INTRODUCTION. 
11 
Again, Addison says ■ 
I look upon instinct as upon the principle of gravitation in 
bodies, which is not to be explained by any knowp qualities 
inherent in the bodies themselves, nor from any laws of me- 
chanism, but as an immediate impression from the first Mover, 
and the Divine energy acting in the creatures. 
This mode of 6 looking upon instinct ’ is merely to 
exclude the subject from the sphere of inquiry, and so to 
abstain from any attempt at definition. 
Innumerable other opinions might be quoted from 
well-known writers, ‘looking upon instinct’ in widely 
different ways ; but as this is not an historical work, I 
shall pass on at once to the manner in which science 
looks upon it, or, at least, the manner in which it will 
always be looked upon throughout the present work. 
Without concerning ourselves with the origin of in- 
stincts, and so without reference to the theory of evolution, 
we have to consider the most conspicuous and distinctive 
features of instinct as it now exists. The most important 
point to observe in the first instance is that instinct 
involves mental operations ; for this is the only point 
that serves to distinguish instinctive action from reflex. 
Reflex action, as already explained, is non-mental neuro- 
muscular adaptation to appropriate stimuli ; but in- 
stinctive action is this and something more ; there is in 
it the element of mind. Such, at least, is instinctive 
action in the sense that I shall always allude to it. I 
am, of course, aware that the limitation which I thus 
impose is one which is ignored, or not recognised, by 
many writers even among psychologists ; but I am per- 
suaded that if we are to have any approach to definiteness 
in the terms which we employ— not to say of clear- 
ness in our ideas concerning the things of which we speak 
—it is most desirable to restrict the word instinct to 
mental as distinguished from non-mental activity. No 
doubt it is often difficult, or even impossible, to decide 
whether or not a given action implies the presence of the 
mind-element — i.e., conscious as distinguished from un- 
conscious adaptation ; but this is altogether a separate 
matter, and has nothing to do with the question of 
