DARWIN'S THEORY DEFENDED.
Belfast, 16th April, 1860. Bin—As you have published? (in your numbers of 24th ultimo and 7th instant) an attack on Darwin's" Origin of Species," I trust you will not refuse to publish a statement on the other side.
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Let me n the first place protest, in the name of science and of common sense, against bringing scientific theories to any other test than that of evidence. "I think it intensely mischievous" to teach that the in- terests of religion require us to interpret the facts of geology and natural history in one way rather than another : and, I think it "the very opposite of inductive truth," to brand as "unflinching materialism" or by any other disagreeable name, the rigorously logical habit of seeking physical causes for physical effects. It is no more "atheistical" to believe that living beings have come into existence by a process, than to believe as your eontributor no doubt believes, that mountains have been raised by plutonic
- forces. He ascribes the origin of species to "a power above established laws, and yet acting in harmony and conformity with them." On what prin- ciple of sound reasoning can we believe in a supernatural agent thus working in organic nature, when there is demonstrably no such power at work in the inorganic world ? I believe, with Owen, (as quoted in your number of the 24th ultimo,) in "a continuously operative secondary crea- tional law," and with Sir John Herschel, (in a letter to Sir Charles Lyell, published in the appendix to Babbage's Ninth Bridgewater Treatise), that species have originated, by a natural process, as distinguished from a super- natural one. buch a process no more supersedes Divine Intelligence, than the action of machinery supersedes human intelligence : and to say that Darwin substitutes spontaneous variation and natural selection for a Creator, is just as absurd its if it were to be said that the figured fabrics woven by Bonelli's exquisitely ingenious electro-magnetic loom are not the work of man, because they are wrought by steam* and electricity. On this sub- jet, see Baden Powell's essay "on the Philosophy of Creation."
Your contributor appears to think it nearly conclusive against the tran- mutation of one species into another, that no such process has come under our observation. But such merely negative evidence as this would be equally valid against the upheaval of mountain-chains, which we cannot doubt has taken place, though the mountains stood at the dawn of history where they stand now. All geology is conversant with processes whichhave not come under our direct observation.
Your contributor strangely misconceives the question at issue, when he *I do not know that steam power has yet been applied to Bond's loam, but no doubt it will be
asks what has become of the great extinct reptiles ? as if this were a greater difficulty on Darwin'a theory than on any other. Darwin has not given any special answer to this question ; but the fact is, independently of any theory, that the larger reptiles have been superseded by mammals : and "natural selection by means of the preservation of favoured races in the struggle for life" is, I believe, the most probable hypothesis to account for such changes. This part of the theory may be admitted without conceding the transmutation of species.
Your contributor says that all Darwin's facts in proof of the variableness of organisms, are taken from among domestic animals. I have not space to state the reasons for believing that such changes do prove very much about the possibilities of change in wild animals. But Darwin also men- tions, though not with sufficient emphasis, the case of the cowslip ; which is shown, by the existence of intermediate gradations, to be a variety of the primrose; although these two flowers differ in the very important par- ticular of the form of the inflorescence; and although they hybridize with difficulty ; which last, your contributor regards as a proof of difference of species. It is true as a general law that varieties of the same species hy- bridize freely, but distinct species do not ; and this is expressed in Dar- win's theory by saying that there is, in every case, a certain degree of di- vergence' beyond which organisms will not hybridize. Your contributor says that domestic breeds may be produced by cross-breeding, which does not occur in nature ; but this is a misconception ; breeds are sometimes im- proved by cross-breeding, but they owe their separate existence to selection, which is the opposite process; and, whatever we may think of the in- ferences Darwin has drawn from it, his reasoning, to prove that selection must occur in nature, is absolutely unanswerable.
Your contributor speaks of horses being "through some influence of cli- mate, transmuted into tapirs, or buffaloes." To assign such a supposition as a possible inference from Darwin's theory, proves only that he has not read the book with care. Darwin rates the direct effect of climate in producing changes in animal forms, very low • he points to the wonderful degree of unlikeness between the animal populations of Australia, South America, and Africa, in the same latitudes and in similar climate.
Your contributor's allusion to hatching "rats out of the eggs of geese," is a sneer at the most unlucky passage of that unlucky book, the Vestiges of Creation ; but Darwin teaches nothing like this : indeed, a distinguished botanist of my acquaintance, though opposed to the theory, believes that Darwin has greatly underrated the rapidity with which changes may and do take place. Darwin says your contributor, "seems to believe that a white bear, by being confined to the slops floating in the Polar basin, might in time be turned into a whale : that a lemur might be turned into a bat." This is a moat unfair way of representing an author's opinions. The allusion to the bear is this. Darwin mentions that a bear has been seen swimming about, and catching the insects that were floating on the water ; and he infers that, could a bear be thus supported all the year round, an animal might in time be formed, resembling the bear as the manati resembles the land paehy- derma. It is true that the passage on this subject is careless and un- guarded; but there is no want of care in the exposition of the manner in which the bat's wing may have been produced. After pointing out the ex- istence of a gradation between the common squirrels and the flying squirrels, he.supposes that, by a similar series of gradations, now lost, the transition was effected between the common lemurs and the flying lemurs; and, by an- other parallel series, but carried a little farther, so as to make the more per- fect wing of the bat, that remarkable form was developed out of some lost, wingless quadruped.
On the origin of man, I prefer to express myself in the words of Baden Powell :—
"In proportion as man's moral superiority is held to consist in attributes not of a material or corporeal kind or origin, it can signify, little how Ids physical nature can have originated. The same moral superiority may equally belong to him whether originally evolved ont of any form of lower organic life, or out of a clod of earth. All truths relative to man's moral or spiritual nature, in proportion as that nature is held to be of an immaterial kind, must be allowed to be entirely indepen- dent of any theories of the origin of his animal and material existence."
I do not see how any unprejudiced person can read Darwin's masterly chapters on the geographical distribution of organisms, without seeing that his argument is to a great extent cumulative. But the main strength of the transmutation theory is in the facts of morphology, especially in the exist- enc,e of rudimentary organs. Why can the bones of a foot or a hand be traced in the bird's wing ? Why have some serpents rudimentary and use- less legs? and some beetles, rudimentary and useless wings'? 'fo ascribe these to direct acts of creation is, in my opinion, neither more nor less ab- surd, than to believe that rocks were created with fossils in them.
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