Introspection must be regarded as confined to the knowledge of immediately antecedent mental states with reference to which, no error of memory can be supposed to arise.
It follows from this that an illusion of introspection could only be found in connection with the apprehension of present or immediately antecedent mental states.

On the other hand, any illusions connected with the consciousness of personal continuity and identity would fall rather under the class of mnemonic than that of introspective error.
Once more, introspection must be carefully distinguished from what I have called belief.

Some of our beliefs may be found to grow out of and be compounded of a number of introspections.

Thus, my conception of my own character, or my psychological conception of mind as a whole, may be seen to arise by a combination of the results of a number of acts of introspection.

Yet, supposing this to be so, we must still distinguish between the single presentative act of introspection and the representative belief growing out of it.
It follows from this that, though an error of the latter sort might conceivably have its origin in one of the former; though, for example, a man's illusory opinion of himself might be found to involve errors of introspection, yet the two kinds of illusion would be sufficiently unlike.