Survival of the fittest

Survival of the fittest is a phrase which is a shorthand for a concept relating to competition for survival or predominance. Originally applied by Herbert Spencer in his Principles of Biology of 1864, Spencer drew parallels to his ideas of economics with Charles Darwin's theories of evolution by what Darwin termed natural selection.

The phrase is a metaphor, not a scientific description; and it is not generally used by biologists, who almost exclusively prefer to use the phrase "natural selection".

History of the phrase

While the British economist Herbert Spencer is often credited with introducing the phrase "survival of the fittest" in his 1851 work Social Statics (relating to free market economics) or his First Principles of a New system of Philosophy of 1862, he actually did not use the phrase until after reading Darwin's Origin of Species. and introduced it in his Principles of Biology of 1864, vol. 1, p. 444, writing "This survival of the fittest, which I have here sought to express in mechanical terms, is that which Mr. Darwin has called 'natural selection', or the preservation of favoured races in the struggle for life."

In The Man Versus The State of 1884 Spencer used this phrase to reinforce his social theories, writing "Thus by survival of the fittest, the militant type of society becomes characterized by profound confidence in the governing power, joined with a loyalty causing submission to it in all matters whatever." Companies which offer better goods and services survive better in the marketplace and tend to accumulate an ever-growing market share. Poorly-adapting companies will be forced out by better-adapting ones: "killed" by the competition.

In the first four editions of The Origin of Species, Charles Darwin used the phrase "natural selection" and preferred that phrase. However, Spencer's Principles of Biology drew parallels between his economic theories and Darwin's biological ones and made first use in print of the phrase "survival of the fittest". Darwin agreed with Alfred Russel Wallace that this phrase avoided the troublesome anthropomorphism of "selecting", though it "lost the analogy between nature's selection and the fanciers'." It was used by Darwin in the 5th edition of The Origin published on 10 February 1869, in a secondary header of Chapter 4 about natural selection [http://www.bartleby.com/11/4001.html and at several places in the text, mostly using the phrase "Natural Selection, or the Survival of the Fittest". He gave full credit to Spencer, writing "I have called this principle, by which each slight variation, if useful, is preserved, by the term natural selection, in order to mark its relation to man's power of selection. But the expression often used by Mr. Herbert Spencer, of the Survival of the Fittest, is more accurate, and is sometimes equally convenient." At this time the word "fittest" would have primarily meant "most suitable" or "most appropriate" rather than "in the best physical shape".

In modern times, however, the phrase is widely used in popular literature as a catchphrase for any topic related or analogous to evolution and natural selection. It has thus been applied to principles of unrestrained competition, and it has been used extensively by both proponents and opponents of Social Darwinism. Its shortcomings as a description of Darwinian evolution have also become more apparent (see below).

Evolutionary biologists criticize how the term is used by non-scientists and the connotations that have grown around the term in popular culture. The phrase also does not help in conveying the complex nature of natural selection and modern biologists prefer and almost exclusively use the term natural selection. Indeed, in modern biology, the term fitness measures reproductive success and is not explicit about the specific ways in which organisms can be "fit" as in "having phenotypic characteristics which enhance survival and reproduction" (which was the meaning that Spencer had in mind).

Is "survival of the fittest" a tautology?

The phrase "survival of the fittest" is sometimes claimed to be a tautology (i.e. it is a statement which is true by its own definition, and is therefore intrinsically uninformative). Unfortunately, although in evolutionary biology the word "fitness" has nothing to do with being "fit" since it quantifies potential or realized reproductive success (as in "realized fitness"), the noun's etymological connection with the adjective "fit" leads many to charge the phrase "survival of the fittest" is equivalent to saying "those who survive best are those who survive best" or "those who reproduce most are those who reproduce most", i.e., that it is a tautology. The reasoning is that if we take the word "fit" to mean "fitness" then "survival of the fittest" means "highest fitness of those with highest fitness".

However, Darwin and Spencer used "survival" as a proxy for "fitness" in the modern sense and "fittest" to refer to those individuals that are functionally most capable to tackle life challenges, i.e. to individuals endowed with phenotypic characteristics which improve most strongly one's probability of survival and reproduction. Therefore "survival of the fittest" intends to be a short version of the statement "those who are best at surviving and reproducing will have higher fitness" and this is not a circular statement since the sentence indicates that fitness is the consequence of one's ability to tackle life challenges.

The full cause-and-effect picture of how natural selection generates fitness differences is that those individuals which end up reproducing more do it because they differed from others in biologically relevant traits that affected their probability of surviving and/or reaching reproduction in better condition.

For instance, a gazelle that for some biomechanical reason runs faster than average will be more likely to escape predators and will therefore be more likely to produce more offspring than slower ones since the latter would get to reproduce during fewer breeding seasons. The faster gazelle would therefore be "selected", i.e., it would have higher relative fitness than slower ones, etc, but not "because it is selected" but rather because it can run faster and thus can escape better from predators so that ultimately it will go through more breeding seasons than average gazelles and thus will reproduce more (will have higher fitness).

In the gazelle example, "survival of the fittest" would simply mean that faster gazelles have highest fitness because they are more "fit" at escaping predators. Saying the latter is fully explicit about the causation of fitness differences and is highly informative since this tells us what the selection regime is asking from the gazelles in functional terms.

In the causality chain that leads from functional differences to higher absolute or realized fitness nothing is tautological, since fitness is simply a measurement of the result of selection, a result that is determined by one's biological functionality.

"Survival of the fittest" and morality

Many critics of evolution argue that "survival of the fittest" is a justification for violence and cruelty by premising human "rights" on the perceived quality of an individual by an arbitrary measure of "fitness". Evolution proponents often consider this to be an example of the naturalistic fallacy (or more specifically the is-ought problem), which states that prescriptive, moral statements cannot be derived from purely descriptive premises. On this view, while some have tried to use evolution as a justification for pseudoscientific ideas such as some forms of well known eugenics, these ideas are not actually supported by evolutionary theory.

External links

Tautology links

Darwin's Untimely Burial by Stephen J. Gould
Evolution and Philosophy: A Good Tautology is Hard to Find by John Wilkins, part of the talk.origins archive.
CA500: "Survival of the fittest is a tautology" from the talk.origins index to creationist claims by Mark Ridley.
Is "survival of the fittest" a tautology by Don Lindsay.

Morality link

Origins of the phrase

Evolution | English phrases | Metaphors

Survival of the fittest | Survival of the fittest | Survival of the fittest | Zakon močnejšega | 適者生存