ant by "understanding" words and sentences, let
us take instances of various situations.

Suppose you are walking in London with an absent-minded friend, and
while crossing a street you say, "Look out, there's a motor coming."
He will glance round and jump aside without the need of any "mental"
intermediary. There need be no "ideas," but only a stiffening of the
muscles, followed quickly by action. He "understands" the words, because
he does the right thing. Such "understanding" may be taken to belong to
the nerves and brain, being habits which they have acquired while the
language was being learnt. Thus understanding in this sense may be
reduced to mere physiological causal laws.

If you say the same thing to a Frenchman with a slight knowledge of
English he will go through some inner speech which may be represented by
"Que dit-il? Ah, oui, une automobile!" After this, the rest follows as
with the Englishman. Watson would contend that the inner speech must be
incipiently pronounced; we should argue that it MIGHT be merely imaged.
But this point is not important in the present connection.

If you say the same thing to a child who does not yet know the word
"motor," but does know the other words you are using, you produce a
feeling of anxiety and doubt you will have to point and say, "There,
that's a motor." After that the child will roughly understand the word
"motor," though he may include trains and steam-rollers If this is the
first time the child has heard the word "motor," he may for a long time
continue to recall this scene when he hears the word.

So far we have found four ways of understanding words:

(1) On suitable occasions you use the word properly.

(2) When you hear it you act appropriately.

(3) You associate the word with another word (say in a different
language) which has the appropriate effect on behaviour.

(4) When the word is being first learnt, you may associate it with an
object, which is what it "means," or a representative of various objects
that it "means."

In the fourth case, the word acquires, through association, some of the
same causal efficacy as the object. The word "motor" can make you
leap aside, just as the motor can, but it cannot break your bones. The
effects which a word can share with its object are those which proceed
according to laws other than the general laws of physics, i.e. those
which, according to our terminology, involve vital movements as opposed
to merely me