A Method to Darwin’s Evolution

The Triumph of the Darwinian Method

Michael T. Ghiselin

University of California Press (1969), 287 pp.

 

The Darwinian Revolution: Science Red in Tooth and Claw

By Michael Ruse

University of Chicago Press (1979). 320 pp.

 

Reviewed by Tom Gwaltney

 

            With the publication in 1859 of his Origin of Species, Charles Darwin revolutionized our view of the world. In The Triumph of the Darwinian Method (1969), Michael T. Ghiselin argues that Darwin’s book caused an “immediate and cataclysmic shift in outlook,” [i] while Michael Ruse in his work, The Darwinian Revolution: Science Red in Tooth and Claw (1979), opines that Darwin caused changes in thinking that went far beyond biology, affecting “beliefs and behaviors from the most trivial to the most profound” [ix]. Ghiselin and Ruse investigate how this revolution took root and the methods by which Darwin achieved his breakthrough; however, Ruse focuses on the scientific and social interactions that shaped Darwin, while Ghiselin concentrates on Darwin’s scientific approach.

            Ghiselin examines how Darwin’s varied scientific investigations could be explained by an overarching methodology – a consistent application of “hypethetico-deductive techniques” [4]. “The entire corpus of Darwinian writings constitutes a unitary system of interconnected ideas,” [12] Ghiselin conjectures, as he sets out to review the varied interests that Darwin pursued – from the expected in geology, biogeography, natural selection, and evolution to the more obscure in barnacles and his study of behavior.

            Ghiselin analyzes the issue of methodology by dividing Darwin’s body of work into basic categories and investigating the scientist’s methods in each. Investigating Darwin’s study of geology, Ghiselin notes the scientist’s debt to Lyell’s Principles of Geology which Darwin read on his voyage on HMS Beagle. However, “it was the active process of testing theoretical notions against concrete experience that made Darwin a scientist. No teacher was necessary, and it was an education of the first rank,” [13] Ghiselin concludes. On natural selection, Ghiselin observes that “innovations amount to more than stumbling upon a new idea” [47] but involve the scientist’s formulation of new hypotheses and the demonstration new ways of attacking established subjects. Therefore, Ghiselin argues, the stress should not be put on whether Darwin was the first to postulate evolution, but rather on the critical thinking that Darwin performed to find new insight on the subject. Thomas Malthus’s Essay on a Principle of Population was the catalyst for Darwin in his innovation of seeing a species in terms of a population. Says Ghiselin in review of Darwin’s methodology regarding his theories in geology, biogeography, and natural section:  “[they] are based on abstract models which have numerous implications and can be readily tested” [76]. Each also reveals a development in thought which explains facts which were previously considered contradictory. Throughout Darwin’s body of work, Ghiselin concludes, “[Darwin] thought. He reasoned systematically, imaginatively, and rigorously, and he criticized his own ideas” [232]. In Ghiselin’s view, the “revolution” was a triumph of the deductive method of a scientist.

            Ruse, in comparison, focuses on Darwin’s interactions within the scientific community, providing a background on the transition within the scientific world from Jean Baptiste de Lamarck’s “chain of being” and George Cuvier’s teleological cosmology, in which organisms were considered “functional wholes” to evolutionism. Concentrating on the reversal of views on evolutionism during the quarter century following 1850, Ruse weaves three threads – the scientific, the philosophical, and the religious. The “revolution” in thinking necessary to understand organic origins, in Ruse’s view, was based on a resolution of the philosophical debate as to what theories fit good science, a solution to the religious problem of how God and man were affected by the philosophical debates, and a network of scientific thinkers upon whose ideological foundations an innovator might draw. Darwin, Ruse contends, was the innovator who could “grasp the essentials of past scientific achievements” and who was not “emotionally and intellectually committed to the past” [5].

