nce. It is, therefore, to this vital sensation of
deep or arrested respiration that the impressiveness of those objects
is immediately due.

_The influence of the passion of love._

Sec. 13. Half-way between vital and social functions, lies the sexual
instinct. If nature had solved the problem of reproduction without
the differentiation of sex, our emotional life would have been
radically different. So profound and, especially in woman, so
pervasive an influence does this function exert, that we should
betray an entirely unreal view of human nature if we did not
inquire into the relations of sex with our aesthetic susceptibility.
We must not expect, however, any great difference between man
and woman in the scope or objects of aesthetic interest: what is
important in emotional life is not which sex an animal has, but that
it has sex at all. For if we consider the difficult problem which
nature had to solve in sexual reproduction, and the nice adjustment
of instinct which it demands, we shall see that the reactions and
susceptibilities which must be implanted in the individual are for
the most part identical in both sexes, as the sexual organization is
itself fundamentally similar in both. Indeed, individuals of various
species and the whole animal kingdom have the same sexual
disposition, although, of course, the particular object destined to
call forth the complete sexual reaction, differs with every species,
and with each sex.

If we were dealing with the philosophy of love, and not with that
of beauty, our problem would be to find out by what machinery
this fundamental susceptibility, common to all animals of both
sexes, is gradually directed to more and more definite objects: first,
to one species and one sex, and ultimately to one individual. It is
not enough that sexual organs should be differentiated: the
connexion must be established between them and the outer senses,
so that the animal may recognize and pursue the proper object.

The case of lifelong fidelity to one mate -- perhaps even to an
unsatisfied and hopeless love -- is the maximum of differentiation,
which even overleaps the utility which gave it a foothold in nature,
and defeats its own object. For the differentiation of the instinct in
respect to sex, age, and species is obviously necessary to its
success as a device for reproduction. While this differentiation is
not complete, -- and it often is not, -- there is a great deal of
groping and was