Of certain fallacies to which the psychologist is exposed by reason of his peculiar point of view--that of being a reporter of subjective as well as of objective facts, we must presently speak. But not until we have considered the methods he uses for ascertaining what the facts in question are. THE METHODS OF INVESTIGATION. _Introspective Observation is what we have to rely on first and foremost and always._ The word introspection need hardly be defined--it means, of course, the looking into our own minds and reporting what we there discover. _Every one agrees that we there discover states of consciousness._ So far as I know, the existence of such states has never been doubted by any critic, however sceptical in other respects he may have been. That we have _cogitations_ of some sort is the _inconcussum_ in a world most of whose other facts have at some time tottered in the breath of philosophic doubt. All people unhesitatingly believe that they feel themselves thinking, and that they distinguish the mental state as an inward activity or passion, from all the objects with which it may cognitively deal. _I regard this belief as the most fundamental of all the postulates of Psychology,_ and shall discard all curious inquiries about its certainty as too metaphysical for the scope of this book. * * * * * _A Question of Nomenclature._ We ought to have some general term by which to designate all states of consciousness merely as such, and apart from their particular quality or cognitive function. Unfortunately most of the terms in use have grave objections. 'Mental state,' 'state of consciousness,' 'conscious modification,' are cumbrous and have no kindred verbs. The same is true of 'subjective condition.' 'Feeling' has the verb 'to feel,' both active and neuter, and such derivatives as 'feelingly,' 'felt,' 'feltness,' etc., which make it extremely convenient. But on the other hand it has specific meanings as well as its generic one, sometimes standing for pleasure and pain, and being sometimes a synonym of '_sensation_' as opposed to _thought_; whereas we wish a term to cover sensation and thought indifferently. Moreover, 'feeling' has acquired in the hearts of platonizing thinkers a very opprobrious set of implications; and since one of the great obstacles to mutual understanding in philosophy is the use of words eulogistically and disparagingly, impartial terms ought always, if possible, to be preferred. The word _psychosis_ has been proposed by Mr. Huxley. It has the advantage of being correlative to _neurosis_ (the name applied by the same author to the corresponding nerve-process), and is moreover technical and devoid of partial implications. But it has no verb or other grammatical form allied to it. The expressions 'affection of the soul,' 'modification of the ego,' are clumsy, like 'state of consciousness,' and they implicitly assert theories which it is not well to embody in terminology before