Despite his amply documented religious ambivalences there are clear signs that Charles Darwin was never finally able to “close his account” with God. As late as 1870 he wrote to Joseph Hooker that he felt his theology was “in a muddle.” He found it difficult to conceive of the universe as having arisen by blind chance yet could perceive no evidence of consistently beneficent design. Three years later in a letter to a Dutch correspondent he wrote of the design/God issue as being “beyond the scope of man’s intellect” and just four years before his death proclaimed the problem “insoluble.”¹

Religion and Biology in Conflict

Darwin’s spiritual life and biological work were so interdependent that — as he saw matters — if his theory of natural selection were once proved incontrovertible, this would entirely rule out the theory of any tutelary deity having overseen the development of life on earth.² All would be the sole result of chance mutations and natural selection. He steadfastly refused the harmonizing, bridge-building entreaties offered him by Charles Lyell, Charles Kingsley, and others of his circle to the effect that natural selection could simply be understood as the operational modality which God had chosen to create His creatures.

His work and beliefs being so indissolubly linked, it is inevitable that the residue of religious faith that Darwin retained from his early years caused him serious pause when he began to assess the epistemological status of his biological work. For if life had really arisen by providential guidance, what price his strictly secular version of life’s evolution?  This was a circle it was clearly not easy to square and his fretting over the uncompromising binary could sometimes make him appear as a latter-day avatar of the ancient Greek philosopher Pyrrho (who doubted whether mankind had adequate grounds for claiming any knowledge with absolute certainty). Darwin certainly evidenced an ultra-pyrrhonist streak when he questioned whether his own reasoning, which in his opinion had descended from lowly and unreliable baboon ancestry, could be a dependable guide to truth at all. 

Given his inability to resolve fundamental conflicts it was perhaps inevitable that Darwin in his later decades even began to harbor doubts about the efficacy of his pièce de resistance, natural selection, with its (claimed) capacity to create the whole spectrum of the world’s life forms autonomously. Could such a positive and creative process, he asked himself, have been set in train by such a negative phenomenon as natural selection, an entity which Darwin, at the behest of many well-intentioned friends, eventually consented to revise downward to reconceptualize more clearly and in more modest and realistic terms as “natural preservation”?  The trouble in the latter case of course was that notions of naturalistic evolution would now seem to be less logically defensible since mere preservation, by definition, cannot at the same time be creative. 

Ascending Mount Improbable

Hence, following first publication of the Origin in November 1859, Darwin began casting around for supplementary theories to that of natural selection, even reverting to once firmly rejected evolutionary ideas.³ For now he was even prepared to reconsider the Lamarckian/Erasmian idea of the relative use/disuse of organs as a co-determinant of biological development. This is exemplified when in his Descent of Man (1871) he found himself caught up in the challenging position of trying to explain how an ape might have “transitioned” into a human being. For the intuitively obvious morphological link between ape and (wo)man becomes on closer inspection considerably less straightforward than it might superficially appear — something shown up very clearly in the different language competences of apes and humans.

How was Darwin’s particular “Mount Improbable” to be ascended and the decidedly “uphill” transition from ape to human explained? To establish a convincing evolution of ape to human it would first be necessary to establish that simians could over time have increased their communicative vocabularies so as to transform relatively inarticulate emotional cries into specific vocal symbols. But this in turn brings up the related problem of how to explain the rapid mental processing on which articulate speech depends. Without the simultaneous co-adaptation of the simian brain how could the facility of speech, which depends on the interdependent agency of the brain in tandem with the specialized organs of vocal articulation, have developed by the largely unguided processes of natural selection?  In other words, how could chance allied to natural selection have acquired the uncanny capacity to synchronize operations? There are clear signs that Darwin at length found this problem to be so intractable that he was forced back on what he had once denounced as the Lamarckian heresy in order to put together a tolerably coherent explanation.

In order to definitively prove the ape/(wo)man connection it would be necessary to point simultaneously to a precise morphological and neurological pathway of development. By contrast, the explanation Darwin advanced in The Descent of Man was, it must be noted, excessively speculative and ill-focused. It is particularly telling that he felt it necessary to appeal here to Lamarckian ideas in order to put together his rather flimsy conjecture. He writes in Descent,

The mental powers of some earlier progenitor of man must have been more highly developed than in any existing ape, before even the most imperfect form of speech could have come into use; but we may confidently believe that the continued use and advancement of this power would have reacted on the mind itself, by enabling and encouraging it to carry on long trains of thought.⁴ [Emphasis added.]

