But the steps are fewer, and shorter, and of the self-same nature, which lead us to believe in the existence of Mind, for of that we have the evidence within ourselves."[163] It follows that were we reduced, as we are not, to the necessity of adopting the theory of "unisubstancisme," we might with at least as good reason dispense with the existence of "matter" as with the existence of "mind;" for, in the words of Dugald Stewart, "it would no more be proper to say of 'mind' that it is _material_, than to say of 'body' that it is _spiritual."_[164] III.

Our _third_ proposition is, That we are _not_ reduced to the necessity of adopting any theory of "unisubstancisme," since there is nothing inconceivable or self-contradictory in the supposition of two distinct substantive beings, possessing diverse properties, such as "mind" and "body," or "spirit" and "matter," are usually held to be.
Let any one endeavor to assign a reason for the sole, exclusive existence either of "matter" or of "spirit," or a distinct, specific ground for the opinion that they are necessarily incompatible with each other, and he will be compelled to own that the theory of "unisubstancisme," however plausible by reason of its apparent simplicity, is really nothing more than a gratuitous assumption.

It cannot be admitted with reference even to _nature_ and _man_ without confounding the simplest elements of human knowledge; and with reference to _God_ and the _universe_, it is attended with still more fatal consequences, since it must lead, if consistently followed out, to undisguised Pantheism.

Why should it be supposed that there is, or can only be, _one_ substance in Nature?
one substance invested with all those properties and powers which exist, in such manifold diversity, in the organic and inorganic kingdoms?
The wonder might rather seem to be that any _two_ substances should be capable of accounting for such a variety of phenomena as the universe exhibits.

A "dualism" is unavoidable, unless we are to materialize God as well as man; and why may there not be a "dualism" in the case of created _mind_ and _matter_, as there must be, on any supposition except that of Pantheism, in the case of the uncreated mind and the material universe?
We see variety and gradation in all the works of God; we see thousands of substances, simple and compound, possessing various properties, even in the inorganic world; we see different forms of life, vegetable and animal, ascending by steps of regular gradation, from the lowest to the highest; we see, in the animal kingdom, various propensities, instincts, and powers, which constitute the characteristics of distinct species; at length we rise to Man, with his rational, responsible, and immortal nature.