And some of these philosophers even go so far as to affirm that the plain man is quite equal to the niceties of this process.
It has been brought as a charge against some of these same philosophers that they have based certain of their doctrines on errors of introspection.

This charge must, of course, be received with some sort of suspicion here, since it has been brought forward by avowed disciples of an opposite philosophic school.

Nevertheless, as there is from our present disinterested and purely scientific point of view a presumption that philosophers like other men are fallible, and since it is certain that philosophical introspection does not materially differ from other kinds, it seems permissible just to glance at some of these alleged illusions in relation to other and more vulgar forms.

Further reference to them will be made at the end of our study.
These so-called philosophical illusions will be found, like the vulgar ones just spoken of, to illustrate the distinction drawn between passive and active illusions.

That is to say, the alleged misreading of individual consciousness would result now from a confusion of distinct elements, including wrong suggestion, due to the intricacies of the phenomena, now from a powerful predisposition to read something into the phenomena.
A kind of illusion in which the passive element seems most conspicuous would be the error into which the interrogator of the individual consciousness is said to fall respecting simple unanalyzable states of mind.