We may now look a little more closely at the character and
potentialties of our instinctive life: for this life is plainly of the
highest importance to us, since it will either energize or thwart all
the efforts of the rational self. Current psychology, even more plainly
than religion, encourages us to recognize in this powerful instinctive
nature the real source of our conduct, the origin of all those dynamic
personal demands, those impulses to action, which condition the full and
successful life of the natural man. Instincts in the animal and the
natural man are the methods by which the life force takes care of its
own interests, insures its own full development, its unimpeded forward
drive. In so far as we form part of the animal kingdom our own safety,
property, food, dominance, and the reproduction of our own type, are
inevitably the first objects of our instinctive care. Civilized life has
disguised some of these crude demands and the behaviour which is
inspired by them, but their essential character remains unchanged. Love
and hate, fear and wonder, self-assertion and self-abasement, the
gregarious, the acquisitive, the constructive tendencies, are all
expressions of instinctive feeling; and can be traced back to our
simplest animal needs.

But instincts are not fixed tendencies: they are adaptable. This can be
seen clearly in the case of animals whose environment Is artificially
changed. In the dog, for instance, loyalty to the interests of the pack
has become loyalty to his master's household. In man, too, there has
already been obvious modification and sublimation of many instincts.
The hunting impulse begins in the jungle, and may end in the
philosopher's exploration of the Infinite. It is the combative instinct
which drives the reformer headlong against the evils of the world, as it
once drove two cave men at each others' throats. Love, which begins in
the mergence of two cells, ends in the saint's supreme discovery, "Thou