134 THE GROUNDWORK OF SCIENCE

structure. They may thus be said to be sensuous reflex

actions, not of this or that organ, but of each animal as a

whole, and so instinct may be explained as a form of reflex

action in the highest and widest sense of that term. But it

must not be forgotten that the actions which instinct prompts

are not absolutely invariable. They are modifiable to a

certain extent by circumstances, through such powers of per-

ception as different animals may possess. The absence of

accustomed objects and the presence of others in their place,

may lead birds in abnormal conditions to build their nests in

unwonted ways. Similarly, many creatures may be led, by

the pressure of adverse circumstances, to seek their food in

ways different from those which beings of their species usually

employ. In this we seem to see the action of a cognitive

power of some sort co-operating with and modifying the

promptings of instinct. But however much it may now and

again be modified, it is clear (from the facts to be noted as to

human infancy, the earliest stages of existence in individual

beasts and birds, and, above all, from the instinctive activities

of insects) that there are courses of continuous action to

which animals are prompted by an internal spontaneous

impulse, which impulse is blind as to the beneficial conse-

quences of the actions it induces.

Instinct, then, would seem to be a special internal tendency

to blindly perform a series of definite and useful actions.

It cannot be insentient reflex action, neither can it be

what we have termed the sensuous reflex action of an

organ or system of organs. It must be more : it must be

the sensuous reflex action proper to an individual animal

as one whole, or as we before said, the highest and most

complex kind of all reflex action, " the reflex action of the

individual."

The facts and considerations brought forward in the present

chapter, not only show us that various material conditions

structure. They may thus be said to be sensuous reflex

actions, not of this or that organ, but of each animal as a

whole, and so instinct may be explained as a form of reflex

action in the highest and widest sense of that term. But it

must not be forgotten that the actions which instinct prompts

are not absolutely invariable. They are modifiable to a

certain extent by circumstances, through such powers of per-

ception as different animals may possess. The absence of

accustomed objects and the presence of others in their place,

may lead birds in abnormal conditions to build their nests in

unwonted ways. Similarly, many creatures may be led, by

the pressure of adverse circumstances, to seek their food in

ways different from those which beings of their species usually

employ. In this we seem to see the action of a cognitive

power of some sort co-operating with and modifying the

promptings of instinct. But however much it may now and

again be modified, it is clear (from the facts to be noted as to

human infancy, the earliest stages of existence in individual

beasts and birds, and, above all, from the instinctive activities

of insects) that there are courses of continuous action to

which animals are prompted by an internal spontaneous

impulse, which impulse is blind as to the beneficial conse-

quences of the actions it induces.

Instinct, then, would seem to be a special internal tendency

to blindly perform a series of definite and useful actions.

It cannot be insentient reflex action, neither can it be

what we have termed the sensuous reflex action of an

organ or system of organs. It must be more : it must be

the sensuous reflex action proper to an individual animal

as one whole, or as we before said, the highest and most

complex kind of all reflex action, " the reflex action of the

individual."

The facts and considerations brought forward in the present

chapter, not only show us that various material conditions