This is a mistake. But to see why requires a long story.
The story starts in 1864 with the publication of Herbert Spencer's Principles of Biology. Spencer was trying to reconcile his theory of evolution by the inheritance of acquired traits with Darwin's theory of evolution by natural selection. Darwin accepted Spencer's Lamarckian theory of evolution--the inheritance of acquired traits. But Darwin's distinctive idea was to emphasize natural selection as the main mechanism of evolution: if certain heritable traits increase or decrease the chances of survival and reproduction in the struggle for life, then those traits that favor survival and reproduction will increase in frequency over generations, and thus organisms will become more adapted to their environments, and over a long period of time the differences between varieties of a species can become so great that the varieties become new species.
Although by 1864 Spencer had accepted Darwin's idea of natural selection, Spencer still insisted that the most complex forms of adaptation would require a Lamarckian process: an organism would adopt new habits in response to a changing environment, and as these habits produced heritable changes in the organism, the organism would become better adapted to its environment. In writing about Darwin's theory of natural selection, Spencer coined the phrase "survival of the fittest," a phrase that Darwin had never used.
By 1864, four editions of Darwin's Origin of Species had been published. Darwin had used the phrase "natural selection" as a metaphorical expression suggesting a likeness to "artificial selection." Just as human breeders of domesticated plants and animals select those heritable traits that they preferred, and thus plants and animals became adapted through selective breeding for human purposes, so nature could select those heritable variations in plants and animals that enhanced the chances for survival and reproduction, and thus organisms would become adapted to their environments through natural selection.
On July 2nd, 1866, Alfred Russel Wallace wrote to Darwin, telling him that many readers of the Origin were confused by his use of the expression "natural selection." By personifying Nature as "selecting" or "preferring" some forms of life, and by comparing natural selection to the selective activity of plant and animal breeders, Darwin was leading many readers to assume that evolution requires direction by an intelligent agent to some purpose, and thus they were misunderstanding Darwin's metaphor as if it were literal. Wallace suggested that Darwin could avoid this confusion by adopting Spencer's term "survival of the fittest" as a substitute for "natural selection."
Three days later, Darwin wrote back to Wallace. Darwin recognized the problem indicated by Wallace, and he promised to start using Spencer's phrase. But he still preferred the term "natural selection" because it could be easily used as a noun governing a verb, and because it emphasized the connection between natural and artificial selection that was important for Darwin's argument.
In 1868, Darwin's book The Variation of Animals and Plants Under Domestication was published, and the phrase "survival of the fittest" was used six times. Then, in the fifth edition of Origin, Darwin inserted this phrase in thirteen places. But instead of deleting "natural selection," as Wallace had recommended, Darwin inserted "survival of the fittest" as a synonymous phrase. So, for example, the title of Chapter 4 of Origin was changed from "Natural Selection" to "Natural Selection; or the Survival of the Fittest." He also added some remarks to explain and defend his use of the term "natural selection."
In the Introduction to Variation, he wrote:
This preservation, during the battle for life, of varieties which possess any advantage in structure, constitution, or instinct, I have called Natural Selection; and Mr. Herbert Spencer has well expressed the same idea by the Survival of the Fittest. The term "natural selection" is in some respects a bad one, as it seems to imply conscious choice; but this will be disregarded after a little familiarity. No one objects to chemists speaking of "elective affinity"; and certainly an acid has no more choice in combining with a base, than the conditions of life have in determining whether or not a new form be selected or preserved. The term is so far a good one as it brings into connection the production of domestic races by man's power of selection, and the natural preservation of varieties and species in a state of nature. For brevity sake I sometimes speak of natural selection as an intelligent power; in the same way as astronomers speak of the attraction of gravity as ruling the movements of the planets, or as agriculturalists speak of man making domestic races by his power of selection. In the one case, as in the other, selection does nothing without variability, and this depends in some manner on the action of the surrounding circumstances on the organism. I have, also, often personified the word Nature; for I have found it difficult to avoid this ambiguity; but I mean by nature only the aggregate action and product of many natural laws,--and by laws only the ascertained sequence of events. (I, 6-7)One sees here a conflict in Darwin's rhetorical style of writing. On the one hand, he tells the reader to disregard his metaphorical personification of Nature as implying "conscious choice" or "intelligent power," because nature should be understood as "only the aggregate action and product of many natural laws." On the other hand, he refuses to give up his personification of Nature, apparently because he senses that this engages the mind of the reader through the poetic imagery of Nature as a person.
The anthropomorphic image of Nature as a woman (Mother Nature?) is often vivid in The Origin of Species. For instance, Darwin writes:
As man can produce and certainly has produced a great result by his methodical and unconscious means of selection, what may not nature effect? Man can act only on external and visible characters: nature cares nothing for appearances, except in so far as they may be useful to any being. She can act on every internal organ, on every shade of constitutional difference, on the whole machinery of life. Man selects only for his own good; Nature only for that of the being which she tends. . . . Can we wonder, then, that nature's productions should be far "truer" in character than man's productions; that they should be infinitely better adapted to the most complex conditions of life, and should plainly bear the stamp of far higher workmanship?
It may be said that natural selection is daily and hourly scrutinizing, throughout the world, every variation, even the slightest; rejecting that which is bad, preserving and adding up all that is good; silently and insenibly working, whenever and wherever opportunity offers, at the improvement of each organic being in relation to its organic and inorganic conditions of life. . . .
