an instinct a series of reflexes such that when the first is set off, the
remainder are set off in a regularly determinate succession.]

The cat runs after the mouse, runs or shows fight before the dog,
avoids falling from walls and trees, shuns fire and water, etc., not
because he has any notion either of life or death, or of self-preservation.
He has probably attained to no one of these conceptions in
such a way as to react definitely upon it. He acts in each case
separately, and simply because he cannot help it; being so framed that
when that particular running thing called a mouse appears in his
field of vision he _must_ pursue; that when that particular barking and
obstreperous thing called a dog appears there he _must_ retire, if at a
distance, and scratch if close by; that he _must_ withdraw his feet from
water, and his face from flame.[2]

[Footnote 2: James: _Psychology_, vol. II, p. 384.]

Similarly, the baby's reaching for random objects, and
sucking them when seized, its turning its head aside, when it
has had enough food, its crying when alone and hungry, are
not, for the most part, deliberate methods invented by the
infant to maintain its own welfare, but are almost as automatic
as the number of sounds omitted by the cuckoo clock at
midnight.

Why do men always lie down, when they can, on soft beds rather
than on hard floors? Why do they sit round the stove on a cold day?
... Why does the maiden interest the youth so that everything
about her seems more important and significant than anything else
in the world? Nothing more can be said than that these are human
ways, and that every creature _likes_ its own ways, and takes to the
following of them as a matter of course.... Not one man in a billion,
when taking his dinner, thinks of utility. He eats because
the food tastes good, and makes him want more. If you ask him
_why_ he should want to eat more of what tastes like that, instead of
revering you as a philosopher, he will probably laugh at you for a
fool.[1]

[Footnote 1: James: _Psychology_, vol. II, p. 386.]

These inborn tendencies to act vary in complexity from the
withdrawing of a hand from a hot stove or the jerking of the
knee when touched in a particular spot to startlingly involved
trains of action to be found in the behavior of certain of the
lower animals. Bergson cites the case of a species of wasp
which with a skill, unconscious though it be, resembling that
of the expert surgeon,