_Another variety of the psychologist's fallacy is the assumption that the mental state studied must be conscious of itself as the psychologist is conscious of it._ The mental state is aware of itself only from within; it grasps what we call its own content, and nothing more. The psychologist, on the contrary, is aware of it from without, and knows its relations with all sorts of other things. What the thought sees is only its own object; what the psychologist sees is the thought's object, plus the thought itself, plus possibly all the rest of the world. We must be very careful therefore, in discussing a state of mind from the psychologist's point of view, to avoid foisting into its own ken matters that are only there for ours. We must avoid substituting what we know the consciousness _is_, for what it is a consciousness _of_, and counting its outward, and so to speak physical, relations with other facts of the world, in among the objects of which we set it down as aware. Crude as such a confusion of standpoints seems to be when abstractly stated, it is nevertheless a snare into which no psychologist has kept himself at all times from falling, and which forms almost the entire stock-in-trade of certain schools. We cannot be too watchful against its subtly corrupting influence. _Summary_. To sum up the chapter, Psychology assumes that thoughts successively occur, and that they know objects in a world which the psychologist also knows. _These thoughts are the subjective data of which he treats, and their relations to their objects, to the brain, and to the rest of the world constitute the subject-matter of psychologic science._ Its methods are introspection, experimentation, and comparison. But introspection is no sure guide to truths _about_ our mental states; and in particular the poverty of the psychological vocabulary leads us to drop out certain states from our consideration, and to treat others as if they knew themselves and their objects as the psychologist knows both, which is a disastrous fallacy in the science. FOOTNOTES: [187] On the relation between Psychology and General Philosophy, see G. C. Robertson, 'Mind,' vol. viii, p. 1, and J. Ward, _ibid._ p. 153; J. Dewey _ibid._ vol. ix, p. 1. [188] Compare some remarks in Mill's Logic, bk. i, chap. iii, §§ 2, 3. [189] Logic, § 40. [190] Psychologie, bk. ii, chap. iii, §§ 1, 2. [191] Cours de Philosophie Positive, i, 34-8. [192] Auguste Comte and Positivism, 3d edition (1882), p. 64.