Editor’s note: We are delighted to present a series by Neil Thomas, Reader Emeritus at the University of Durham, “Natural Selection: Discovery or Invention?” Find the full series here. Professor Thomas’s recent book is Taking Leave of Darwin: A Longtime Agnostic Discovers the Case for Design (Discovery Institute Press).
Charles Darwin tended to reverence those with whom he sensed an affinity. This was amply demonstrated in his relationship to his older friend and mentor, Sir Charles Lyell, author of the magisterial Principles of Geology (three volumes, 1830-33),1 the first volume of which was published in time for Darwin to be able to take it with him aboard the Beagle. Many important aspects of the Origin of Species had their intellectual starting point in Lyell’s Principles of Geology. For in those volumes Lyell developed and successfully illustrated his theory of “uniformitarianism” — meaning the natural and non-divinely directed evolution of geological features over large tracts of deep time. This new understanding of inanimate nature’s workings came to oust the theory of catastrophism, the previous idea that the terrestrial ecosphere had been fashioned by God in a series of disasters and remakings culminating after many extinctions in the eventual emergence of Homo sapiens.
Comparable Patterns of Evolution
Catastrophism viewed the planet as having been molded by forces far more powerful than any observable at the present day. Hence, the thinking went, these forces must have had a supernatural causation and have been set in train by God himself. Adherents of catastrophism were essentially practicing science from a platform of Biblical conviction, foregrounding what was known as the diluvial theory of the Biblical Flood and the related story of Noah’s Ark related in the Old Testament. Darwin thought of this conception as a useful analogy to transfer to the biological sphere. Just as Lyell had rejected the abrupt transitions postulated by catastrophism, so Darwin set his face against the notion of supernatural “saltations” (jumps) in the sentient world of biology — that is, the notion that God had created various animals in a trice or single “leap” (Latin saltus). For him, speciation — the development of different animal-types — had also occurred over a similar period of geological time in a process where originally simple organisms had modulated into more complex animal forms. For Darwin, biology and geology both showed comparable patterns of gradualistic evolution.
Thinking by Analogy
Lyell’s Principles of Geology may then be said to have provided a foundational intellectual springboard for the Origin of Species, for which reason the geologist was to become popularly known as Darwin’s John the Baptist. Lyell having mapped out the intellectual territory to be traversed, the cross-over from geology to biology appeared plain sailing to Darwin. His way of thinking by analogy would seem to have been that, if there was a story of natural evolution in the geological record, so too might there be a similar story to tell in the study of sentient beings if he were but to map Lyellian ideas on to the biological domain. As Darwin saw matters, all that now remained for him to do was to transfer Lyell’s geological principles over to his own area of special interest and it would be a case of “job done.”
Lyell, however, it should be noted, disagreed with Darwin’s rather wholesale transference of his geological modus operandi to the sentient world for being undiscriminating and simplistic. Notoriously, some analogies are closer than others, and for Lyell Darwin’s was one analogy too far. Lyell was convinced that a divine causation could be excluded from the inanimate realm of geology but not from the living world of biology, and that analogy can be a false friend. One is reminded of Samuel Johnson’s objection to the elaborate metaphors and extended poetic conceits of John Donne and other “metaphysical” poets of the 17th century. Such were poems, chided Johnson, where “the most heterogeneous ideas are yoked by violence together.” So in the final analysis, opined Lyell in his sonorous Victorian idiom, the origin of variations remained a mystery involving causes “of so high and transcendent a nature that we may well despair of ever gaining more than a dim insight into them.”2
Consequential Small Talk
In formulating his ideas Darwin derived inspiration from a wide range of sources. One unheralded idea which came as something of a surprise to him came to light during his stay in the South Sea islands in the 1830s. But it arose not from his fieldwork but rather in the course of some salon discussion with a colonial civil servant, Nicholas Lawson. Darwin later recalled that he was much indebted to a purely chance remark of the colonial vice-governor who claimed that he could tell by merely looking at a tortoise from which island of the archipelago it had come.3 Darwin, somewhat taken aback, confessed that he, dedicated naturalist though he was, had not noticed these variations. It was this conversation with the colonial official that turned Darwin’s thoughts towards the subject of adaptive physiological change to differing environments and the potentialities for transmutation of species. This informal conversation was fortunate for Darwin since the colonial official’s small talk had shown him the essential bridge which linked with that area of transmutational speculation with which Darwin would have been already acquainted via his grandfather, Erasmus, and which went on to prove essential to the grandson’s later ideas of speciation.
Next, “The Legacy of Erasmus Darwin.”
- Charles Lyell, Principles of Geology, edited by James Secord (London: Penguin, 1997).
- Cited by Neal Gillespie in Charles Darwin and the Problem of Creation (Chicago: Chicago UP, 1979), pp. 110-111.
- I am indebted for this information to John Hedley Brooke, Science and Religion: Some Historical Perspectives (Cambridge, Canto, 2014), pp. 348-50.