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Show 430 CONCLUDING REMARKS. CIIAP. XXVIII. most distinct genera and orders within the same great class,for instance, whales, mice, birds, and fishes-are all t~e descendants of one common progenitor, and we must aJmit th~t the whole vast amount of difference between these forms of hfe has primarily an·s en from s1· mp 1e van·a b 1'l 1't Y · To con. sider the sub-ject under this point of view is enough to stnke one dumb with amazement. But our amazement ought to be lesse~ed when we reflect that beings, almost infinite in number~ durmg an almost infinite lapse of time, have ofte~ had thmr whole organisation rendered in some deg~·ee plas~IC, and that each sbght modification of structure whJCh_ ~as m an_y wa~ beneficial under excessively complex cond1t10~s of hfe, ~1l~ ~ave been preserved, whilst each which was m any way lllJ~rwus will have been rigorously destroyed. An_d t~e lo~g-contmued accumulation of beneficial variations w1ll mfalhbly lead to structures as diversified, as beautifully adapted for various purposes, and as excellently co-ordinated, as we see in the animals and plants all around us. Hence I have spoken of selection as the paramount power, whether applied by man to the formation of domestic breeds, or by nature to the production of species. I may recur to the metaphor given in a former chapter: if an architect were to rear a noble and commodious edifice, without the use of cut stone, by selecting from the frao-ments at the base of a precipice wedge-formed stones for 0 his arches, elongated stones for his lintels, and flat stones for his roof, we should admire his skill and regard him as the paramount power. Now, the fragments of stone, though indispensable to the architect, bear to the edifice built by him the same relation which the fluctuating variations of each organic being bear to the varied and admirable structures ultimately acquired by its modified descendants. Some authors have declared that natural selection explains nothing, unless the precise cause of each slight individual difference be made clear. Now, if it were explained to a savage utterly ignorant of the art of building, how the edifice had been raised stone upon stone, and why wedge-formed fragments were used for the arches, flat stones for the roof, &c. ; ·and if the use of each part and of the whole building were pointed out, it would be unreasonable if he declared that nothing had been CnAP. XXVIII. CONCLUDING REMARKS. 431 made clear to him, because the precise cause of the shape of each fragment could not be given. But this is a nearly parallel case with the objection that selection explains nothing, because we know not the cause of each individual difference in the structure of each being. The shape of the fragments of stone at the base of our precipice may be called accidental, but this is not strictly correct; for the shape of each depends on a long sequence of events, all obeying natural laws; on the nature of the rock, on the lines of deposition or cleavage, on the form of the mountain which depends on its upheaval and subsequent denudation, and lastly · on the storm or earthquake which threw down the fragments. But in regard to the use to which the fragments may be put, their shape may be strictly said to be accidental. And here we are led to face a great difficulty, in alluding to which I am aware that I am travelling beyond my proper province. An omniscient Creator must have foreseen every consequence which results from the laws imposed by Him. But can it be reasonably maintained that the Creator intentionally ordered, if we use the words in any ordinary sense, that certain fragments of rock should assume certain shapes so that the builder might erect his edifice? If the various laws which have determined the shape of each fragment were not predetermined for the builder's sake, can it with any greater probability be maintained that He specially ordained for the sake of the breeder each of the innumerable variations in our domestic animals and plants ;many of these variations being of no service to man, and not beneficial, far more often injurious, to the creatures themselves? Did He ordain that the Grop and tail-feathers of the pigeon should vary in order that the fancier might make his grotesque pouter and fantail breeds ? Did He cause the frame and mental qualities of the dog to vary in order that a breed might be formed of indomitable ferocity, with jaws fitted to pin down the bull for man's brutal sport? But if we give up the principle in one case,-if we do not admit that the variations of the primeval dog ~ere intentionally guided in order that the greyhound, for mstance, that perfect image of symmetry and vigour, mig~t be formed,-no shadow of reason can be assigned for the behef that variations, alike in nature and the result |
