THE IMPLICATIONS OF NATURAL SELECTION
(1) In the first place, note that, according to this theory, there can be no stable type; there can be no fixity of species. All is in flux. Environment is never exactly the same, even for two days at a time, let alone for two successive thousand years. Very long slow changes in climate, or any other factor of environment, would necessarily involve long, unceasing, slight transformation, never halting. The theory necessarily demands a living world in a state of slow but incessant transformation, with no fixed mature results at the end of development.
It is only by the loosest sort of thinking, and by substituting imagination for close reasoning, that the ideas of Natural Selection and permanent stable types can be reconciled.
Thus some have said that the Seal was “sifted out” by Natural Selection, got more and more suited to its habitat by “survival of the fittest,” until it had no further need for adaptation: it was at last perfectly adapted to the purposes of its life.
Well, one of the most pressing needs of the seal under the conditions of its life is to scramble on to the icefloes in order to escape from its most deadly enemy. It does so most clumsily and ineffectually by the help of its flappers. For countless generations Natural Selection has had time to work if it were capable of bettering that state of affairs by producing flappers more serviceable. It has not done so. Why? Not because the seal is “in equilibrium,” but because, however it may have evolved, it is now a fixed type: mature: it is what is and can now no longer change its fundamental structure.
It is true that Darwin and others talk vaguely of the process “reaching equilibrium,” but that, according to his own theory, is a contradiction in terms. Under Natural Selection there can be none such.
Darwin, Wallace, and the rest did not think clearly enough to see that this was so, but so it is. If a hare runs fast because it has developed its speed through an immense series of faster and faster hares who “survived” because their speed made them “fitter” to escape enemies, then the process demands that the speed shall continually increase. Your hare of 1925 that can cover the measured mile in three and a half must develop into your hare of A.D. 20,000 who can cover it in three: for there is no doubt whatsoever that an increase of speed has survival value. And he must be developing all the time. There is no escape from that conclusion, if the theory of Natural Selection held water: which it doesn’t.
That is the first necessary result of Natural Selection. If the theory of Natural Selection is true there are not now, and cannot have been in the past, fixed types recognizable by marked and permanent characters.
(2) Next, observe that the theory of Natural Selection also demands a regular progression, and a very slow one. It involves, for instance, the development of a land animal out of a water animal by an immense accumulation of exceedingly slight differences in each generation, favourable to a water animal’s longer and longer bouts of staying out of water. These exceedingly slight differences in each generation are presupposed to be only such as we always observe between parent and child. Darwinian Natural Selection as a prime cause can admit no rapid, startling changes.
For it presupposes a purely blind, unintentional, “sieve-like” action, not merely as killing off the unfit—which is obvious—but as producing gradually increasing fitness, with no inherent power in the organism for adaptation. According to Darwinian Natural Selection, what works the change is a vast number of successive tiny differences such as always appear between parent and progeny.
To turn out, for instance, the white bear of the Arctic from the general undifferentiated type of subfusc beardom you must have hardly perceptible steps beginning with the slightly lighter hue of a few bears, and proceeding gradually for æons and æons until only the pure white survived (though however one could get at pure white by such a process it would have puzzled them to say!)
Natural Selection, then, imperatively demands for each species a slow ascension, a regular, inclined plane, produced over a prodigious space of time, in which the animal is getting whiter and whiter, or fleeter and fleeter, or what not, by infinitesimal degrees.
The theory of Natural Selection necessitates the presence, in all fossils, and even during any considerable historical period, of increasing progressive slight differences in type.
It is no good saying that Natural Selection might apply to new highly suitable variations coming at exactly the right moment to benefit the animal. Such variations indicate Design of some sort and Will. If the climate gets colder and very woolly types of an animal immediately begin to appear, that is not Natural Selection; that is a startling but obvious adaptation, due to some other cause, of organism to environment. It is the very negation of a blind, causeless, undefined, unwilled process which the theory of Natural Selection was intended to bolster up.