Passing quickly over the suspicious overuse of the conditional tense (compare the number of conditional “must haves” and “could haves” in the cited words) and that rather nervous, whistling-in-the-dark phrase “we may confidently believe,” it is his dependence on the supposedly discredited Lamarckian idea of the use/disuse of organs which is most conspicuous here since such a conception is not consistent with his original theory of natural selection. It appears that Darwin at this point was coming perilously close to that “apostasy from his own theory” for which Wallace was arraigned in the mid 1860s. At the very least, we sense that Darwin’s trumpet was giving forth a less certain sound in 1871 when we contrast it with the more confident but less thought-through development of his ideas in the period 1838-1859. His loss of confidence in his prior convictions may in turn have contributed to the fact that some later scientists too found it difficult to lay the ghost of Lamarck to rest, and this despite the fact that 20th-century advances in knowledge of Mendelian genetics appeared to rule out a Lamarckian evolutionary pathway.⁵

Re-enter Lamarck

The lure of Lamarck was exemplified most strikingly in the case of early 20th-century Viennese biologist Paul Kammerer and the unhappy affair of the “midwife toad.” The highly regarded Kammerer made the following astounding claim, which I cite here in the words of his modern biographer:

Kammerer took a type of toad that is one of the few amphibian species that mates on land and forced them to breed in water. As a result the males developed nuptial pads [= adhesive calluses] which are regularly found on other male toad species. These nuptial pads help the male toad grasp the slippery female when they copulate in water. Kammerer asserted that not only was he successful in inducing the development of nuptial pads but also that they were passed on to the next generation.⁶

Unfortunately, it was later revealed that the mating pads had been faked by the use of dark ink stains and a short time after this discovery Kammerer was moved to take his own life.

There is no doubting the attractiveness of the Lamarckian theory of acquired characteristics and their supposed heritability. It promotes the comforting notion that parents can pass down not only their wealth and property to their progeny but also the benign results of their own physical efforts at self-improvement.⁷ It is without doubt a more inspiring philosophy than is Darwinism; but such sentimental considerations were an extraneous issue to Kammerer who simply found himself unable to accept the postulation that “natural selection” possessed the efficacy claimed for it by its originator. Hence, exactly like the later Darwin himself, Kammerer was driven — apparently at whatever cost — to seek a Lamarckian supplement to prop up what he deemed the inadequate Darwinian theory. 

 A similar scenario arose in the case of  the late polymath Arthur Koestler who was also moved to flirt with Lamarckian ideas out of a dissatisfaction with Darwinism as a defensible evolutionary pathway.⁸ Koestler felt that Darwinian mechanisms could be at best only part of the picture, claiming that “there must be other principles and forces at work on the vast canvas of evolutionary phenomena.”⁹ He cited the veteran Ludwig von Bertalanffy on this point, Bertalanffy having been one of the distinguished contributors to the interdisciplinary conference of internationally renowned scientists and scholars organized by Koestler in Alpbach in 1969 entitled Beyond Reductionism:¹⁰

If differential reproduction and selective advantage are the only directive factors of evolution, it is hard to see why evolution has ever progressed beyond the rabbit, the herring or even the bacterium which are unsurpassed in their reproductive capacities.¹¹

In light of this much-reported deficiency in the explanatory power of Darwinian theory, Lamarckism was the idea to which Koestler was drawn as at least one possible stratagem for plugging the Darwinian gap.

Theology and Biology

The Darwin who had once described his theological position as muddled became no less bewildered towards the end of his life, a fact which is illustrated by two letters he wrote in the final decade of his life. In a famous letter to his botanist friend Joseph Hooker of February 1, 1871 he wrote, 

It is often said that all the conditions for the first production of a living organism are now present, which could ever [= always] have been present — But if (and Oh! What a big if?) we could conceive in some warm little pond with all sorts and ammonia and phosphoric salts, — light, heat, electricity etc., present, that a protein compound was chemically formed, ready to undergo still more complex changes, at the present day such matter would be instantly devoured, or absorbed, which would not have been the case before living creatures were formed.¹²

Yet the same Darwin who to all appearances set so much store by his theory of naturalistic evolution — enthusing unguardedly about an origin of life from spontaneous generation — was nevertheless capable of writing in his 1876 Autobiography of 

the extreme difficulty or rather impossibility of conceiving this immense and wonderful universe, including man with his capacity of looking far backwards and far into futurity, as the result of blind chance or necessity. When thus reflecting, I feel compelled to look to a First Cause having an intelligent mind in some degree analogous to that of man; and I deserve to be called a Theist. 

It is clearly not possible to postulate at one and the same time that sentient beings are the result of divine creation and of a random chemical reaction, and this contradiction underscores Darwin’s abiding ambivalence on the subject of creation and evolution. These theological ambivalences also had a correlative in his work as a naturalist where his position remained essentially interrogative as he shifted in his mind between one theoretical possibility and another.

