked the culmination of this militant
materialism, so good an instance of that over-simplification and
whole-hearted conviction characteristic of the doctrinaire propagandism
of France. Locke, the Englishman, had admitted that possibly the
substance which thinks is corporeal. In the letters of Voltaire this
thought has already found a more positive expression:

"I am body, and I think; more I do not know. Shall I then
attribute to an unknown cause what I can so easily attribute
to the only fruitful cause I am acquainted with? In fact,
where is the man who, without an absurd godlessness, dare
assert that it is impossible for the Creator to endow matter
with thought and feeling?"[251:16]

Finally, Holbach, the great systematizer of this movement, takes the
affair out of the hands of the Creator and definitively announces that
"a sensitive soul is nothing but a human brain so constituted that it
easily receives the motions communicated to it."[251:17]

This theory has been considerably tempered since the age of Holbach.
Naturalism has latterly been less interested in identifying the soul
with the body, and more interested in demonstrating its dependence upon
specific bodily conditions, after the manner of La Mettrie. The
so-called higher faculties, such as thought and will, have been related
to central or _cortical_ processes of the nervous system, processes of
connection and complication which within the brain itself supplement the
impulses and sensations congenitally and externally stimulated. The
term "epiphenomenon" has been adopted to express the distinctness but
entire dependence of the mind. Man is "a conscious automaton." The real
course of nature passes through his nervous system, while consciousness
attends upon its functions like a shadow, present but not
efficient.[252:18]

[Sidenote: Knowledge, Positivism and Agnosticism.]

Sect. 117. Holbach's "Systeme de la Nature," published in 1770, marks
the culmination of the unequivocally materialistic form of naturalism.
Its epistemological difficulties, always more or less in evidence, have
since that day sufficed to discredit materialism, and to foster the
growth of a critical and apologetic form of naturalism known as
_positi