is the doctrine of Materialism? What are the forms in which
it has appeared, and what the ground on which it rests? How does it
stand related to the question concerning the nature and existence of
God, or the constitution and destiny of Man? A brief answer to these
questions will be sufficient to show that this theory cannot be safely
disregarded in any attempt to construct a comprehensive and conclusive
argument on the first principles of Natural Theology.

SECTION I.

DISTINCT FORMS OF MATERIALISM.

The doctrine of Materialism has assumed several distinct phases or forms
in the hands of its different advocates; and these must be carefully
discriminated from each other, if we would either estimate aright their
respective merits, or do justice to the parties by whom they have been
severally maintained.

The grossest and most revolting form of Materialism is that which
_identifies mind with matter_, and _thought with motion_. It denies that
there is any real or radical difference between physical and moral
phenomena, and affirms that life and thought are so entirely dependent
on material organization, that the dissolution of the body must
necessarily be the destruction of conscious existence, and that death
can only be an eternal sleep. This is the doctrine of Materialism which
was taught in a former age, by the author of the "Systeme de la Nature,"
and which has recently been revived by M. Comte in France, and by
Atkinson and Martineau in England. A few extracts will sufficiently
illustrate its character and tendency. "Men have evidently abused the
distinction," says Baron D'Holbach, "which is so often made between _man
physical_ and _man moral_: man moral is nothing else than that physical
being considered in a certain point of view, that is, with reference to
some modes of action which belong to his peculiar organization."--"The
universe--that vast assemblage of everything that exists--exhibits
nowhere anything else than _matter and motion_."--"If we are asked, what
is man? we reply, that he is a material being, organized or framed so as
to feel, to think, and to be affected in certain ways peculiar to
himself, according to his organization."[147] More recently, M. Comte
has affirmed that "the subject of all our researches is _one_," and that
"all natural phenomena are the necessary results either of the laws of
extension or of the laws of motion;" while M. Crousse is quite clear
that "intelligence is a property