Darwiniana; Essays and Reviews Pertaining to Darwinism

by Asa Gray

Passing from these attempts to undermine the foundation of the doctrine—which we judge to be unsuccessful—we turn to the consideration of those aimed at the superstructure. Evidences of design may be relevant, but not cogent. They may, as Mill thought, preponderate, or the wavering balance may incline the other way. There are two lines of argument: one against the sufficiency, the other against the necessity, of the principle of design. Design has been denied on the ground that it squares with only one part of the facts, and fails to explain others; it may be superseded by showing that all the facts are in the way of being explained without it.

The things which the principle of design does not explain are many and serious. Some are in their nature inexplicable, at least are beyond the power and province of science. Others are of matters which scientific students have to consider, and upon which they may form opinions, more or less well grounded. As to biological science—with which alone we are concerned—it is getting to be generally thought that this principle, as commonly understood, is weighted with much more than it can carry.

This statement will not be thought exaggerated by those most familiar with the facts and the ideas of the age, and accustomed to look them in the face. Design is held to, no doubt, by most, and by a sure instinct; not, however, as always offering an explanation of the facts, but in spite of the failure to do so. The stumbling-blocks are various, and they lie in every path: we can allude only to one or two as specimens.

Adaptation and utility are the marks of design. What, then, are organs not adapted to use marks of? Functionless organs of some sort are the heritage of almost every species. We have ways of seeming to account for them—and of late one which may really account for them—but they are unaccountable on the principle of design. Some, shutting their eyes to the difficulty, deny that we know them to be functionless, and prefer to believe they must have a use because they exist, and are more or less connected with organs which are correlated to obvious use; but only blindfolded persons care to tread the round of so narrow a circle. Of late some such abortive organs in flowers and fruits are found to have a use, though not the use of their kind. But unwavering believers in design should not trust too much to instances of this sort. There is an old adage that, if anything be kept long enough, a use will be found for it. If the following up of this line, when it comes in our way, should bring us round again to a teleological principle, it will not be one which conforms to the prevalent ideas now attacked.

It is commonly said that abortive and useless organs exist for the sake of symmetry, or as parts of a plan. To say this, and stop there, is a fine instance of mere seeming to say something. For, under the principle of design, what is the sense of introducing useless parts into a useful organism, and what shadow of explanation does "symmetry" give? To go further and explain the cause of the symmetry and how abortive organs came to be, is more to the purpose, but it introduces quite another principle than that of design. The difficulty recurs in a somewhat different form when an organ is useful and of exquisite perfection in some species, but functionless in another. An organ, such as an eye, strikes us by its exquisite and, as we may, perfect adaptation and utility in some animal; it is found repeated, still useful but destitute of many of its adaptations, in some animal of lower grade; in some one lower still it is rudimentary and useless. It is asked, If the first was so created for its obvious and actual use, and the second for such use as it has, what was the design of the third? One more case, in which use after all is well subserved, we cite from the article already much quoted from:

"It is well known that certain fishes (Pleuronecta) display the singularity of having both eyes on the same side of their head, one eye being placed a little higher than the other. This arrangement has its utility; for the Pleuronecta, swimming on their side quite near the bottom of the sea, have little occasion for their eyesight except to observe what is going on above them. But the detail to which we would call notice is, that the original position of the eyes is symmetrical in these fishes, and that it is only at a certain point of their development that the anomaly is manifested, one of the eyes passing to the other side of the head. It is almost inconceivable that an intelligent being should have selected such an arrangement; and that, intending the eyes to be used only on one side of the head, he should have placed them originally on different sides."

Then the waste of being is enormous, far beyond the common apprehension. Seeds, eggs, and other germs, are designed to be plants and animals, but not one of a thousand or of a million achieves its destiny. Those that fall into fitting places and in fitting numbers find beneficent provision, and, if they were to wake to consciousness, might argue design from the adaptation of their surroundings to their well-being. But what of the vast majority that perish? As of the light of the sun, sent forth in all directions, only a minute portion is intercepted by the earth or other planets where some of it may be utilized for present or future life, so of potential organisms, or organisms begun, no larger proportion attain the presumed end of their creation.

"Destruction, therefore, is the rule; life is the exception. We notice chiefly the exception—namely, the lucky prize-winner in the lottery— and take but little thought about the losers, who vanish from our field of observation, and whose number it is often impossible to estimate. But, in this question of design, the losers are important witnesses. If the maxim 'audi alteram partem' is applicable anywhere, it is applicable here. We must hear both sides, and the testimony of the seed fallen on good ground must be corrected by the testimony of that which falls by the wayside, or on the rocks. When we find, as we have seen above, that the sowing is a scattering at random, and that, for one being provided for and living, ten thousand perish unprovided for, we must allow that the existing order would be accounted as the worst disorder in any human sphere of action."

It is urged, moreover, that all this and much more applies equally to the past stages of our earth and its immensely long and varied succession of former inhabitants, different from, yet intimately connected with, the present. It is not one specific creation that the question has to deal with—as was thought not very many years ago—but a series of creations through countless ages, and of which the beginning is unknown.

These references touch a few out of many points, and merely allude to some of the difficulties which the unheeding pass by, but which, when brought before the mind, are seen to be stupendous.