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Darwin’s Use of Natural Selection, and Metaphors in Science

From its initial publication on November 24th, 1859, Charles Darwin’s On the Origin of Species revolutionized the scientific field through its presentation of evolutionary theory as the biological process capable of accounting for the diversity of life observed in the world.  And the key means by which Darwin proposed evolution to be possible was a mechanism he called natural selection.

From the start, controversy arose against Darwin’s strictly naturalistic explanation for the emergence of new species, and opposition formed swiftly to denounce evolution by natural selection as an insufficient theory that is unscientific in its analysis.  Most of the early opposition was religious in nature, but a more legitimate note of dissent came from Darwin’s own colleague Alfred Russel Wallace, who criticized Darwin’s choice of diction in referring to the evolutionary process by the term natural selection as misleading to the general public, because it needlessly implied a selector in the process.  Darwin countered Wallace’s objection by making the case that, for explanatory purposes, natural selection served as a sufficient term as it gives people a descriptive (albeit metaphorical) idea of how the wholly naturalistic phenomenon operates in comparison to the widely familiar practice of artificial selection.

Wallace himself was a proponent of evolution (often referred to as its co-discoverer along with Darwin), and was by no means opposed to the idea of natural selection.  He simply preferred the phrase “survival of the fittest” as a much better alternate to natural selection, arguing:

Natural Selection is, when understood, so necessary and self-evident a principle, that it is a pity it should be in any way obscured; and it therefore seems to me that the free use of “survival of the fittest,” which is a compact and accurate definition of it, would tend much to its being more widely accepted, and prevent it being so much misrepresented and misunderstood.[1]

Wallace thought that among the scientists in the field, who understood their work, the use of natural selection was not an issue, but among those who did not understand evolution and its process, the metaphor would fail to convey Darwin’s true meaning.  Undoubtedly aware of the attacks his and Darwin’s theory was already being subjected to, Wallace must have been worried that confusing people about the function of natural selection with metaphorical language would only serve to move skeptical minds further away from embracing evolutionary theory.

Darwin responded by agreeing that natural selection can be misleading to some, and even decided to incorporate “survival of the fittest” alongside natural selection as a compromise to Wallace in subsequent editions of On the Origin of Species.  But Darwin also commented how through the continued use of natural selection, his intended meaning will become more widespread, and weaken the sort of objections Wallace made.[2]  Despite these concessions on the issue, Darwin remained largely dismissive of Wallace’s concern, even bluntly responding that Wallace overstated the case for the opposition, and implied that certain individuals will misinterpret any term simply because they are too keen on scrutinizing over matters that are trivial to the average person.[2]

Darwin introduced the concept of descent through modification (i.e. evolution) in Chapter I of On the Origin of Species by drawing parallels to the artificial selection observed in animal domestication[3], something most of his readers would have been familiar with at the time.  He does this as a means of easing his audience into his argument in Chapter IV, where he finally makes his case for natural selection.  The confusion Wallace referred to can be argued here by Darwin’s parallel between artificial and natural selection, and his stating how, “this preservations of favourable variations and the rejection of injurious variation, I call Natural Selection,”[4] because it indicates the presence of intelligent oversight (as is the case for artificial selection), when in reality no such implication need be made for the process to function.  Though in his exchange with Wallace, Darwin appeared to be shrugging the matter off as a nonissue, he nevertheless thought it important to both defend his use of natural selection, and clear up any confusion about his intent in later editions of the book:  “It is difficult to avoid personifying the word Nature; but I mean by Nature, only the aggregate action and product of many natural laws, and by laws the sequence of events as ascertained by us. With a little familiarity such superficial objections will be forgotten.”[5]  Thereby reiterating his confidence that by continually familiarizing the public with his true intended meaning for natural selection, the term can be salvaged and the misguided dissent will disappear.

Charles Darwin insisted that metaphorical terms are needed in science for the sake of expressing an idea, and that it is the general descriptive quality that ought to be focused on by readers, not so much the personification of abstract concepts.  For example, when one says that particles are physically attracted to one another, few actual think there is some sort of conscious intimacy taking place between the consciousness-devoid matter.  Same goes with the description that gravity pushes down on a table, in that nobody would claim that the result caused by the force is driven by a self-awareness to hold on to the object.  In the case of natural selection, while in a literal sense a misnomer, it is nevertheless an apt description of the mechanism taking place.

Despite what is often asserted within anti-Darwinian circles, evolution by natural selection is actually not a completely random phenomenon, in that there does occur a mode of selection.  To explain it simply:  Different variants exist among and within different species, exhibiting different traits; some of them will be better adapted to a given environment, thus they will better survive in said environment, leaving more descendants with the same beneficial traits than the less adapted species.  It is blind, unguided, and in the long-run goalless, but also not really random, in that nature itself non-randomly provides the setting in which the various random traits will either flourish or flounder.  Thus, although the selector is an unintelligent and unaware agent, it is a selector nonetheless; a natural selector.  Meaning that Darwin’s use of natural selection as a metaphorical expression to describe the mechanism of evolutionary theory is a fitting one, and an entirely justifiable one.

