ry need that it satisfies, it creates a new
need; and so, instead of closing, like instinct, the round of action
within which the animal tends to move automatically, it lays open to
activity an unlimited field into which it is driven further and further,
and made more and more free. But this advantage of intelligence over
instinct only appears at a late stage, when intelligence, having raised
construction to a higher degree, proceeds to construct constructive
machinery. At the outset, the advantages and drawbacks of the artificial
instrument and of the natural instrument balance so well that it is hard
to foretell which of the two will secure to the living being the greater
empire over nature.

We may surmise that they began by being implied in each other, that the
original psychical activity included both at once, and that, if we went
far enough back into the past, we should find instincts more nearly
approaching intelligence than those of our insects, intelligence nearer
to instinct than that of our vertebrates, intelligence and instinct
being, in this elementary condition, prisoners of a matter which they
are not yet able to control. If the force immanent in life were an
unlimited force, it might perhaps have developed instinct and
intelligence together, and to any extent, in the same organisms. But
everything seems to indicate that this force is limited, and that it
soon exhausts itself in its very manifestation. It is hard for it to go
far in several directions at once: it must choose. Now, it has the
choice between two modes of acting on the material world: it can either
effect this action _directly_ by creating an _organized_ instrument to
work with; or else it can effect it _indirectly_ through an organism
which, instead of possessing the required instrument naturally, will
itself construct it by fashioning inorganic matter. Hence intelligence
and instinct, which diverge more and more as they develop, but which
never entirely separate from each other. On the one hand, the most
perfect instinct of the insect is accompanied by gleams of intelligence,
if only in the choice of place, time and materials of construction: the
bees, for example, when by exception they build in the open air, invent
new and really intelligent arrangements to adapt themselves to such new
conditions.[63] But, on the other hand, intelligence has even more need
of instinct than instinct has of intelligence; for the power to give
shape to crud