In short, my doctrine is simply the old-fashioned and confiding belief
that marriages are made in heaven: with the further corollary that
heaven manages them, one time with another, a great deal better than Sir
George Campbell.

Let us first look how Falling in Love affects the standard of human
efficiency; and then let us consider what would be the probable result
of any definite conscious attempt to substitute for it some more
deliberate external agency.

Falling in Love, as modern biology teaches us to believe, is nothing
more than the latest, highest, and most involved exemplification, in the
human race, of that almost universal selective process which Mr. Darwin
has enabled us to recognise throughout the whole long series of the
animal kingdom. The butterfly that circles and eddies in his aërial
dance around his observant mate is endeavouring to charm her by the
delicacy of his colouring, and to overcome her coyness by the display of
his skill. The peacock that struts about in imperial pride under the
eyes of his attentive hens, is really contributing to the future beauty
and strength of his race by collecting to himself a harem through whom
he hands down to posterity the valuable qualities which have gained the
admiration of his mates in his own person. Mr. Wallace has shown that to
be beautiful is to be efficient; and sexual selection is thus, as it
were, a mere lateral form of natural selection--a survival of the
fittest in the guise of mutual attractiveness and mutual adaptability,
producing on the average a maximum of the best properties of the race in
the resulting offspring. I need not dwell here upon this aspect of the
case, because it is one with which, since the publication of the
'Descent of Man,' all the world has been sufficiently familiar.