Now it is very evident that Dr. McCosh, in his anxiety to prove an extra-mental world, is actuated by a desire to retain real things. He is under the impression that, unless the extra-mental is known, our knowledge is confined to shadows and unrealities. He combats the Idealist, because he supposes him to deny the body of which we are conscious; whereas, all that the Idealist is denying (if he be consistent with his principles) is the hypothetical representative of the body, assumed to exist within the body, and to which consciousness does not testify. It is this that is the unreality. The body to which the Idealist holds is the very body to which Dr. McCosh thinks consciousness testifies; but this body is not beyond consciousness, nor in any proper sense of the words extra-mental. The above argument for the extra-mental is consequently due to a misconception--to the misconception that the body revealed by consciousness is the extra-mental body, and that the only body left to an Idealist is an unreal phantom of this body, and distinct from it. And it is the attempt to make this body revealed by consciousness both in mind and out of mind that has occasioned the difficulties and inconsequences of the reasoning I have quoted. This attempt is due to a confusion of sameness in sense seventh with sameness in sense first. My excuse for so minute a criticism of this plainly untenable position is that we have here a representative instance of an error quite common, and indeed characteristic of a certain stage of reflection. SEC. 36. The last confusion of samenesses that I shall discuss lies at the bottom of the common opinion on the infinite divisibility of space, and causes the antinomies which arise from it. The position I shall criticize is well set forth in Professor W. K. Clifford's popular lecture entitled "Of Boundaries in General."[72] From this I take a few passages which will suffice to illustrate his doctrine. [72] "Seeing and Thinking," London, Macmillan & Co., 1879.