widely held, and which I formerly held myself: the theory that
the essence of everything mental is a certain quite peculiar
something called "consciousness," conceived either as a relation
to objects, or as a pervading quality of psychical phenomena.

The reasons which I shall give against this theory will be mainly
derived from previous authors. There are two sorts of reasons,
which will divide my lecture into two parts

(1) Direct reasons, derived from analysis and its difficulties;

(2) Indirect reasons, derived from observation of animals
(comparative psychology) and of the insane and hysterical
(psycho-analysis).

Few things are more firmly established in popular philosophy than
the distinction between mind and matter. Those who are not
professional metaphysicians are willing to confess that they do
not know what mind actually is, or how matter is constituted; but
they remain convinced that there is an impassable gulf between
the two, and that both belong to what actually exists in the
world. Philosophers, on the other hand, have maintained often
that matter is a mere fiction imagined by mind, and sometimes
that mind is a mere property of a certain kind of matter. Those
who maintain that mind is the reality and matter an evil dream
are called "idealists"--a word which has a different meaning in
philosophy from that which it bears in ordinary life. Those who
argue that matter is the reality and mind a mere property of
protoplasm are called "materialists." They have been rare among
philosophers, but common, at certain periods, among men of