            As Ruse unfolds his thesis, Darwin was not, when he left his academics at Cambridge, a professional scientist. It was, in fact, the network of men of science with whom Darwin had become friends that provided him the grounding he needed – men like botanist John Stevens Henslow, geologist Adam Sedgwick, and mineralogist William Whewell. Through these relationships, and at societies like the Geological Society of London, Darwin became intimately involved with geologist Charles Lyell and mathematician Charles Babbage. By the end of the 1830s, Ruse contends, Darwin had become a “professional scientist” through his society with these men and through his practical training in the field and on his voyage on the Beagle.  

            With this groundwork laid, it was through his study of Lyell’s Principles of Geology that Darwin became convinced that geological phenomena occurred gradually (as evidenced in his “Lyellian” approach to the theory of coral reefs which comprised actualism, uniformitarianism, and steady-state theory). Grounded in Lyellian geology, and influenced by his grandfather Erasmus Darwin’s work Zoönomia, Darwin had, in Ruse’s words, a “sympathetic introduction to organic evolutionism” [161]. As a Lyellian committed to inorganic evolutionism, he was pushed towards a similar view for organic evolutionism. Sparked by reading Malthus’s Essay in 1838, Darwin first completed a 35-page sketch in 1842, followed in 1844 by a 230-page essay on his theory of natural selection. Fifteen years later, Darwin published his theory in Origin of Species.

Ghiselin and Ruse diverge on the originality of Darwin’s thought regarding coral reefs. Ghiselin implies that Darwin’s hypothesis on coral reef formation was original and “a strictly rational development of theoretical concepts” [23] in which he applied an “almost ideal model” [24] of the scientific method. But Ruse interprets Darwin’s work differently and states that Darwin did not present his idea that reefs form through subsidence with a “tight deductive network of laws” [62]. Rather, Ruse believes, Darwin put forward his theory as a geologist who was ever conscious of the philosophy of his peers in the Society, such as Herschel and Whewell. Darwin may have been employing good “political” tactics to ensure a balanced reception, Ruse believes. While opinion may have had an influence, here Ghiselin makes a sound argument as to Darwin’s originality, for as Lyell had argued that coral reefs were built on extinct volcanoes, Darwin completely revised Lyell’s position. Darwin did adhere to Lyellian concepts, but Darwin’s solution made even Lyell change his hypothesis.

Ruse, in contrast to Ghiselin, also holds that Darwin’s 1844 essay and Origin were the not simply the product of original thinking, but a result of his society with scientific peers and family. While Darwin’s work was not the “natural culmination of a long line of evolutionists” [200], Ruse states, neither did it spring from the ether. Indeed, Ruse believes, Darwin’s Origin was synthesized because of the scientific network of which he was a part and from which he derived: a Lyellian understanding of geology and sympathy with actualism, the philosophical groundwork in the 1850s for acceptance of universal law which allowed him to bridge artificial and natural selection, and a non-religious family background which allowed him to escape the problem of God and man’s place. However, Darwin waited fifteen years to publish his work in Origin of Species. Ruse and Ghiselin again disagree on the reasons why.

Origin of Species was not published until 1859. In the intervening years Darwin completed a comprehensive, eight-year study of barnacles. This wait is attributed by Ruse to Darwin’s “professionalism.” In 1844, as part of a tightly knit scientific network, Ruse contends that Darwin was aware that most of his peers had great dislike for evolutionism (based on their reaction to Robert Chambers’s anonymously published work Vestiges of the Natural History of Creation). As Vestiges was published in the same year as his essay, and the response was so negative, Darwin, in Ruse’s estimation, did not want to become an unpopular member of the scientific community: “Darwin confessed [to his friend Joseph Hooker] that it was like admitting to a murder” – the murder of Christianity [185].

