things "entering into the mind" and yet remaining what they were before they entered it. (It is really too primitive a picture to compare consciousness to a box into which objects could be put and taken out. And we had already convinced ourselves a few minutes ago that one can never say that the same content is here and there; "in" the mind and "outside" of it, for whatever we say will express structure only. By the way, the words "consciousness" and "mind" are so treacherous that practically all philosophical sentences in which they occur are devoid of sense. I should like to go so far as to say that these terms have a good, honest, definable meaning only in the common use of ordinary language, as when I say "he has an acute mind" or "she lost consciousness").
But however this may be, I think it has become clear now, why idealism is the preferred form of metaphysics: the metaphysician is hunting for content (calling the "real essence of being" or the "intrinsic nature of things" etc.) he finds it only in his own perceptions, feelings, ideas (calling them mental), and so he triumphantly pronounces the fundamental principle of idealism: "the inner nature of everything is mental" — which we have just seen to be a meaningless chain of words.
It is hardly necessary to add that other metaphysical systems, such as dualism, or materialism are no better. It is easy to see from the arguments pro and contra these views (which fill our philosophical test books) that both materialists and dualists (and whatever other varieties of metaphysicians there may be) believe they are telling us something about content. It is not quite easy to see in which way the word "matter" (signifying physical substance) could be regarded as denoting content — and that is why materialistic metaphysics has in general stood in smaller favour than idealism — but there is no doubt that it was meant this way from the time of Democritus on. The essential characteristic of his material atoms was that they occupied space, and since in earlier times the distinction between physical space and the intuitive spaces could, of course, not be made, the filling of space was regarded as content with which we were directly acquainted.
But we need not here carry the criticism of metaphysical systems and the attempt to understand their mistakes any further; it is time to draw the important positive conclusions from our result that all knowledge is expression, and that all expression is a rendering of structure, not of content.