“To Be or Not to Be…”

It should be stressed that Darwin’s hesitancies and diffidences as a biologist were real and not the product of false modesty, as is evidenced in the no fewer than five amended editions of the Origin which followed in quick succession in the decade following the first edition of 1859. In the later, revised editions, he did his honest best to integrate criticisms made by others (to which he always remained acutely sensitive). There was in him little of the blinkered zealot which we tend to associate with some modern proponents of his theory. Darwin had always conceded that he was advancing his present theory until such time as a better one might present itself.  It seems that what at first blush might be mistaken for mere gentlemanly humility was in fact meant in earnest.

It is therefore likely that Darwin would have positively welcomed many modern findings as a means of complementing and enriching his own work, and the last few decades have in fact provided an intriguing addendum to the whole Darwin/Lamarck saga. The idea of heritability “beyond genes” is now regularly studied under the umbrella rubric of epigenetics;¹³ and although some results of this recent research have proved resistant to definitive interpretation, modern scientific advances have at the very least amply confirmed the worries of Darwin and the suspicions of Kammerer and Koestler that Darwinian explanations could not possibly represent the whole story. (See, for example, the conspectus of diverging modern views covered at length recently by Stephen Buranyi in the UK newspaper The Guardian, asking “Do We Need a New Theory of Evolution?”)

This is surely a factor with an important bearing on the interpretation of the Origin. Many of Darwin’s peers did not conceive of his work as a univocal tract but as a more nuanced discussion document to which some such as Kingsley, Lyell, and even Huxley (who was never able to assent to the proposition of natural selection) had no hesitation about producing their own “minority reports.” In my view it is in such a “dialogic” way that the Origin might most appropriately be read in our own day too — as a commendable effort to penetrate impenetrable mysteries but whose author might best be listened to, in Coleridge’s phrase, “with no presumption of inerrancy.”

Notes

1. See Nick Spencer, Darwin and God (London: SPCK), pp. 96-9.
2. Darwin wrote defiantly to Charles Lyell on this subject, “I would give absolutely nothing for theory of nat. selection, if it require miraculous additions at any one stage of descent.” (Charles Darwin to Charles Lyell, October 11, 1859, Darwin Correspondence Project, Letter no. 253, University of Cambridge, https://www.darwinproject.ac.uk/letter/DCP-LETT-2503.xml.)
3. In later life he appeared touchingly open to incorporating responses to a variety of criticisms leveled at him by other scientists, with the result that, over a decade, the Origin went into no less than five revised editions, its sixth, heavily emended version being markedly different in many respects from the 1859 original. 
4. The Descent of Man and Selection in Relation to Sex, edited by James Moore and Adrian Desmond (London: Penguin, 2004), p. 110.
5. A giraffe for instance cannot elongate its neck (and hence the necks of its progeny) by repeatedly craning towards the higher branches of trees, 
6. Kaus Taschwer, The Case of Paul Kammerer: The Most Controversial Biologist of His Time (Montreal: Bunim and Bannigan, 2019), p. 9.
7. See on this point Arthur Koestler, The Case of the Midwife Toad (London: Hutchinson, 1971), pp. 27-30.
8. Koestler cited with approval the view of the mid 20th-century scientist C. H. Waddington that chance mutation was like throwing bricks together in heaps in the hope that they would arrange themselves into an inhabitable house.
9. Koestler, Midwife Toad, p. 129.
10. Beyond Reductionism: The Alpbach Symposium, edited by Koestler and J. R. Smythies (London: Hutchinson, 1969). Cf. in that volume Ludwig von Bertalanffy’s “Chance or Law,” pp. 56-84, and for a balanced assessment of Koestler’s intellectual achievements and weaknesses Michael Scammell, Koestler: The Indispensable Intellectual (London; Faber and Faber, 2011). 
11. Koestler, Midwife Toad, p.129.
12. Darwin Correspondence Project, Letter no. 7471: https://www.darwinproject.ac.uk/letter/DCP-LETT-7471.xml
13. See John and Mary Gribbin, On the Origin of Evolution: Tracing Darwin’s Dangerous Idea from Aristotle to DNA (London: Collins, 2020), pp. 230-252 (chapter titled “The New Lamarckism”), Paul Davies’s recent chapter entitled “Darwinism 2.0” in his The Demon in the Machine: How Hidden Webs of Information Are Solving the Mystery of Life (London: Penguin, 2020), pp. 109-143, and Nessa Carey’s The Epigenetics Revolution: How Modern Biology is Rewriting our Understanding of Genetics, Disease and Inheritance (London: Icon, 2011).