A Prolegomena to A History of Evolution: Taking Biology from Metaphysics

A little learning is a dang’rous thing;Robert Bowler
Drink deep, or taste not the Pierian spring:
There shallow draughts intoxicate the brain,
And drinking largely sobers us again.
Fir’d at first sight with what the Muse imparts,
In fearless youth we tempt the heights of Arts,
While from the bounded level of our mind
Short views we take, nor see the lengths behind;
But more advanc’d, behold with strange surprise
New distant scenes of endless science rise!
So pleas’d at first the towering Alps we try,
Mount o’er the vales, and seem to tread the sky,
Th’ eternal snows appear already past,
And the first clouds and mountains seem the last;
But, those attain’d, we tremble to survey
The growing labours of the lengthen’d way,
Th’ increasing prospects tire our wand’ring eyes,
Hills peep o’er hills, and Alps on Alps arise!

(Alexander Pope, An Essay on Criticism)

To the Greeks, drinking from the Pierian Spring brings great knowledge and inspiration. Thus, Pope is explaining how if you only learn a little it can “intoxicate” you in such a way that makes you feel as though you know a great deal. However, when “drinking largely sobers” you, you become aware of how little you truly know.

I was reminded by Pope’s couplet over the weekend, when someone I know very well broached the topic about evolution and the church—particularly his church. He bemoaned his church’s alleged anti-evolutionary stance—although the nature of the conflict was not entirely clear to me. I asked what, exactly, was so troubling. He replied that “the majority of the scientific community hold evolution to be true,” and thus it followed, in his mind, that this church needed some updating. I pressed him to expand on this, but he merely repeated anecdotal “evidence” gleamed from popular accounts, namely newspaper editorials, magazines, television programs, and the like.  Now, this person is highly educated, but neither in the biological sciences nor in the history of ideas. His knowledge on the subject is based on what Neil Postman has called “the news of the day”; that is, the massive flow of “decontextualized” information over a vast medium. But that kind of knowledge is narrative, stories or myths the media (de)constructs for its audiences.

This had me thinking about my own research interests; namely, tracing the genesis, growth, and dissemination of the narratology of the Scientific Revolution in nineteenth-century Europe. The Biological Revolution is a similar narrative, only constructed later, mostly in the twentieth century, and particularly in North America. What this narrative ignores is that evolutionary biologists are constantly involved in some controversy. Despite appearances, there is tremendous disagreement among practicing scientists. Some of Darwin’s staunchest supporters disagreed with him on key issues. For example, T.H. Huxley, Joseph Hooker,  and Alfred Russel Wallace were all strong supporters of evolutionary ideas, and yet all argued with Darwin privately in letters and sometimes in print. More recently few know of the controversies surrounding John Maynard Smith,  Richard Dawkins, Daniel Dennett and Stephen Jay Gould and his colleague Niles Eldredge. These controversies involve complexities that the media ignore because it is messy. No one likes a messy story. We want black and white. We want to cheer for heroes and condemn the villains.

So this inevitably raises the question, “How could these individuals have supported Darwin if they did not believe in some of his most basic ideas?” Part of the answer becomes clearer when we realize that Darwin’s theory of evolution can be divided into distinct sub-theories, which are, for the most part, independent of one another. German-American biologist Ernst Mayr breaks these sub-theories into five categories:

  1. Evolution as such: This is the idea that evolution takes place.
  2. Common descent: This is the idea that every group or organisms (mammals, e.g.) is descended from a common ancestor, and that all organisms can be traced back to a single origin of life.
  3. Multiplication of species: This is the idea that species multiply. They may do this by splitting into two distinct species at various different times during their evolution.
  4. Gradualism: This is the idea that evolution is an accumulation of small changes. New types do not suddenly appear. That is, there is no saltation.
  5. Natural selection: Evolution comes about because there is an abundance of genetic variation in every generation. Relatively few individuals survive and pass along their favorable genetic characteristic to the next generation.

Some of these are more inclusive than others. But it is possible to break Mayr’s five sub-theories down further. Some authors have even cited eight or more components. At any rate, once this point is understood, it is easy to see how scientists such as Huxley could have counted themselves among Darwin’s supporters when they disagreed with him on major points.