Natural selection, as a term, is metaphorical only in the broad sense, but very descriptive in light of the proper understanding of the science involved in its function.  Darwin was right to point out that, given enough promotion, a phrase will begin to take on the definition popularly assigned to it even among the most stubborn minds.  Originally, the Big Bang was coined as a dismissive mockery of the theory, and is neither accurate not descriptive, but it has such wide use that objections have been thoroughly forgotten, and nobody emphasizes its metaphorical implications.  This leads into the main point, and it is one that Darwin himself indirectly made to Wallace, how for those who are opposed to the implications of evolution no term or explanation will be justifiable, and misconstruing natural selection is a means by which to either conform the concept to their personal liking or discredit it as insufficient.  The same would happen with “survival of the fittest,” or any other alternative phrase that could be proposed.  And it is through the merit of its work that science is judged, not by its ability to accommodate to the ignorance of its detractors.

 

[1] Francis Darwin and A. C. Seward, eds., More Letters of Charles Darwin:  A record of his work in a series of hitherto unpublished letters (London: John Murray, 1903. Vol. 1.), 270.

[2] Francis Darwin and A. C. Seward, eds., More Letters of Charles Darwin:  A record of his work in a series of hitherto unpublished letters (London: John Murray, 1903. Vol. 1), 272.

[3] Darwin, Charles. The Origin of Species ed. James Secord (Oxford: University Press, 2008), 111.

[4] Darwin, Origin of Species, 141.

[5] Darwin, Charles. The Origin of Species, 6th edition (London: John Murray, 1872), 63.

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Nietzsche’s Great Blunder on Human Inheritance

Friedrich Nietzsche wrote extensively about his interpretation of human development (as well as human degradation), and in his beautifully articulated fervor he often fell into the habit of overextending his narrow understanding of evolutionary theory.

One cannot erase from the soul of human being what his ancestors like most to do and did most constantly / It is simply not possible that a human being should not have the qualities and preferences of his parents and ancestors in his body, whatever appearances may suggest to the contrary (Beyond Good and Evil, “What is Noble,” Section 264).

The detrimental part of Nietzsche’s error above is his apparent endorsement of Lamarckian inheritance (an early evolutionary hypothesis that states how organisms can pass on traits they acquired in their lifetimes to their offspring; considered to have been largely displaced as a scientifically viable theory in favor of Darwinian natural selection).  In the same section, Nietzsche goes on to say that if one knows about the character traits and likes of the parents, an accurate inference about the child’s personality traits and likes also becomes possible; emphasizing that it is only, “with the aid of the best education that one will at best deceive with regard to such a heredity.”  Nevertheless, Nietzsche ignores the impact that environmental pressure plays on the development of a child’s psychology, i.e. the fact that people (in particular children) seem to readily adopt the characteristics and traits that are prevalent in their surroundings (this is not an absolute rule, but a general statement).

For example, I have always lived in working-class urban areas in the United States, where there reside quite a few immigrant households (my own included).  And where there are immigrant households in the U.S., there are also first-generation Americans.  By Nietzsche’s assessment these first-generationers should retain the “qualities and preferences” of their parents and ancestors, yet in reality, more often than not, they simply don’t.

If they were born here–or arrived here at a young age–went to American schools, associated with American peers, and indulged in American pop culture to any extend, their qualities and preferences will be inseparable from that of anyone else whose ancestry goes back several generations in this country.  This will be true in regard to their most basic characteristics, such as their accents, their mannerisms, their values, their ideals, their politics, and their interaction with societal phenomena.  What remains of the traditional ties to the parent’s mindset becomes solely a sentimental practice for the sake of the still unassimilated elders, rather than a reflection of sincere attachment to ancestral values.

Nietzsche might have countered by saying that this is just part of the deceptive education he warned about.  But if we accept that people can be deceived about their likes and preferences by their surroundings, does it not also warrant the notion that people are deceived about their likes and preferences by their parents (i.e. childhood indoctrination), rather than having inherited them by Lamarckian means?  In fact, under close scrutiny Nietzsche’s two opposing premises seem to be virtually identical, as long as one does away with the Lamarckian inheritance component in the first.

Nietzsche rejected free will as a viable factor in human psychology.  Thus he may have been motivated to accept acquired inheritance as a necessity to explain human behavioral traits in a completely deterministic universe.  But, if so, this is a needless exercise on his part, since the fact that people’s behaviors are determined by a combination of genetic (in a purely biological sense, not the abstract personal interests discussed above) and environmental factors, is sufficient enough in offering a thorough explanation of the matter.  However, I doubt that free will held any real motivation in Nietzsche’s reasoning on the subject.

More likely, Nietzsche saw Lamarckian inheritance as a more fitting addition to his greater philosophical aims.  Charles Darwin had adamantly proposed that in the grand scheme of things, the only coherent way to speak of evolution is on the level of populations, not individuals.  To Nietzsche–who by all accounts had no trouble accepting either Darwin’s theory by natural selection, or the common descent of living organism–this view would have been too naive to satisfy his want for a more inwardly self-reflection (he was after all more a philosopher, than a scientist), not to mention I suspect he probably saw it as antithetical to his own promotion of individual development and preservation, in favor to the preservation of the population as a whole.

Thus, it might be safe to say, that in this case at least, Nietzsche had fallen into the same trap he had warned others of with so much rational eloquence.  He overlooked the fact that the veracity of a conclusion cannot be determined by its conformity to our preferences, but must stand on its own merits.