Is Evolution Progress?
It is difficult for people today to realize that the idea of progress is an extremely young idea. Of course a few of the ancients had a word to say for progress—a few of the Greeks, for instance. But the idea never really caught on among the masses of men until about two hundred years ago, as J. B. Bury has shown in his history, The Idea of Progress.
During most of man’s existence, a properly conducted public-opinion poll would have shown that, almost without exception, men interpreted human history—both past and to come—in terms either of a Golden Age concept, or in cyclical terms. The Golden Age concept takes various forms, among them the Garden of Eden story. Details vary, but the sense is always the same: Things were once wonderful, but look at the mess we’re in now. Such an interpretation is natural to old age, and can always be supported by facts, if they are properly biased and selected. An equally plausible interpretation, also supportable by carefully chosen facts, is the cyclical theory of history: Things are always getting either better or worse, but there’s never any real change or genuine direction to history…
In contrast to these interpretations, the idea of progress asserts that there is, in some sense, a progressive improvement in man’s life. Not at all times, but viewed over a long period of time. Not at all places simultaneously, but ultimately everywhere. The idea must not be stated with the precision of a mathematical theorem, for it is not such; it is primarily a feeling that governs a man’s view of the world and motivates his actions. The feeling has been immensely important in the development of the Western world during the last two hundred years, and now is becoming explosively effective in the Eastern…
Judged by his actions, Western man now worships the great god Progress more faithfully than ever he did Jehovah. In this religious conversion… human history made sense. [And] perhaps natural history did, too. Was not the succession of forms revealed in the rocks evidence of a progression from lower to higher forms of life? Perhaps to be descended from an ape was a repulsive thought; but why not say instead that we have ascended from—well, why not say from an innocuous amoeba, without mentioning any closer cousins? “From amoeba to man” became a catchword after Darwin. Upward! Progress! Evolution! Even today, “the common man,” in so far as he accepts evolution, probably does so because the theory rides on the coattails of that most popular of all gods, Progress.
But is evolution progress? The philosopher, Bertrand Russell, has wryly remarked, “A process which led from amoeba to man appeared to the philosophers to be obviously progress—though whether the amoeba would agree with this opinion is not known.”
Biologists
have been by no means agreed in their opinions. The issues are complex…
Darwinian adaptation is not in its essence a progressive change,
but merely a dynamic way of preserving the status quo… We conceive
of an initial cybernetic system [a population of animals, for example]
as being subjected to a strain. As the result [there is] an environmental
redefinition of “fittest.” (The mean temperature may drop,
thus favouring larger organisms than formerly.) Under the new definition,
the whole [population shifts], as it were, to a new position—at
which dynamic stability will be maintained. [The previous norm is
replaced by a new one] until the next redefinition of “fittest,”
i.e., the next change in the environment…
[This is an] attempt to depict what we call “secular change,” that is, a drift in the state of the world that is not merely part of a temporary fluctuation… We must remind ourselves of the dangers of implying direction… [What these shifts] represent, really, is change not direction to change…
Man himself has, unwittingly and unwillingly, brought about some well-authenticated cases of evolution in a small way by altering the meaning of “fittest” for some of his pests. In California, scale insects attacking citrus trees were for many years successfully controlled by cyanide fumigation. In three different species, at different times and places, insects have been found which could no longer be killed in this way. In each instance, there must have been present, at the time fumigation began, several mutant forms that just happened to be resistant to cyanide. The mutants survived fumigation and bred a new generation that was more resistant than the initial one. Successive fumigations continued the selection process. With the passing of the years, the resistant forms spread out from each centre of origin, displacing the “normal” types. For the insects, cyanide had become a new aspect of “natural selection.”…
Another instance of the same phenomenon is that of penicillin-resistant strains of disease-causing microbes, which constantly threaten to replace the “normal” strains, as the antibiotic continues to be used…
What about the relevance of these phenomena to the concept of progress? Would we say that each of the changes described is an example of “progress”? Our first impulse may be to say, Not from man’s point of view—since the change makes the human situation more difficult. This, however, is a relatively trivial point. Is the change progressive from the point of view of the pest? It is tempting to say, Yes—to say that the pest, in response to the threat of a new selecting agent, develops a new and superior form.
But it is important to note that the new form is superior only in the new environment. If it is set in competition with the old form in an environment that is lacking the special selecting agent, the resistant strain is speedily displaced by the nonresistant strain through a process of natural selection. In other words, the resistant strain is not a kind of Superpest that possesses some sort of generalized superiority; it is merely a variant that has developed a specialized resistance to a particular agent, for which development it has had to pay a price (in some sense) in the loss of other elements of vigour. Is this progress?
It does not seem quite like what we have in mind when we use the word. With each pest we have two possible cybernetic systems, each one with a different norm-element. Is one norm “higher” than the other? Only if it is, will we be willing to say that the shift from one cybernetic level to another is a form of progress.
By far the greater part of the evolutionary process consists of small steps of the sort discussed, in which the shift from one cybernetic system to another cannot usefully be said to involve direction at all. Over a long period of time, the shift may (for the most part) be in the same sense—but must we speak of this as direction? The horse of today has evolved from a four-toed ancestor about the size of a dog. The evolution involved the proliferation of many forms now extinct, and frequent reversals in “direction,” i.e., from larger to smaller. But even if we ignore the extinctions and the reversals, should we say that horses have evolved “progressively” “upward” from the little Eohippus of thirty million years ago to the big, modern Equus? Surely we are not to succumb to the superstition of our time that holds that bigness is, per se, superior to little-ness? And if we do not make this error, how can we say that the evolution from Eohippus to Equus was a progress? The former undoubtedly enjoyed as good a cybernetic equilibrium with its environment as the latter.
Even those who are not tempted to equate Bigger with Better are likely to succumb to another temptation: to think of parasites as immoral, and the evolution from the free-living state to a condition of dependence as being somehow a “downward” evolution, a “degenerative” or “retrogressive” evolution. “Degenerative” it certainly is, if one means by this no more than that unneeded organs wither away in the process—but is this bad? What virtue would there be in a tapeworm’s having eyespots, living as it does in the perpetual darkness of the mammalian gut? Is extravagance a virtue? And as for “retrogressive,”—well, a tapeworm is like nothing on its family tree. It has not gone backward to become an earlier species; it has gone forward (if we must use direction words) to develop new adaptations to its particular situation. Not any old worm can be a successful parasite; it takes special gifts.
So we see that the concept of progress, for all its historical importance in sheltering the idea of evolution, is not easily applicable to facts of biology. There may be a sense in which it is useful to say that progress has occurred; but we have not yet discovered it. Perhaps we will later. For the present, it is best to agree that neither adaptation alone, nor adaptation coupled with secular change, necessarily constitute progress.