|_The Theory of Natural |_The theory of Natural | |Selection according to |Selection according to | |Darwin._ |Wallace._ | | | | |Natural Selection has been |Natural Selection has been | |the main means of |the sole means of | |modification, not excepting |modification, excepting in | |the case of Man. |the case of Man. | | | | |(_a_) Therefore it is a |(_a_) Therefore it is | |question of evidence |antecedently impossible | |whether the Lamarckian |that the Lamarckian factors | |factors have co-operated. |can have co-operated. | | | | |(_b_) Neither all species, |(_b_) Not only all species, | |nor, _a fortiori_, all |but all specific | |specific characters, have |characters, must | |been due to natural |necessarily have been due | |selection. |to natural selection. | | | | |(_c_) Thus the principle of |(_c_) Thus the principle of | |Utility is not of universal |Utility must necessarily be | |application, even where |of universal application, | |species are concerned. |where species are | | |concerned. | | | | |(_d_) Thus, also, the |(_d_) Thus, also, the | |suggestion as to Sexual |suggestion as to Sexual | |Selection, or any other |Selection, or of any other | |supplementary cause of |supplementary cause of | |modification, may be |modification, must be ruled | |entertained; and, as in the |out; and, as in the case of | |case of the Lamarckian |the Lamarckian factors, | |factors, it is a question |their co-operation deemed | |of evidence whether, or how |impossible. | |far, they have co-operated. | | | | | |(_e_) No detriment arises |(_e_) The possibility--and, | |to the theory of natural |_a fortiori_ the | |selection as a theory of |probability--of any | |the origin of species by |supplementary factors | |entertaining the |cannot be entertained | |possibility, or the |without serious detriment | |probability, of |to the theory of natural | |supplementary factors. |selection, as a theory of | | |the origin of species. |