least to the extent of showing that the existence of "matter," as a thing external to us, cannot be proved without presupposing the existence of "mind." "For what," says Lord Brougham, "is this matter? Whence do we derive any knowledge of it? How do we assure ourselves of its existence? What evidence have we at all respecting either its being or its qualities? We feel, or taste, or smell something; that is, we have certain sensations, which make us conclude that something exists beyond ourselves." ... "But what are our sensations? The feelings or thoughts of our own minds. Then what we do is this: from certain ideas in our minds, produced no doubt by, and connected with, our bodily senses, but independent of and separate from them, we draw certain conclusions by reasoning; and these conclusions are in favor of the existence of something other than our sensations and our reasonings, and other than that which experiences the sensations and makes the reasonings, passive in the one case, active in the other. That something is what we call--Mind. But plainly, whatever it is, we owe to it the knowledge that matter exists; for that knowledge is gained by means of a sensation or feeling, followed by a process of reasoning; it is gained by the mind having first suffered something, and then done something. Therefore, to say _there is no such thing as matter_ would be a much less absurd inference than to say _there is no such thing as mind_." ... "The truth is, that we believe in the existence of 'matter,' because we cannot help it. The inferences of our reason from our sensations impel us to this conclusion, and the steps are few and short by which we reach it. 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.