A better answer, as Nancy Pearcey and Charles Thaxton perceptively observe in their The Soul of Science: Christian Faith and Natural Philosophy (1996), is that the revolution in biological sciences blossomed fourth suddenly in the eighteenth and nineteenth centuries, and in a welter of contrary philosophies and approaches. Biological theories of those centuries jumped from mechanistic to vitalistic, from reductionistic to holistic, from essentialist to transformist, from radical materialism to natural theologians who regarded living things as evidence for belief in God.

The contrasting theories sort themselves out once we realize that biology was nourished by the same streams of thought that dominated the physical sciences in previous generations; namely the Aristotelian, Neo-platonic, and Mechanistic worldviews. Grasp these three worldviews and you have the tools to sort through the rich diversity making up the history of biology and to understand the intellectual commitments motivating individual figures. In other words, advocates of various interpretations of life ultimately borrowed their biology from their metaphysics. Each metaphysical tradition primed its adherents to look for certain kinds of facts and to apply certain interpretations.

For example, the Aristotelian worldview, though discredited in physics and astronomy, remained vigorous in natural history. Its major theme was that organic structures must be understood according to built-in purposes. The Aristotelian approach was particularly popular with anatomists, who were impressed with how perfectly the eye is constructed for seeing and the ear for hearing. Many saw in the wonderful “fit” between structure and function the hand of a wise Creator. In addition, Aristotelian logic was used in the construction of classification systems to organize the vast array of living things. Aristotelians tended toward the descriptive side of biology. They interpreted the order in the organic world as an expression of the divine plan of creation; their reasoning was the logic of categorization; their method was observation in the wild. The explosion of biological information gathered by European explorers made the need for biological classification paramount. Physician William Harvey (1578-1657), botanists John Ray (1627-1705) and Carl Linnaeus (1707-1778), and zoologist Georges Cuvier (1769-1832) all displayed a remarkable Aristotelian tone in their work.

By contrast, Neo-platonism stressed immanent semi-spiritual “active principles” as formative forces in nature. The nineteenth century witnessed a great revival of Neo-platonism through the romantic movement, especially in Germany where it developed into Naturphilosophie (nature philosophy). The romantic biologists embraced a form of pantheistic vitalism, especially popular among embryologists, who sought an inner Law of Development to explain organic forms.

By drawing an analogy between embryonic development and the development of categories of organisms, romantic biologists were the first to construct theories of evolution. Just as individuals move up through several stages of development, so all of life was presumed to move up the “great chain of being” from simpler forms to humanity. In most cases, this was not evolution as the term is used today but rather as its literal definition suggests—an “unfolding” of a preordained pattern, the gradual realization of an immanent or built-in pattern. Like earlier Neo-platonists (Paracelsus, van Helmont, Leibniz), the romantic biologists often spoke of “seeds” in nature—hidden, latent powers that unfold over time. Each category of organism was regarded as the realization of such a seed.

The romantic biologists also searched for fundamental anatomical patterns for each class of organisms. They referred to these patterns as “archetypes”—a term reminiscent of Plato’s perfect and eternal Ideas. Hence romantic biology is often described as an idealist philosophy of nature; the search for archetypes was labeled Transcendental Anatomy. The romantic biologists interpreted the order in the organic world as a progression up the chain of being, a succession of archetypes; they reasoned by analogy; their method was historical. The astronomer and biologist Pierre Louis Moreau de Maupertuis (1698-1759) was one of the first to recognize that a simplistic Newtonian paradigm of “forces and motions” was inadequate for biology.  French naturalist, mathematician, cosmologist, and encyclopedic author, Georges-Louis Leclerc, Comte de Buffon (1707-1788), once he had become acquainted with Leibniz’ work, wrote a multi-volume natural history that became a key influence in the rise of romanticism and Naturphilosophie. A contemporary of Cuvier, Jean Baptiste Pierre Antoine de Monet, Chevalier de Lamarck (1744-1829) reacted against what he regarded as the dry systematic approach of the Aristotelian tradition. According to Lamarck, the essence of life is flux, motion, change, and central to his philosophy of nature is the organism as it strives to adapt and develop.

