re very
similar, and each instance consists of a series of movements in the
mouth.

A single word, accordingly, is by no means simple it is a class of
similar series of movements (confining ourselves still to the spoken
word). The degree of similarity required cannot be precisely defined:
a man may pronounce the word "Napoleon" so badly that it can hardly be
determined whether he has really pronounced it or not. The instances
of a word shade off into other movements by imperceptible degrees. And
exactly analogous observations apply to words heard or written or read.
But in what has been said so far we have not even broached the
question of the DEFINITION of a word, since "meaning" is clearly what
distinguishes a word from other sets of similar movements, and "meaning"
remains to be defined.

It is natural to think of the meaning of a word as something
conventional. This, however, is only true with great limitations. A new
word can be added to an existing language by a mere convention, as
is done, for instance, with new scientific terms. But the basis of
a language is not conventional, either from the point of view of the
individual or from that of the community. A child learning to speak is
learning habits and associations which are just as much determined by
the environment as the habit of expecting dogs to bark and cocks to
crow. The community that speaks a language has learnt it, and modified
it by processes almost all of which are not deliberate, but the results
of causes operating according to more or less ascertainable laws. If
we trace any Indo-European language back far enough, we arrive
hypothetically (at any rate according to some authorities) at the stage
when language consisted only of the roots out of which subsequent words
have grown. How these roots acquired their meanings is not known, but a
conventional origin is clearly just as mythical as the social contract
by which Hobbes and Rousseau supposed civil government to have been
established. We can hardly suppose a parliament of hitherto speechless
elders meeting together and agreeing to call a cow a cow and a wolf a
wolf. The association of words with their meanings must have grown up
by some natural process, though at present the nature of the process is
unknown.

Spoken and written words are, of course, not the only way of conveying
meaning. A large part of one of Wundt's two vast volumes on language in
his "Volkerpsychologie" is concerned with ges