with the forces of nature. Both owe their philosophical
appeal to their apparent success in unifying the world upon a direct
empirical basis, and to their provision for the practical sense of
reality.

Such, in brief, are the main alternatives available for a naturalistic
theory of being, in consequence of the historical development of the
fundamental conceptions of natural science.

[Sidenote: The Claims of Naturalism.]

Sect. 109. We turn now to an examination of the manner in which
naturalism, equipped with working principles, seeks to meet the special
requirements of philosophy. The conception of the unity of nature is
directly in the line of a purely scientific development, but naturalism
takes the bold and radical step of regarding nature so unified as
coextensive with the real, or at any rate knowable, universe. It will be
remembered that among the early Greeks Anaxagoras had referred the
creative and formative processes of nature to a non-natural or rational
agency, which he called the _Nous_. The adventitious character of this
principle, the external and almost purely nominal part which it played
in the actual cosmology of Anaxagoras, betrayed it into the hands of
the atomists, with their more consistently naturalistic creed. Better,
these maintain, the somewhat dogmatic extension of conceptions proved to
be successful in the description of nature, than a vague dualism which
can serve only to distract the scientific attention and people the world
with obscurities. There is a remarkable passage in Lucretius in which
atomism is thus written large and inspired with cosmical eloquence:

"For verily not by design did the first-beginnings of things
station themselves each in its right place guided by keen
intelligence, nor did they bargain sooth to say what motions
each should assume, but because many in number and shifting
about in many ways throughout the universe, they are driven
and tormented by blows during infinite time past, after trying
motions and unions of every kind at length they fall into
arrangements such as those out of which our sum of things has
been formed, and by which too it is preserved through many
great years, when once it has been thrown into the appropriate
motions, and causes the streams to replenish the greedy sea
with copious river waters, and the earth, fostered by the heat
of the sun, to renew its produce, and the race