Ghiselin explains the detour into the study of barnacles in a more straight-forward manner. Ghiselin discounts the notion that Darwin wanted to obtain “practical work in discriminating species” [103] or that barnacles held a “central position in a classification system” [104] Darwin needed to refute for his theory to be valid. Ghiselin postulates that Darwin simply wanted to describe a single species as a “small, personal contribution to the body of taxonomic literature” [104] – as he had done for flatworms previously. Ghiselin contends, and Ruse concurs, that the extended delay caused by the barnacle monograph was not what Darwin had planned. But even if, as Ghiselin states, the barnacle study was to be just a “small, personal contribution,” why did Darwin undertake it at that particular time, coincident with the uproar surrounding Vestiges? Ruse’s explanation of the delay seems more plausible.

            Beyond content, the two books also reflect the differing backgrounds of their authors through their style. Ghiselin, schooled as a comparative anatomist[1], reflects his training in his precise dissection of Darwin’s methodology by an evaluation of Darwin’s approach to geology, biogeography, natural selection, taxonomy, variation, and other topics. Ghiselin’s self-described task here is to “construct a single theoretical system” [6] through which Darwin’s varied investigations can be explained. Indeed, Ghiselin structures each of his chapters as discrete building blocks which present a hypothesis (“Of all Darwin’s works, it is The Descent of Man that in many ways best manifests the nature of his thought” [214]), examine the facts, and come to a conclusion (“The Descent of Man is no product of enumerative or ‘Baconian’ induction, but owes its success to the poser of abstract reasoning which gave rise to it” [230]).

In contrast, Ruse, a professor of history and philosophy, adopts a more conversational style in weaving the scientific, philosophical, and religious threads of his story. Often using the first person, Ruse engages the reader with phrases such as, “Our old friends Lyell and Owen …,” and “I confess I find it difficult to warm to Huxley …” [139]. His aim, as he notes in his introduction, is a discourse on evolutionism for readers who are interested in the history of science, but who may not be professional scholars. Indeed, for the lay reader, Ruse’s approach provides a very accessible overview of the scientific thinking of Darwin’s age.

            Ultimately, Ruse’s integration of historical themes and his multi-causal argument is more satisfying to the reader than Ghiselin’s more narrowly-focused approach. Ghiselin argues that those who claim Darwin did not innovate because his work was based on earlier scientific thought miss the point. In this Ghiselin is correct, but as Ruse observes, “[i]f we are to understand fully why Darwin achieved such success, we must go beyond pure ideas and look at the scientists in their human settings” [250]. Darwin’s methodology was more than solo innovation; it was the result of the threads of scientific, philosophical, religious, social, and political thought of his day. As Ghiselin states, Darwin “obviously learned a great deal from discussions with his associates and from such experiences as a long field trip in 1831” [13] with Sedgwick at the beginning of his career, and he profited from such collegial interactions throughout his investigations. It was within this social context that Darwin’s ability to “think outside the box” – to use a modern turn of phrase – allowed him to weave the disparate threads together.

Darwin, in his Origin of Species, reflects on this process in his final chapter “Recapitulation and Conclusions:”

When we no longer look at an organic being as a savage looks at a ship, as something wholly beyond his comprehension; … when we contemplate every complex structure and instinct as the summing up of many contrivances, each useful to the possessor, in the same way as any great mechanical invention is the summing up of the labour, the experience, the reason, and even the blunders of numerous workmen; when we thus view each organic being, how far more interesting—I speak from experience—does the study of natural history become!

 

Darwin seems to recognize that by weaving together the variety of discourse into his theory of evolution, he had revolutionized how scientists would proceed and how many new questions could be raised. Ghiselin emphasizes this point: “Darwin’s [writings] have continued to serve as the foundation for new research. This was Darwin’s fundamental contribution to scientific thought” [235].

Ghiselin and Ruse, by showing us how Darwin’s views were shaped and how he stretched the views of his day through “the labour, the experience, the reason, and even the blunders” of his years of study, make the reader appreciate how his or her own views evolve through reason and imagination within today’s social constructs. “Science,” as Ghiselin concludes, “is more than a body of knowledge or a method of inquiry. It becomes a part of culture and a way of life” [243]. Ghiselin and Ruse each makes us think about that process. What more could an author ask?