h we are
considering. If the objectors will but understand the term in its
correct philosophical sense--or in the only sense in which it presents
any meaning at all,--they will see that Darwinians are both logically
and historically justified in employing the word "accidental" as the
word which serves most properly to convey the meaning that they
intend--namely, variations due to causes accidental to the struggle for
existence. Similarly, when it is said that variations are "spontaneous,"
or even "fortuitous," nothing further is meant than that we do not know
the causes which lead to them, and that, so far as the principle of
selection is concerned, it is immaterial what these causes may be. Or,
to revert to our former illustration, the various weights of different
kinds of earths are no doubt all due to definite causes; but, in
relation to the selective action of the gold-washer, all the different
weights of whatever kinds of earth he may happen to include in his
washing-apparatus are, _strictly speaking_, accidental. And as at
different washings he meets with different proportions of heavy earths
with light ones, and as these "variations" are immaterial to him, he may
colloquially speak of them as "fortuitous," or due to "chance," even
though he knows that at each washing they must have been determined by
definite causes.

More adequately to deal with this merely formal objection, however,
would involve more logic-chopping than is desirable on the present
occasion. But I have already dealt with it fully elsewhere,--viz. in
_The Contemporary Review_ for June, 1888, to which therefore I may refer
any one who is interested in dialectics of this kind[43].

[43] Within the last few months this objection has been presented
anew by Mr. D. Syme, whose book _On the Modification of Organisms_
exhibits a curious combination of shrewd criticisms with almost
ludicrous misunderstandings. One of the latter it is necessary to
state, because it pervades the quotation which I am about to supply.
He everywhere compares "natural selection" with "the struggle for
existence," uses them as convertible terms, and while absurdly
stating that "Darwin defines natural selection as the struggle for
existence," complains of "the liability of error, both on his own
part and on the part of his readers," which arises from his not
having everywhere adhered to this definition! (p. 8).

"Darwin has put