CHAPTER VIII.
ILLUSIONS OF INTROSPECTION.
We have now, perhaps, sufficiently reviewed sense-illusions, both of waking life and of sleep.

And having roughly classified them according to their structure and origin, we are ready to go forwards and inquire whether the theory thus reached can be applied to other forms of illusory error.

And here we are compelled to inquire at the outset if anything analogous to sense-illusion is to be found in that other great region of presentative cognition usually marked off from external perception as internal perception, self-reflection, or introspection.
_Illusions of Introspection defined._ This inquiry naturally sets out with the question: What is meant by introspection?
This cannot be better defined, perhaps, than by saying that it is the mind's immediate reflective cognition of its own states as such.
In one sense, of course, everything we know may be called a mental state, actual or imagined.

Thus, a sense-impression is known, exactly like any other feeling of the mind, as a mental phenomenon or mental modification.

Yet we do not usually speak of introspectively recognizing a sensation.