instinct. There is no intelligence in
which some traces of instinct are not to be discovered, more especially
no instinct that is not surrounded with a fringe of intelligence. It is
this fringe of intelligence that has been the cause of so many
misunderstandings. From the fact that instinct is always more or less
intelligent, it has been concluded that instinct and intelligence are
things of the same kind, that there is only a difference of complexity
or perfection between them, and, above all, that one of the two is
expressible in terms of the other. In reality, they accompany each other
only because they are complementary, and they are complementary only
because they are different, what is instinctive in instinct being
opposite to what is intelligent in intelligence.

We are bound to dwell on this point. It is one of the utmost importance.

Let us say at the outset that the distinctions we are going to make will
be too sharply drawn, just because we wish to define in instinct what is
instinctive, and in intelligence what is intelligent, whereas all
concrete instinct is mingled with intelligence, as all real intelligence
is penetrated by instinct. Moreover, neither intelligence nor instinct
lends itself to rigid definition: they are tendencies, and not things.
Also, it must not be forgotten that in the present chapter we are
considering intelligence and instinct as going out of life which
deposits them along its course. Now the life manifested by an organism
is, in our view, a certain effort to obtain certain things from the
material world. No wonder, therefore, if it is the diversity of this
effort that strikes us in instinct and intelligence, and if we see in
these two modes of psychical activity, above all else, two different
methods of action on inert matter. This rather narrow view of them has
the advantage of giving us an objective means of distinguishing them. In
return, however, it gives us, of intelligence in general and of instinct
in general, only the mean position above and below which both constantly
oscillate. For that reason the reader must expect to see in what follows
only a diagrammatic drawing, in which the respective outlines of
intelligence and instinct are sharper than they should be, and in which
the shading-off which comes from the indecision of each and from their
reciprocal encroachment on one another is neglected. In a matter so
obscure, we cannot strive too hard for clearness. It will always