For those at the present day who unfeignedly accept the general principles of evolution and philosophise from them, a dualistic philosophy is impossible. They cannot hold that matter is subject to evolution and that mind is not; and the continuity of the process of evolution forbids us to suppose that there is any real discontinuity between that which appears at one stage as matter and at another as mind. There is no discontinuity if material things (_i.e._ the things of which we have sense-perception, but which differ from our sensations in being permanent) are on the one side the permanent expressions of Will and on the other are the transient impressions made on us in the shape of sense-phenomena. What is true thus of the content of evolution, of that which is in process of evolution, is true also of the law of the process. We cannot suppose that it extends only to matter--that the behaviour of matter is susceptible of a rational explanation and the behaviour of mind is not. The continuity of the process excludes the possibility of a dual control: either the power which manifests itself in all things is intelligent throughout or it is not. If there is no reason in the behaviour of things, but only necessity, then those human actions and conceptions which man considers to be the result of his reason are really the result of unintelligent necessity. It is the latter hypothesis which is expressed by the necessitarian theory. The ordinary belief of mankind--a belief which it is impossible to resist at the moment when you are making up your mind whether you will do this or not--is that you _can_ do the thing or not, that the alternatives are real and the motives such that either of them may be acted on. The necessitarian hypothesis is that the alternatives are not real, that even before you have made up your mind there is only one alternative which you can follow--the other courses are only apparent alternatives, because you cannot choose or act on any of them; the other motives are not real motives, because by a necessity dating from the beginning of things they cannot possibly influence you on this occasion. Your action is as automatic as that of a piano which responds to the touch. The difference is that you think about the stimulus received and the piano does not. Consequently the piano makes no mistakes; you make two. You think of various possible consequences of the stimulus--which are all impossible--and you imagine that the one which you choose is the consequence of your intelligent choice, whereas it is the automatic outcome of that iron law of necessity which binds together the whole process of evolution.