Many persons, especially women and intelligent children, take
pleasure in introspection, and strive their very best to explain
their mental processes. I think that a delight in self-dissection
must be a strong ingredient in the pleasure that many are said to
take in confessing themselves to priests.

Here, then, are two rather notable results: the one is the proved
facility of obtaining statistical insight into the processes of
other persons' minds, whatever _à priori_ objection may have been
made as to its possibility; and the other is that scientific men, as
a class, have feeble powers of visual representation. There is no
doubt whatever on the latter point, however it may be accounted for.
My own conclusion is, that an over-ready perception of sharp mental
pictures is antagonistic to the acquirement of habits of
highly-generalised and abstract thought, especially when the steps
of reasoning are carried on by words as symbols, and that if the
faculty of seeing the pictures was ever possessed by men who think
hard, it is very apt to be lost by disuse. The highest minds are
probably those in which it is not lost, but subordinated, and is
ready for use on suitable occasions. I am, however, bound to say,
that the missing faculty seems to be replaced so serviceably by other
modes of conception, chiefly, I believe, connected with the
incipient motor sense, not of the eyeballs only but of the muscles
generally, that men who declare themselves entirely deficient in the
power of seeing mental pictures can nevertheless give life-like
descriptions of what they have seen, and can otherwise express
themselves as if they were gifted with a vivid visual imagination.
They can also become painters of the rank of Royal Academicians.

The facts I am now about to relate are obtained from the returns of