Some Disconnect on Darwinian Evolutionary Theory

By | April 22, 2013

Juan Bernal

The following exchange resulted when a philosophical acquaintance, call him Pablo, asserted that “the Darwinian revolution in biology … only challenged orthodox religious explanations.”  He also objected to a few other statements that I made concerning Darwinian thought.

I offer them as examples of common misunderstandings – especially among some philosophers — of some aspects of Darwinian evolution by natural selection.

Against the claim that Darwin only challenged orthodox religious explanations,  I pointed out that many historians and commentators on Darwin argue the contrary: namely, that Darwin’s work, Origin of the Species,  faced a variety of resistance,  only part of which stemmed from religious doctrine.  Undeniably, Darwin challenged orthodox religious accounts of life on earth (origin and maintenance); and religious doctrine was a big factor in the thinking of most people.  But more importantly to the history of biological science, Darwin’s evolutionary science also challenged prevailing theories and beliefs of secular scientists and other people who did not base their views on religion at all. The idea of fixity of life species was a far broader idea than just something gotten from religious doctrine.

To this Pablo replied that he disagreed and repeated his view that

most of the scientists before Darwin thought the fixity of species were fixed because of notions got from the Old Testament. Granted, there may have been some who were not biblically influenced, but, by far, most were. Give me a few examples of those who did not get there views on species from the Old Testament. I don’t think you will find many compared to the many who did.

But doesn’t it greatly oversimplify things to say that philosophers and scientists who continued to believe in the constancy of species and in some kind of intelligent design did so only because of their belief in the Old Testament account of creation?   The philosophical and scientific situations were much more complex than that.

As Ernst Mayr, Daniel Dennett, and others have pointed out, essentialism and finalism (teleological ideas) prevailed among many scientists of the time and surely among most philosophers (since Plato and the ancients advanced that perspective on reality) even after belief in the creation story of the Old Testament had largely been abandoned. Below I include some quotes from Ernst Mayr’s great book, The Long Argument – Charles Darwin and the Genesis of Modern Evolutionary Thought.

“Even the geologist Charles Lyell, whose work profoundly influenced Darwin — was a theist who believe that species were created by God’s hand. In all the writing s of the naturalists, geologists, and philosophers of the period, God played a dominant role. (Mayr, 12,13) . . “The reason why Lyell, like Henslow, Sedgwick and all the others of Darwin’s scientific friends and correspondents in the middle of the 1830s , accepted the unalterable constancy of species was ultimately a philosophical one. The constancy of species – that is, the inability of a species, once created, to change — was the one piece of the old dogma of a created world that remained inviolate after the concepts of the recency and constancy of the physical world had been abandoned.” (op.cit., Mayr, 17)

Under the essentialist philosophy all living species were fixed and eternal. This philosophy had long been the prevalent one and had very little to do with religious belief in creation:

“Essentialism had dominated Western thinking for mare than 2000 years, going back to the geometric thinking of the Pythagorians. . . . Essentialism, as a definite philosophy, is usually credited to Plato, even though he was not as dogmatic about it as some of his later followers, for instance the Thomists. . . .
“All of Darwin’s teachers and friends were … essentialists. For Lyell, all nature consisted of constant types, each created at a definite time. “There are fixed limits beyond which the descendants from common parents can never deviate from a certain type. . . It is idle … to dispute about the abstract possibility of the conversion of one species into another … (Lyell 1835: 162) For an essentialist there can be no evolution: there can only be sudden origin of a new essence by a major mutation or saltation.” (Mayr, 40-41)
“Virtually all philosophers up to Darwin’s time were essentialists. Whether they were realists or idealists, materialists or nominalists, they all saw species of organisms with the eyes of an essentialist. They considered species as “natural kinds,” defined by constant characteristics and sharply separated from one another by bridgeless gaps. The essentialist philosopher, William Whewell stated categorically, “Species have a real existence in nature, and a transition from one to another does not exist.” (1840, 3:626) For John Stuart Mill, species of organisms are natural kinds, just as inanimate objects are, and [kinds are classes between which there is an impassible barrier.]”
“Essentialism’s influence was great in part because its principle is anchored in our language, in our use of a single noun in the singular to designate highly variable phenomena of our environment, such as mountain, home, water, horse, or honesty. . . The simply noun defines the class of objects. Essentialistic thinking has been highly successful, indeed absolutely necessary, in mathematics, physics, and logic. The observation of nature seemed to give powerful support to the essentialists’ claims. Wherever one looked, one saw discontinuities — between species, between genera, between orders and all higher taxa. Such gaps as between birds and mammals, or beetles and butterflies, were mentioned often by Darwin’s critics.” (Mayr, 40-42)

