losophy and Psychology.%

In Locke's famous countryman, Isaac Newton (1642-1727),[1] the modern
investigation of nature attains the level toward which it had striven, at
first by wishes and demands, gradually, also, in knowledge and achievement,
since the end of the mediaeval period. Mankind was not able to discard at
a stroke its accustomed Aristotelian view of nature, which animated things
with inner, spirit-like forces. A full century intervened between Telesius
and Newton, the concept of natural law requiring so long a time to break
out of its shell. A tremendous revolution in opinion had to be effected
before Newton could calmly promulgate his great principle, "Abandon
substantial forms and occult qualities and reduce natural phenomena to
mathematical laws," before he could crown the discoveries of Galileo and
Kepler with his own. For this successful union of Bacon's experimental
induction with the mathematical deduction of Descartes, this combination of
the analytic and the synthetic methods, which was shown in the demand
for, and the establishment of, mathematically formulated natural laws,
presupposes that nature is deprived of all inner life [2] and all
qualitative distinctions, that all that exists is compounded of uniformly
acting parts, and that all that takes place is conceived as motion. With
this Hobbes's programme of a mechanical science of nature is fulfilled. The
heavens and the earth are made subject to the same law of gravitation. How
far Newton himself adhered to the narrow meaning of mechanism (motion from
pressure and impulse), is evident from the fact that, though he is often
honored as the creator of the dynamical view of nature, he rejected _actio
in distans_ as absurd, and deemed it indispensable to assume some "cause"
of gravity (consisting, probably, in the impact of imponderable material
particles). It was his disciples who first ventured to proclaim gravity as
the universal force of matter, as the "primary quality of all bodies" (so
Roger Cotes in the preface to the second edition of the _Principia_, 1713).

[Footnote 1: 1669-95 professor of mathematics in Cambridge, later resident
in London; 1672, member, and, 1703, president of the Royal Society. Chief
work, _Philosophic Naturalis Principia Mathematica_, 1687. _Works_, 1779
_seq_. On Newton cf. K. Snell, 1843; Durdik, _Leibniz und Newton_, 1869;
Lange, _History of Materialism_, vol. i. p. 306 _seq_.]

[Footnote 2: That the mathematical v