th respect to every detail of colour to be
presented by the males.

Now, without any question, we have here a most powerful array of
objections against the theory of sexual selection. Each of them is ably
developed by Mr. Wallace himself in his work on _Tropical Nature_; and
although I have here space only to state them in the most abbreviated of
possible forms, I think it will be apparent how formidable these
objections appear. Unfortunately the work in which they are mainly
presented was published several years after the second edition of the
_Descent of Man_, so that Mr. Darwin never had a suitable opportunity of
replying. But, if he had had such an opportunity, as far as I can judge
it seems that his reply would have been more or less as follows.

In the first place, Mr. Wallace fails to distinguish between brilliancy
and ornamentation--or between colour as merely "heightened," and as
distinctively decorative. Yet there is obviously the greatest possible
difference between these two things. We may readily enough admit that a
mere heightening of already existing coloration is likely enough--at all
events in many cases--to accompany a general increase of vigour, and
therefore that natural selection, by promoting the latter, may also
incidentally promote the former, in cases where brilliancy is not a
source of danger. But clearly this is a widely different thing from
showing that not only a _general brilliancy of colour_, but also _the
particular disposition of colours_, in the form of ornamental patterns,
can thus be accounted for by natural selection. Indeed, it is expressly
in order to account for the occurrence of such ornamental patterns that
Mr. Darwin constructed his theory of sexual selection; and therefore, by
thus virtually ignoring the only facts which that theory endeavours to
explain, Mr. Wallace is not really criticizing the theory at all. By
representing that the theory has to do only with brilliancy of colour,
as distinguished from disposition of colours, he is going off upon a
false issue which has never really been raised[48]. Look, for example,
at a peacock's tail. No doubt it is sufficiently brilliant; but far more
remarkable than its brilliancy is its elaborate pattern on the one hand,
and its enormous size on the other. There is no conceivable reason why
mere _brilliancy of colour_, as an accidental concomitant of general
vigour, should have run into so extraordinary, so elaborate, and so
beautif