Here is another passage to the same general effect. In alluding to the objection from inutility as advanced by Bronn, Broca, and Nägeli, Mr. Darwin says:--"There is much force in the above objection"; and, after again pointing out the important possibility in any particular cases of hidden or former use, and the action of the laws of growth, he goes on to say,--"In the third place, we have to allow for the direct and definite action of changed conditions of life, and for so-called spontaneous variations, in which the nature of the conditions plays quite a subordinate part[164]." Elsewhere he says,--"It appears that I formerly underrated the frequency and value of these latter forms of variation as leading to permanent modifications of structure _independently of natural selection_[165]." The "forms of variation" to which he here alludes are "variations which seem to us in our ignorance to arise spontaneously"; and it is evident that such variations cannot well "arise" in two or more species of a genus similarly and simultaneously, so as independently to lead "to permanent modifications of structure" in two or more parallel lines. It is further evident that by "spontaneous variations" Darwin alludes to extreme cases of spontaneous departure from the general average of specific characters; and therefore that lesser or more ordinary departures must be of still greater "frequency." [164] _Origin of Species_, p. 171. [165] _Ibid._ p. 421. Again, speaking of the principles of classification, Darwin writes:-- "We care not how trifling a character may be--let it be the mere inflection of the angle of the jaw, the manner in which an insect's wing is folded, whether the skin be covered by hair or feathers--if it prevail throughout many and different species, especially those having very different habits of life, it assumes high value [i.e. for purposes of classification]; for we can account for its presence in so many forms with such _different habits_, only by inheritance from a common parent. We may err in this respect in regard to single points of structure, but when several characters, let them be ever so trifling, concur throughout a large group of beings _having different habits_, we may feel almost sure, on the theory of descent, that these characters have been inherited from a common ancestor; and we know that such aggregated characters have especial value in classification[166]." [166] _Origin of Species_, pp. 372-373. Now it is evident that this argument for the general theory of evolution would be destroyed, if Wallace's assumption of utility of specific characters as universal were to be entertained. And the fact of apparently "trifling" characters occurring throughout a large group of beings "having different habits" is proof that they are really trifling, or without utilitarian significance.