nterpretation
of inner phenomena, pointing out that the heterogeneity of motion and ideas
forbids the reduction of the latter to the former, and that psychological
analysis never reaches corporeal but only psychical elements. Moreover, it
is only with reluctance that, conscious of the critical character of the
conclusion, he admits the dependence of brain vibrations on the mechanical
laws of the material world and the thoroughgoing determinateness of the
human will, consoling himself with the belief that moral responsibility
nevertheless remains intact. Priestley, on the contrary, boldly avows the
materialistic and deterministic consequences of his position, holds that
psychical phenomena are not merely accompanied by material motions but
consist in them (thought is a function of the brain), and makes psychology,
as the physics of the nerves, a part of physiology. The denial of
immortality and the divine origin of the world is, however, by no means
to follow from materialism. Priestley not only combated the atheism of
Holbach, but also entered the deistic ranks with works of his own on
Natural Religion and the Corruptions of Christianity.

[Footnote 1: Hartley, _Observations on Man, his Frame, his Duties, his
Expectations_. 1749.]

[Footnote 2: Priestley, _Hartley's Theory of the Human Mind on the
Principles of the Association of Ideas_, 1775; _Disquisitions relating to
Matter and Spirit_, 1777; _The Doctrine of Philosophical Necessity_, 1777;
_Free Discussions of the Doctrines of Materialism_, 1778 (against Richard
Price's _Letters on Materialism and Philosophical Necessity_). Cf. on
both Schoenlank's dissertation, _Hartley und Priestley, die Begruender des
Assoziationismus in England_, 1882.]

As early as in Hartley[1] the principle, which is so important for ethics,
appears that things and actions (_e.g._, promotion of the good of others)
which at first are sought and done because they are means to our own
enjoyment, in time come to have a direct worth of their own, apart from the
original egoistic end. James Mill (1829) has repeated this thought in later
times. As fame becomes an immediate object of desire to the ambitious man,
and gold to the miser, so, through association, the impulse toward that
which will secure approval may be transformed into the endeavor after that
which deserves approval.

[Footnote 1: Cf. Jodl, _Geschichte der Ethik_, vol. i. p. 197 _seq_.]

Among later representatives of the Associatio