You now understand why it is that we have avoided the term ‘consciousness.’ If we had said that _red_ is an elementary conscious process, then you might have supposed that it is an elementary process in or by which you become aware of a red object; whereas, if we say that _red_ is an elementary mental process, you have no reason to think of the red object, since ‘to become mental of a red object’ is not English. It is very likely, all the same, that you _have_ been thinking of the object of knowledge, in spite of the terminology of the book, and in spite of the express warning that science has nothing to do with values or meanings or uses; the statements of a text-book, however emphatic they are, cannot always make headway against ingrained habits of thought and speech. If, then, you have at any point fallen into this mistake (and it may comfort you to know that the author, in his first years of studentship, was trapped by it again and again), go back now and read over the chapters in point; and if you discover that the mistake was partly due to the language there employed, remember that authors are human and that words are very slippery things. So much of consciousness: what, now, shall we say of the =subconscious=? The term is fashionable; and though we have nowhere used it, we can hardly pass it by without mention. The subconscious may be defined as _an extension of the conscious beyond the limits of observation_. As an extension of the _conscious_, it tends always to be an extension of meaning beyond the _meaning_ of the conscious; we do not hear of a ‘submental.’ As an _extension_ of the conscious, it is always a matter of _inference_; what we cannot observe, we must infer. So there needs no argument to prove that the subconscious is not a part of the subject-matter of psychology. How, then, does it come into psychology?