(3) Again, Natural Selection implies advance by the killing off of the organism not possessed of a specific advantage. How is it then that organisms not possessed of the advantage survive—as they certainly do—side by side with the advantaged and in the same environment? The Elephant’s trunk grew longer because the short-trunkites were killed off. What of the Tapir?
(4) Again, Natural Selection cannot allow itself to be ousted by any rival aid to development.
This is a very important point. The whole point of Natural Selection as the explanation of the difference between living beings is that it is mechanical. The moment you have to prop it up by saying “Animals with similar variations will tend to mate one with the other,” or “Striking change in environment will tend to produce corresponding variations,” you are abandoning Natural Selection, and covering up your retreat with mere verbiage. Why “tend”?
The theory of Natural Selection is a jealous god and it will admit no rival, nor even any support. You must make it your mainstay or give it up: for the whole point of it is that it permits you, if you will, to eliminate Will and Mind from the Universe. The moment you have to prop it up with some theory involving Will and Mind the essence of it disappears. Therefore does Weissmann, the most famous of its later defenders, ascribe to it “All-might” (to make a barbaric translation of his term) and desperately add that we “must” accept Natural Selection because the only alternative is design—that is God; the Inadmissible: the Dogmatically Denied.
Suppose a man to say, “No one threw that stone: it hit my window by the force of gravity.” Another then points out that a stone, merely falling, would have gone past the window, and that the stone, from the course it took, striking the window, must have been thrown by someone to take the glass at the angle it did. To this the man replies: “Well, yes, perhaps; but gravity influenced its course.” Clearly he has abandoned his case. He was arguing that the stone merely fell: that no Will or Design caused it to take the path it did. When he admits a thrower of the stone and merely brings in gravity as affecting the course of the stone he abandons his position altogether.
That is exactly parallel to the old-fashioned advocate of Natural Selection who reluctantly admits, on modern evidence—and mainly through the work of De Vries—great and rapid changes adapting animals to a new environment, but adds, “Anyhow, those that don’t change will be killed off.” Of course they will! But that isn’t the point. The point is that the killing off of the unfit is proved not to be the agent of change. The climate gets colder. Much thicker fleeces begin to appear. Such animals as don’t show the new thick fleeces begin to die out. Obviously!—But that doesn’t explain why the thicker fleeces began to appear. If you admit Mutation (the name for rapid change) or Saltatory Evolution (Evolution by jumps) poor old Natural Selection goes by the board.
In the same way Natural Selection does not mean that, upon a change of environment, things unsuitable to the new condition tend to disappear. Of course they do.
If there is a flood, fishes survive, cattle are drowned. The fishes are fitter to survive the flood than the cattle. And if the flood lasted long enough, there would at the end of it be plenty of fish and no cattle. But to talk of that as “Natural Selection” is to use the same word in two different senses.
The theory of Natural Selection as the agent of Evolution does not mean that floods drown cattle and don’t drown fish. We all know that. The theory means that successive floods turn cattle into fish—and that is a very different proposition!
The theory of Natural Selection does not mean that things die out when they cannot live; if it only meant that it would not be worth stating. It means that the chance of survival, through exceedingly small and inevitable slight differences between Parent and offspring, is the great cause producing the marvels in adaption and beauty and special action in a million forms which make up the life of this world. Its chief use has been to back up the denial of God, and now it has broken down the opponents of Design in the Universe must seek for a new reply.
They are still seeking it.
(5) Next note that the theory of Natural Selection implies a continual accumulation of fresh advantages; although for this there is no sort of necessity and, on a theory of blind chance, no possibility of such a thing. It is a mere gratuitous assumption with no reason behind it and all actual experiment against it. This is the point which Morgan (Professor of Experimental Zoology at Columbia University) so powerfully emphasizes in his critique of the Theory of Evolution which came out just after the war.
To apply the theory to that simple case of the animal on the tidal beach. Those with minute advantages over the average in the way of standing slightly longer immersion have survival-value over those who are only on or below the average. But why—by the mere blind selection of death—should the advantage accumulate from generation to generation? Why should new advantageous exceptions, each better than the last, appear in unbroken succession generation after generation?