Although natural selection can act only through and for the good of each being, yet characters and structures, which we are apt to consider as of very trifling importance, may thus be acted on. . . . (1859, 83-84)This passage comes from the first edition. In the sixth edition, Darwin inserted "metaphorically" after "It may" in the second paragraph. So when Darwin is criticized for personifying Nature as an intelligent designer showing "higher workmanship," he can respond by saying this is only a metaphor that should not be taken literally.
But isn't this a bit disingenuous? He wants to evoke in the reader's mind--perhaps unconsciously--the intuitive sense that nature is governed by a wise and benevolent designer. (Today, some evolutionary theorists would say that this is an evolved tendency of the human mind to project anthropomorphic mental agency onto the cosmos.) But if Darwin is questioned about this, he will answer that we should disregard his metaphorical language and recognize that nature is "only the action and aggregate product of many natural laws."
Darwin depicts natural selection here as preserving the good and rejecting the bad, as acting "for the good of each being." But what's the standard here of good and bad?
In the paragraph immediately preceding the paragraph from Variation quoted above, Darwin speaks of the Struggle for Existence, and he writes: "It has truly been said that all nature is at war; the strongest ultimately prevail, the weakest fail; and we know that myriads of forms have disappeared from the face of the earth." So the strong prevail over the weak? So does this mean that interpreting the "survival of the fittest" as the rule of the stronger is really correct, and thus Darwinism ultimately promotes immoralism or nihilism?
In The Origin of Species, Darwin says nothing about morality. In this book, the "good of each being" seems to be nothing more than being well adapted for survival and reproduction, and in the competition for survival and reproduction, the strong will prevail over the weak. But in The Descent of Man, Darwin offers his evolutionary theory of morality as unique to human beings. The naturally evolved moral sense of human beings allows us to sympathize with the victims of injustice and to feel resentment against those who exploit them.
As I have indicated in some previous posts, Darwin saw how the Europeans exploited native people in South America, Australia, and New Zealand. He could see how the Europeans were using their power to extinguish native peoples, and he could imagine that this illustrated the long evolutionary history of tribal warfare as a factor in human evolution. But he could also condemn this as unjust and try to elicit moral emotions that would motivate moral reform. The best example of this was his opposition to slavery.
Darwin could be a moral realist. As a realist, he could recognize the dark side of evolutionary history in which tribal warfare seemed to mean that "might makes right." But as a moralist, he could condemn unjust violence and exploitation to elicit moral reform so that "right makes might." Unfortunately, the popular understanding of Darwinism often saw Darwin's realism but not his moralism.
Similarly, Spencer was accused of promoting "survival of the fittest" understood as a crude endorsement of selfish greed and immoral power-seeking. In his essay "Mr. Martineau on Evolution," Spencer explained that "survival of the fittest" does not mean "survival of the better" or "survival of the superior." "Survival of the fittest" means the survival of those who are adapted to the conditions of life in which they are placed. This does not mean that they are superior or better in any sense, and certainly not in any moral sense.
The most common mistake in the popular caricature of Spencer is that for him "survival of the fittest" required that no charity should be extended to the poor or the disabled, so that the "unfit" should perish. That this is not true is clear if one reads Spencer's Principles of Ethics, which concludes with 18 chapters on the ethics of altruism, sympathy, and beneficence. He opposed coercive state-enforced charity. But he saw voluntary charity as a moral obligation properly enforced by private and public moral sentiments.
Spencer was more utopian than Darwin in that Spencer foresaw that inevitably the cooperative dispositions of human beings would become so well developed that they would cooperate with one another spontaneously without any need for formal law or government. Human history would find its end in perfect anarchy. Spencer's mistake was not in being a moral nihilist, but in being a moral utopian.
Darwin did not embrace Spencer's utopian anarchism. Actually, Darwin was always a bit ambivalent about Spencer. He saw philosophic genius in Spencer. But he also thought he was inclined to vague, abstract speculation that was not constrained by a careful observation of facts. Darwin's disdain for Spencer comes through most clearly in his correspondence with J. D. Hooker in 1862-1866 and in his Autobiography, where he wrote:
Herbert Spencer's conversation seemed to me very interesting, but I did not like him particularly, and did not feel that I could easily have become intimate with him. I think that he was extremely egotistical. After reading any of his books, I generally feel enthusiastic admiration for his transcendent talents, and have often wondered whether in the distant future he would rank with such great men as Descartes, Leibnitz, etc., about whom, however, I know very little. Nevertheless I am not conscious of having profited in my own work by Spencer's writings. His deductive manner of treating every subject is whole opposed to my frame of mind. His conclusions never convince me: and over and over again I have said to myself, after reading one of his discussions,--"Here would be a fine subject for half-a-dozen years' work." His fundamental generalizations (which have been compared in importance by some persons with Newton's laws!)--which I daresay may be very valuable under a philosophical point of view, are of such a nature that they do not seem to me to be of any strictly scientific use. They partake more of the nature of definitions than of laws of nature. They do not aid one in prediciting what will happen in any particular case. Anyhow they have not been of any use to me. (ed. Nora Barlow, 1959, pp. 108-109)
Darwin's correspondence is conventiently available at the Darwin Correspondence Project.
Robert Richards has written a good short paper on comparing Darwin and Spencer. Unfortunately, Richards is so determined to build up Spencer's reputation that he plays down Darwin's scorn for Spencer.
Some of my posts on related themes can be found here, here, here, here, here, here, and here.