And finally there was the Mechanistic worldview, which came to biology through Descartes, with his proposal that living things (animals and the human body) are automatons, operating solely by physical laws. Mechanistic philosophy appealed particularly to physiologists studying the way the body operates. Early physiologists focused on the mechanical operation of limbs and joints; later they experimented with chemical reactions in the body. Mechanists interpreted the order in the organic world as a result of order in the physical world, in the atoms and chemicals that comprise living things; they reasoned by analysis; they championed the method of controlled experiment. We can distinguish two groups of mechanistic biologists during the period. One group was motivated by political and religious concerns as much as by biological ones. They hoped that a radical materialism would sap the supernatural sanctions of Christianity and in so doing not only shake the dogma of the churches but also undermine the legitimacy of contemporary absolutist princes. This group included figures such as Karl Vogt (1817–1895), Jacob Moleschott (1822–1893), and Ludwig Buchner (1824–1899). They turned their hand to the popularization of science, using it to support materialism. The second group of mechanistic biologists were more moderate, focusing on physiology, not politics. They tended to treat reductionism primarily as a methodology, not an all-embracing philosophy. This group included figures such as Emil du Bois-Reymond (1818–1896), Karl Ludwig (1816–1895), and Hermann von Helmholtz (1821–1894).

The three traditions adumbrated here did not, of course, remain exclusive from one another. Once terms or phrases became common usage in one tradition, they tended to spill over into general discourse. Adherents of other traditions might pick them up and pay them lip service without necessarily accepting their metaphysical context.

On the other hand, there were some who consciously sought to reconcile the different traditions. Richard Owen (1804–1858), a student of Cuvier, was subsequently influenced by romantic biology and worked out a synthesis of the two. Louis Agassiz (1807–1873), the Swiss naturalist who headed the zoology department at Harvard University, likewise combined elements of Aristotelianism with the idealistic progressivism of Naturphilosophie. In Germany Ernst Haeckel (1834–1919) grafted Darwin’s materialistic evolution onto the roots of romantic biology and became one of Darwin’s most vigorous popularizers.

Clearly, science is not simply a matter of observing facts. Every scientific theory also expresses a worldview. Philosophical preconceptions determine where facts are sought, how experiments are designed, and which conclusions are drawn from them. It is only by grasping the worldview traditions that have shaped the development of biology that we really understand what motivated a Cuvier, a Buffon, or a Darwin.

But we might wonder whether these worldview traditions discussed here are still alive today. The answer is yes. The most visible is the mechanistic tradition. Mainstream academic biology is adamantly committed to a materialist, reductionist form of mechanism. And as noted in the beginning of this post entry, controversies and conflicts in the biological sciences continue to exist today. According to the noted British geneticist John Maynard Smith, Harvard paleontologist Stephen Jay Gould is “a man whose ideas are so confused as to be hardly worth bothering with.” Oxford University zoologists Richard Dawkins charges Gould’s view of evolution is based on fundamental misunderstanding. Tufts University philosopher Daniel Dennett goes further. According to Dennett, Gould is “a would-be revolutionary” who has mounted a series of attacks on conventional Darwinism over the years. Furthermore, Dennett says, as the best-known writer on evolutionary topics, Gould has had an influence that is “immense and distorting.” Gould must have some “hidden agenda,” Dennett speculates.

Gould, on the other hand, brands Maynard Smith, Dawkins, and Dennett as “Darwinian fundamentalists,” who place an emphasis on one component of Charles Darwin’s theory and “push their line with an almost theological fervor.” Maynard Smith, he says, has apparently gotten caught up in an “apocalytpic ultra-Darwinian fervor.” Dennett’s writings, he adds, are characterized by “hint, innuendo, false attribution and error.”

Maynard Smith, Dawkins, Dennett, and Gould are not the only individuals engaged in this controversy. For example, Gould’s colleague, paleontologist Niles Eldredge has also critized Dawkins, Dennett, and Maynard Smith. So have various other scientists, including as H. Allen Orr, Steven Pinker, Leda Cosmides, John Tooby. The controversy is ongoing and it is not likely that the argument will end soon. The differences between all these scientists arise not from the scientific data, but their interpretations of it. There are fundamental philosophical differences between them. Dawkins, Maynard Smith, and other orthodox Darwinians are reductionists who see only one important factor in evolution. Gould and Eldregde, on the other hand, describe themselves as pluralists who see evolution as something that is much more complex. Thus the differences in outlook have led not one but a variety of different controversies.

This post entry is merely an introduction to a vastly complex subject. I have recently acquired Peter J. Bowler’s Evolution: The History of an Idea (2009), recognized as a comprehensive and authoritative source on the development and impact of this most controversial of scientific theories. This twentieth anniversary edition is updated with a new preface examining recent scholarship and trends within the study of evolution. For those who are interested in going beyond “the news of the day,” Bowler’s book is a good start.

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