The Survival of the Fittest?

The Survival of the Fittest?

Herbert Spencer’s phrase “the survival of the fittest” has done a lot of mischief, not only in biology, but also in politics, economics, ethics, history, and education. The phrase is riddled with confusion, ambiguity, and tendentious error. I will indict the phrase, first its use in biology and then in other fields, particularly economics. We can start with some trenchant remarks from Keynes: “The philosophers and the economists told us [in the nineteenth century] that for sundry deep reasons unfettered private enterprise would promote the greatest good of the whole. What could suit the business man better?… Thus the ground was fertile for the doctrine that…state action should be narrowly confined and economic life left, unregulated so far as may be, to the skill and good sense of individual citizens actuated by the admirable motive of trying to get on in the world…  The economists were teaching that wealth, commerce, and machinery were the children of free competition—that free competition built London. But the Darwinians could go one better than that—free competition had built man. The human eye was no longer the demonstration of design, miraculously contriving all things for the best; it was the supreme achievement of chance, operating under conditions of free competition and laissez-faire. The principle of the survival of the fittest could be regarded as a vast generalization of the Ricardian economics.”[1] Accordingly, Darwinian biology could be touted as the foundation and rationale of individualistic capitalist economics, and hence anti-socialist politics (as well as egoistic ethics). The phrase “the survival of the fittest” was the expression of solid biological science—and hence of the general nature of life on earth. But the phrase was not much scrutinized, falling off the lips as it does—it sounds like common sense made rigorous. So, let’s ask what it means and whether it describes anything actually true in the biological world.

The phrase is evidently intended to express the idea that the “fittest” organisms live longer than the less fit ones: fitness produces longevity. An individual organism will survive longer than other individuals with which it is in competition if it has a higher degree of fitness. But what is fitness? The OED gives us the following for “fit”: “in good health, especially because of regular exercise”. This is the use of “fit” we employ when we say “You are looking very fit” or “Are you keeping fit?”. We may thus paraphrase Spencer’s phrase as “the survival of the healthiest, especially because of regular exercise”. Those animals survive best that are, and keep, fit—that are “in good shape”. So, now we know what the phrase means, pretty much, but is it true? And let us observe that it is intended to exclude other factors that might be thought to lead to survival—such as being designed by God, or well-connected, or of superior breeding, or notably virtuous. Survival depends solely on fitness—on physical good health. If you want to know whether a given organism will survive longer than its rivals, then you need check its physical fitness and nothing else. However, this test is neither necessary nor sufficient for survival, or even its relative probability. Not necessary because not all organisms are fit in the stipulated sense: are plants fit or bacteria or jellyfish? Do they exercise regularly? Do some have stronger muscles than others, or get out of breath less easily? Of course not, so their survival is not a matter of being more fit than other organisms in the customary sense. Here we might appeal to the definition in terms of “good health”—plants etc. can be more or less healthy. But what is the criterion for good health? It had better not be “conduces to survival” on pain of generating a tautology (“organisms survive best by having traits that conduce to survival”). To avoid this kind of trivialization we need to specify what kind of trait is “healthy”—such as muscular strength, or speed, or flexibility. But these are not universal traits of organisms subject to evolution by natural selection. Many organisms are not fit at all if we mean by “fit” what the dictionary says.  But what else could we mean? Isn’t that definition exactly what we have in mind when we hear the phrase “survival of the fittest”, not noticing that it applies only to a subclass of organisms (mainly humans). And what of rich well-connected humans who are sickly and bed-bound but supported into old age by wealth and privilege, while fit strapping youths die in battle at an early age? It all depends on your circumstances, your environment. Physical fitness is surely just one of many factors that contribute to longevity (in favorable circumstances)—what about intelligence, sociability, cunningness, good looks, an optimistic temperament? Individual physical differences are not the only things that affect survival; the mind does too. Mental qualities are not types of fitness yet they have an impact on survival. We need a more inclusive general notion than “fitness” if we are to capture the full range of survival-conducive traits—without falling back into the tautological “anything that contributes to survival”. The truth is that there is no such general notion, which is why “fitness” is so regularly (and uncritically) invoked.