(6) Lastly, there is the exceedingly important, the essential, point that, according to the theory of Natural Selection, each slight successive change in the whole series must give its possessor a survival-value. Not only must a fully formed flapper be an advantage (to a whale) over a leg, by the time it has become aquatic, but a half-formed flapper must be an advantage to the whale while it still uses the land. Clearly it was nothing of the kind. If transformism be true (which is not certain) then Design explains the leg into a flapper in spite of the intermediate disadvantages. If there is Design behind the transformation, if there is special protection for the heavily handicapped intermediate form, one can understand the possibility of it. Under Natural Selection it is impossible.
So much for the Implications of the Theory. I hope I have put them as clearly as may be, and accurately; not a very hard task, for it was an extremely crude and simple theory during its short life, and could be grasped (and refuted) by anyone.
Let me summarize these Implications.
(1) First, Change must be continual and types must be always in a state of flux. Stability of Type and Natural Selection form a contradiction in terms. You can have one or the other—but you cannot have both.
(2) Second, Natural Selection inevitably implies that, on searching the records of Evolution, we shall find only gradual change, proceeding continually, so that the ascending organisms follow, as it were, regular inclined planes showing no steps. The whole of Evolution should, under Natural Selection, prove to be of this kind. Thus you would have, say, tigers as they are now, gradually developing out of some tiger-like ancestor in the past by a regular and uninterrupted process, never achieving a fixed type but perpetually changing as time went on; and that perpetual change would be still going on to-day. The world about us would not show (as it does) a vast number of strongly separate types but a confused jumble of forms all melting one into the other.
(3) Third, Natural Selection presupposes Evolution through the killing off of individuals lacking certain advantages, how then do other types continue still to be with us in spite of lacking these advantages?
(4) Fourth, Natural Selection must stand or fall of itself. If you try to prop it up with Will or Design, inherent in the organism, or acting in any other fashion, you destroy its whole thesis. If you say, for instance, “the country becoming dryer, animals which adapted themselves to the new conditions survived, and those that could not adapt themselves died out,” that is no example of Natural Selection as an agent of Evolution. For when you say “Animals which adapted themselves to the new conditions,” you are presupposing some inherent power in the animal to adapt itself: you are presupposing a form of Will and Design, and thereby denying the purely mechanical action, the unintelligent “sieve,” of Natural Selection as an agent.
(5) Fifth, Natural Selection presupposes, quite gratuitously, that new survival values will be perpetually and progressively appearing. That sheep woollier than the average of a flock have survival value as the winters get colder is obvious: too obvious to need stating. But why should the next generation, under mere chance, produce a number of new still woollier variations, and the one after that yet another even woollier set; and so on indefinitely?
(6) Sixth, Natural Selection presupposes that in every stage of the slow process of development by infinitesimal differences, each successive difference is more advantageous than the last and has a special survival value.
A bird with fully formed wings has a survival value through being able to fly away from land enemies. But if it evolved from a reptile by Natural Selection, then each stage between the useful Reptilian fore-leg and the useful wing must have had a special advantage over the stage immediately preceding it. There must have been an advantage in the fore-leg getting stumpy, then in its getting stumpier, then its getting so stumpy that the beast couldn’t use it at all. And this must be true of every change in all the millions of tiny evolutionary changes proceeding through æons of time. All the way along, from the first signs of something which later on will be an advantage to the mature type, through myriads of generations, from the first origins when the organ was as yet rudimentary to the last when it was perfected, every step must have had a survival value over the last. And this must apply not only to broad cases, such as the reptile’s fore-leg turning into the bird’s wing, but to every one of innumerable organs and to every part of each organ. Otherwise the theory breaks down.
The implications then of Natural Selection as the blind agent of development, “give one furiously to think.” Merely stated roughly as I have done here, they shake the ordinary man’s confidence in it. But when we come to ordered proofs against it, we shall find those proofs conclusive.
To these I now turn.