Darwiniana; Essays and Reviews Pertaining to Darwinism

by Asa Gray

"The evidence of design afforded by the marks of adaptation in works of human competence is null and void in the case of creation itself . . . Nature is full of adaptations; but these are valueless to us as traces of design, unless we know something of the rival adaptations among which an intelligent being might have chosen. To assert that in Nature no such rival adaptations existed, and that in every case the useful function in question could be established by no other instrument but one, is simply to reason in a circle, since it is solely from what we find existing that our notions of possibility and impossibility are drawn. . . . We cannot imagine ourselves in the position of the Creator before his work began, nor examine the materials among which he had to choose, nor count the laws which limited his operations. Here all is dark, and the inference we draw from the seeming perfections of the existing instruments or means is a measure of nothing but our ignorance."

But the question is not about the perfection of these adaptations, or whether others might have been instituted in their place. It is simply whether observed adaptations of intricate sorts, admirably subserving uses, do or do not legitimately suggest to one designing mind that they are the product of some other. If so, no amount of ignorance, or even inconceivability, of the conditions and mode of production could affect the validity of the inference, nor could it be affected by any misunderstanding on our part as to what the particular use or function was; a statement which would have been deemed superfluous, except for the following:

"There is not an organ in our bodies but what has passed, and is still passing, through a series of different and often contradictory interpretations. Our lungs, for instance, were anciently conceived to be a kind of cooling apparatus, a refrigerator; at the close of the last century they were supposed to be a centre of combustion; and nowadays both these theories have been abandoned for a third . . . Have these changes modified in the slightest degree the supposed evidence of design?"

We have not the least idea why they should. So, also, of complicated processes, such as human digestion, being replaced by other and simpler ones in lower animals, or even in certain plants. If "we argue the necessity of every adaptation solely from the fact that it exists," and that "we cannot mutilate it grossly without injury to the function," we do not "announce triumphantly that digestion is impossible in any way but this," etc., but see equal wisdom and no impugnment of design in any number of simpler adaptations accomplishing equivalent purposes in lower animals.

Finally, adaptation and utility being the only marks of design in Nature which we possess, and adaptation only as subservient to usefulness, the Westminster Reviewer shows us how:

"The argument from utility may be equally refuted another way. We found in our discussion of the mark of adaptation that the positive evidence of design afforded by the mechanisms of the human frame was never accompanied by the possibility of negative evidence. We regarded this as a suspicious circumstance, just as the fox, invited to attend the lion in his den, was deterred from his visit by observing that all the foottracks lay in one direction. The same suspicious circumstance warns us now. If positive evidence of design be afforded by the presence of a faculty, negative evidence of design ought to be afforded by the absence of a faculty. This, however, is not the case." [Then follows the account of a butterfly, which, from the wonderful power of the males to find the females at a great distance, is conceived to possess a sixth sense.] "Do we consider the deficiency of this sixth sense in man as the slightest evidence against design? Should we be less apt to infer creative wisdom if we had only four senses instead of five, or three instead of four? No, the case would stand precisely as it does now. We value our senses simply because we have them, and because our conception of life as we desire it is drawn from them. But to reason from such value to the origin of our endowment, to argue that our senses must have been given to us by a deity because we prize them, is evidently to move round and round in a vicious circle.

"The same rejoinder is easily applicable to the argument from beauty, which indeed is only a particular aspect of the argument from utility. It is certainly improbable that a random daubing of colors on a canvas will produce a tolerable painting, even should the experiment be continued for thousands of years. Our conception of beauty being given, it is utterly improbable that chance should select, out of the infinity of combinations which form and color may afford, the precise combination which that conception will approve. But the universe is not posterior to our sense of beauty, but antecedent to it: our sense of beauty grows out of what we see; and hence the conformance of our world to our aesthetical conceptions is evidence, not of the world's origin, but of our own."

We are accustomed to hear design doubted on account of certain failures of provision, waste of resources, or functionless condition of organs; but it is refreshingly new to have the very harmony itself of man with his surroundings, and the completeness of provision for his wants and desires, brought up as a refutation of the validity of the argument for design. It is hard, indeed, if man must be out of harmony with Nature in order to judge anything respecting it, or his relations with it; if he must have experience of chaos before he can predicate anything of order.

But is it true that man has all that he conceives of, or thinks would be useful, and has no "negative evidence of design afforded by the absence of a faculty" to set against the positive evidence afforded by its presence? He notes that he lacks the faculty of flight, sometimes wants it, and in dreams imagines that he has it, yet as thoroughly believes that he was designed not to have it as that he was designed to have the faculties and organs which he possesses. He notes that some animals lack sight, and so, with this negative side of the testimony to the value of vision, he is "apt to infer creative wisdom" both in what he enjoys and in what the lower animal neither needs nor wants. That man does not miss that which he has no conception of, and is by this limitation disqualified from judging rightly of what he can conceive and know, is what the Westminster Reviewer comes to, as follows:

"We value the constitution of our world because we live by it, and because we cannot conceive ourselves as living otherwise. Our conceptions of possibility, of law, of regularity, of logic, are all derived from the same source; and as we are constantly compelled to work with these conceptions, as in our increasing endeavors to better our condition and increase our provision we are constantly compelled to guide ourselves by Nature's regulations, we accustom ourselves to look upon these regularities and conceptions as antecedent to all work, even to a Creator's, and to judge of the origin of Nature as we judge of the origin of inventions and utilities ascribable to man. This explains why the argument of design has enjoyed such universal popularity. But that such popularity is no criterion of the argument's worth, and that, indeed, it is no evidence of anything save of an unhappy weakness in man's mental constitution, is abundantly proved by the explanation itself." Well, the constitution and condition of man being such that he always does infer design in Nature, what stronger presumption could there possibly be of the relevancy of the inference? We do not say of its correctness: that is another thing, and is not the present point. At the last, as has well been said, the whole question resolves itself into one respecting the ultimate veracity of Nature, or of the author of Nature, if there be any.