we can perceive why matrimony, as we practise it, should result in
increasing the personality of our race: for the reason namely that
psychical similarity determines the selection. At first sight,
indeed, such a natural affinity would seem to have little or nothing
to do with marriage. As far as outsiders are capable of judging,
unlikes appear to fancy one another quite as gratuitously as do
likes. Connubial couples are often anything but twin souls. Yet our
own dual use of the word "like" bears historic witness to the
contrary. For in this expression we have a record from early Gothic
times that men liked others for being like themselves. Since then,
our feelings have not changed materially, although our mode of
showing them is slightly less intense. In those simple days
stranger and enemy were synonymous terms, and their objects were
received in a corresponding spirit. In our present refined
civilization we hurl epithets instead of spears, and content
ourselves with branding as heterodox the opinions of another which
do not happen to coincide with our own. The instinct of
self-development naturally begets this self-sided view. We
insensibly find those persons congenial whose ideas resemble ours,
and gravitate to them, as leaves on a pond do to one another, nearer
and nearer till they touch. Is it likely, then, that in the most
important case of all the rule should suddenly cease to hold? Is it
to be presumed that even Socrates chose Xantippe for her remarkable
contrariety to himself?

Mere physical attraction is another matter. Corporeally considered,
men not infrequently fall in love with their opposites, the
phenomenally tall with the painfully short, the unnecessarily stout
with the distressingly slender. But even such inartistic
juxtapositions are much less common than we are apt at times to