s that we acquire in all of them there has been present
throughout some instinctive activity, prompting at first rather
inefficient movements, but supplying the driving force while more and
more effective methods are being acquired. A cat which is hungry smells
fish, and goes to the larder. This is a thoroughly efficient method when
there is fish in the larder, and it is often successfully practised by
children. But in later life it is found that merely going to the larder
does not cause fish to be there; after a series of random movements it
is found that this result is to be caused by going to the City in the
morning and coming back in the evening. No one would have guessed a
priori that this movement of a middle-aged man's body would cause fish
to come out of the sea into his larder, but experience shows that it
does, and the middle-aged man therefore continues to go to the City,
just as the cat in the cage continues to lift the latch when it has once
found it. Of course, in actual fact, human learning is rendered easier,
though psychologically more complex, through language; but at bottom
language does not alter the essential character of learning, or of the
part played by instinct in promoting learning. Language, however, is a
subject upon which I do not wish to speak until a later lecture.

* "Mind in Evolution" (Macmillan, 1915), pp. 236-237.

The popular conception of instinct errs by imagining it to be infallible
and preternaturally wise, as well as incapable of modification. This is
a complete delusion. Instinct, as a rule, is very rough and ready, able
to achieve its result under ordinary circumstances, but easily misled by
anything unusual. Chicks follow their mother by instinct, but when they
are quite young they will follow with equal readiness any moving
object remotely resembling their mother, or even a human being (James,
"Psychology," ii, 396). Bergson, quoting Fabre, has made play with the
supposed extraordinary accuracy of the solitary wasp Ammophila, which
lays its eggs in a caterpillar. On this subject I will quote from
Drever's "Instinct in Man," p. 92:

"According to Fabre's observations, which Bergson accepts, the Ammophila
stings its prey EXACTLY and UNERRINGLY in EACH of the nervous centres.
The result is that the caterpillar is paralyzed, but not immediately
killed, the advantage of this being that the larva cannot be injured by
any movement of the caterpillar, upon which the egg is dep