with the recognition of a God, and the Christian
doctrine of a resurrection: in the hands of Dr. Good, it was combined
with the principles of Theism, and even with the revealed doctrine of
the separate existence of the soul during the interval between death and
the resurrection: and in the hands of Davis and the author of the
"Purpose of Existence," it is exhibited in connection with a theory of
Progression, widely different, indeed, from the doctrine of Scripture,
but equally different from the infidel speculations of the last century.
Still, with all these shades of difference, there is _that common to
all_ the forms in which it can be presented which shows that they are
radically one and the same: _they all deny the existence of any generic
difference between Matter and Mind_.

Confining our attention to this common element, and omitting the
consideration of minor diversities, we may now inquire into the grounds
on which the theory rests, and the most plausible reasons which have
been urged in support of it.

To some minds it has been recommended by its _apparent simplicity_. It
speaks only of _one_ substance as existing in Nature under various
modifications. It represents the universe, so far as created being is
concerned, as entirely composed of _matter_, more or less refined; and
thus excludes the complication which must necessarily arise from the
supposition of two substances, generically different, yet intimately and
indissolubly related. The principle, therefore, which prompts us to seek
unity in diversity, and to reduce, by some comprehensive generalization,
a multitude of phenomena under one general law, has led some to adopt
the theory of _unisubstancisme_ in preference to the opposite doctrine
of _dualism_. Not content with the generalization, alike safe and
legitimate, which ranks both mind and matter under the generic head of
_substance_, they have sought to reduce them to the same category, and
to give to matter a monopoly of the universe, at least of created being.
In support of their views, they remind us of the fundamental principle
of philosophy as laid down by Sir Isaac Newton, that "we are to admit no
more causes of things than are sufficient to explain appearances."[153]
The principle is a sound one; and the only question is, whether matter
alone is sufficient to account for mental phenomena? On _this_ question
the two parties are at irreconcilable variance; and the controversy
cannot be determi