The upshot is that there is no law of biology that specifies what trait an organism must possess in order to survive, or have the probability of its survival raised. The fitness formulation attempts to specify such a trait, but it fails to say anything true (even approximately). There is no law of the form “All organisms must have trait T in order to survive”. There are many traits that can lead to survival (or its opposite) with nothing significant in common, and many kinds of environmental context that affect the efficacy of those traits (being fit and strong won’t help you survive long in a gladiatorial culture, compared to your less pugilistic compatriots). There is no single trait that is correlated lawfully with survival—not fitness and nothing else. The world is too messy and complicated for that. Nor does Darwinian biology require the existence of such a law. Natural selection acts variously and contextually. So, there is no scientific law of biology that that can be invoked by other disciplines in order to confer respectability on their own predilections. Darwinian biology is not a prelude to laissez-faireeconomics and individualistic capitalism. In particular, there is no biological invisible hand that ensures that the laws governing survival necessarily produce the “fittest” future populations. Natural selection does not select for something called “fitness”, i.e., the state of being fit; it does not increase the level of bodily vigor in the organisms it operates on, or some such thing. Human nature, for instance, is not the result of a law that leads inexorably to an increase in something called “fitness”—we are not the fittest of all creatures (many of us are not fit at all). If being fit is thought to be a perfection, there is no law of biology that leads to a more perfect species. There is no “the survival of the X-ist”, where X is some general trait common to all organisms. There is no law of this form leading inevitably to improvement, progress, a more perfect world. So, there is no law of nature we can rely on to do what an intelligent designer is supposed to do. There is no substitute in nature for what God was supposed to ensure. Evolution could lead to a worse world, a less “fit” world. Natural selection just selects; it doesn’t select for some admirable trait like fitness. When the dinosaurs were wiped out it wasn’t because they weren’t fit—that they didn’t take regular exercise or mind their diet. In the biological world, shit happens; it isn’t all a steady accumulation of fitness, viewed as a type of perfection. It isn’t that evolution will inevitably lead to organisms comparable to Olympic athletes. It isn’t that in the end all animals will be incredibly fit (or incredibly smart or sexy or moral). That is all mythology supported by a rickety phrase invented by a chap named Herbert Spencer in the nineteenth century.

Now we must talk about the appropriation of the offending phrase by economists and sundry others. The idea is that entrepreneurs and their products are subject to the same law that Darwin enunciated and Spencer christened: they survive according to their “fitness”. They compete with each other, subject to no outside authority, in the quest to make a better product, and the best man wins. In this they are just following the dictates of nature, engaged in a battle for survival. But that survival will inevitably bring with it a rise in the quality of the world, i.e., better goods and services. The fittest wins, survives into the future, outclassing the opposition. The business man is like a tiger in the wild, ruthless but bent on benefiting the world by being super-fit. Just as Darwinian laws benefit the species (allegedly), so economic laws benefit society as a whole. The trouble is that there is no such biological law, so that we will need to look elsewhere for a defense of laissez-faire economics. I won’t discuss all the problems of laissez-faire economics—I am not an economist and they have been amply discussed by experts[2]—I wish only to point out that biology provides no rationale for such an outlook. The same is true for politics, morality, history, and education. No respectability accrues from any supposed analogy to orthodox biology to certain doctrines in these areas, because the whole idea of the survival of the fittest is shot through with difficulties. There simply is no well-defined notion of fitness applicable to all organisms such that that trait is selected for in the battle for survival. There is just survival and its absence, aided by a large range of traits each suitable for the species that has them. We can certainly say that those organisms survive that are the fittest to survive, but that is a mere tautology and does not include the ordinary notion of fitness; here “fittest” means “cut out for” not “physically fit”. The phrase has survived as long as it has by dint of ambiguity, vagueness, and suggestiveness, not by denoting a well-founded piece of science. It should be retired from civilized discourse.[3]

[1] This is from Keynes’s 1926 essay “The End of Laissez-faire”.

[2] Keynes has a nice discussion in “The End of Laissez-faire”.

[3] It isn’t that markets don’t operate like species, though they don’t; it’s that species don’t operate like species, as conceived by the survival-of-the-fittest trope. This is really a meme not a scientific theory. Nor is survival the essence of the matter; reproduction is. It should be obvious that the contemporary biologist’s notion of fitness, defined in terms of quantity of offspring, has nothing to do with fitness in the vernacular sense invoked by Spencer’s phrase. There is a lot of confusion surrounding biological terminology here.