But in addition to this scientific psychology, there is another so-called psychology, which is, strictly speaking, philosophic.  This, I need hardly say, is the association philosophy.  It proceeds by analyzing certain cognitions and sentiments into their elements, and straightway declaring that they mean nothing more than these.  That is to say, the associationist passes from genesis to validity, from the history of a conscious state to its objective meaning.  Thus, from showing that an intuitive belief, say that in causation, is not original (in the individual or at least in the race), it goes on to assert that it is not a valid immediate cognition at all.  Now, I am not concerned here to inquire into the logical value of this transition, but simply to point out that it is extra-scientific and distinctly philosophic.  If logically justifiable, it is so because of some plainly philosophic assumption, as that made by Hume, namely, that all ideas not derived from impressions are to this extent fictitious or illusory.

And now we are in a position to understand the bearing of our scientific analysis of acknowledged illusions on the associationist’s treatment of the alleged illusions of common sense.  There is no doubt, I think, that some of the so-called intuitions of common sense have points of analogy to acknowledged illusions.  For example, the conviction in the act of perception that something external to the mind and independent of it exists, has a certain superficial resemblance to an hallucination of sense; and moreover, the associationist seeks to explain it by means of these very processes which underlie what is recognized by all as sense-illusion.[158] Again, it may be said that our notions of force and of a causal nexus in the physical world imply the idea of conscious energy as known through our muscular sensations, and so have a suspicious resemblance to those anthropomorphic illusions of which I have spoken under Illusions of Insight.  Once more, the consciousness of freedom may, as I have suggested, be viewed as analogous in its form and its mode of origin to illusions of introspection.  As a last example, it may be said that the mind’s certain conviction of the innateness of some of its ideas resembles those illusions of memory which arise through an inability to think ourselves back into a remote past having a type of consciousness widely unlike that of the present.

But now, mark the difference.  In our scientific analysis of popularly known illusions, we had something by which to determine the illusory character of the presentation or belief.  We had a popularly or scientifically accepted standard of certainty, by a reference to which we might test the particular soi-disant cognition.  But in the case of these fundamental beliefs we have no such criterion, except we adopt some particular philosophic theory, say that of the associationist himself.  Hence this similarity in structure and origin cannot in itself be said to amount to a proof of equality of logical or objective value.  Here again it must be remarked that origin, does not carry validity or invalidity with it.[159]