nge is obviously much greater than that of the previously
considered classes of presentative illusion. This is, indeed, involved
in what has been said about the nature of the process. Insight, as we
have seen, though here classed with preservative cognition, occupies a
kind of border-land between immediate knowledge or intuition and
inference, shading off from the one to the other. And in the very nature
of the case the scope for error must be great. Even overlooking human
reticence, and, what is worse, human hypocrisy, the conditions of an
accurate reading of others' minds are rarely realized. If, as has been
remarked by a good authority, one rarely meets, even among intelligent
people, with a fairly accurate observer of external things, what shall
be said as to the commonly claimed power of "intuitive insight" into
other people's thoughts and feelings, as though it were a process above
suspicion? It is plain, indeed, on a little reflection, that, taking
into account what is required in the way of large and varied experience
(personal and social), a habit of careful introspection, as well as a
habit of subtle discriminative attention to the external signs of mental
life, and lastly, a freedom from prepossession and bias, only a very few
can ever hope even to approximate to good readers of character.

And then we have to bear in mind that this large amount of error is apt
to remain uncorrected. There is not, as in the case of external
perception, an easy way of verification, by calling in another sense; a
misapprehension, once formed, is apt to remain, and I need hardly say
that errors in these matters of mutual comprehension have their palpable
practical consequences. All social cohesion and co-operation rest on
this comprehension, and are limited by its degree of perfection. Nay,
more, all common knowledge itself, in so far as it depends on a mutual
communication of impressions, ideas, and beliefs, is limited by the
fact of this great liability to error in what at first seems to be one
of the most certain kinds of knowledge.

In view of this depressing amount of error, our solace must be found in
the reflection that this seemingly perfect instrument of intuitive
insight is, in reality, like that of introspection, in process of being
fashioned. Mutual comprehension has only become necessary since man
entered the social state, and this, to judge by the evolutionist's
measure of time, is not so long ago. A mental structu