Although these ideas were consistent with Biblical accounts of the origin and nature of living forms, essentialism was not a philosophy gotten from Biblical accounts of creation at all. It developed apart from belief in the Old Testament account of creation. Many scientists and philosophers who held to it did so independently of any belief in Genesis. Hence, they were reluctant to accept Darwin’s claim that species changed and even gave rise to new species on the basis of philosophical and what they saw as scientific reasons, not the doctrine gotten from the Old Testament.

Among these philosophers and scientists we find: British philosophers of science: Wm Whewell, JS Mill, J. Herschel — other philosophers holding to teleological views of biology: Leibniz , J.G. Herder, I Kant — scientists: German biologists of the19th century: K E von Baer, Eduard von Hartmann held the teleological concepts of biology. Natural theology (study of nature to reveal God’s design leading to perfection), with its emphasis on design (leading to perfection) was strong in England at the time of Darwin, “all of Darwin’s teachers and peers particularly Sedgewick, Henslow, and Lyell were confirmed natural theologians. This was Darwin’s conceptual framework when be began to think about adaptation and the origin of species.” (Mayr, 55) None of these philosophies: essentialism, teleology, and natural theology were simple applications of the Old Testament.

Pablo also objected to my statement that many people in Darwin’s time could simply not accept the idea that human beings – with their great mental capabilities, moral,  and religious aspirations – could be explained as evolving from earlier forms of animal life. This difficulty which characterized much of the thinking of the middle nineteenth century, and which is still present today, did not always arise from religious doctrine.

Pablo remarked:

Well, I think you’re exaggerating a bit. There were some Greek thinkers who suggested evolution so it wasn’t really that new of a suggestion.

Of course, the idea of evolution was not originated by Darwin.  But I failed to see the relevance of this to the issue of the great difficulty that many people — not only religious people — have in accepting the idea that humans evolved from earlier species. Yes, the idea of evolution has been floating around, at least since the time of Empedocles and  Epicurus.  Many people, including the grandfather of Charles Darwin, had proposed a theory of evolution. But these were mainly just philosophical ‘theories’ which did not rise to the level of scientific hypothesis, supported by empirical evidence and subject to testing, as was the case with Darwin’s theory natural selection.
Pablo also asserted that “… the notion of Darwinian evolution is far simpler and inferior a hypothesis to what was accomplished by Einstein and the founders of QM. ”
Again, I did not see the relevance of these remarks. The issue at hand was one relating to biological evolution. What do Einstein’s relativity physics and QM have to do with that?
I had also stated that scientists of the time (naturalists, geologists, etc. and even skeptical philosophers like David Hume) simply could not accept the idea that a natural, material process like natural selection could explain the presence of human life and human reality. As an example of this reluctance to apply the theory to natural selection to human beings, I noted that even Wallace, co-founder of natural selection, who could comfortably accept evolution from earlier life forms in the case of non-human animals, balked at the idea that this also might apply to humans.

Pablo replied:

I find that surprising (if true). Perhaps he wasn’t familiar with the thoughts of Empedocles (5th century B.C.E.) and others.

Again, what was the relevance here?   Neither Hume’s inability to see natural evolution as explanatory of life forms nor Wallace’s difficulties concerning Darwin’s Descent of Man had anything to do with their alleged ignorance of the Empedocles or any other pre-Darwinian evolutionary theory (of which there were numerous). Wallace, like many others since Darwin’s book on the descent of humans, simply could not fathom how a natural, materialistic process like natural selection could ever give rise to human beings with their intellectual and moral capabilities. Wallace was comfortable with a naturalistic account of the evolution of non-human animals; but with humans, he drew the line, so to speak.

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