What Exactly Was Darwin's Religion?
At first glance, that question may appear to pose an enigma. For the position that Charles Darwin believed in God is completely untenable. Yet it is certainly also true that Darwin was no arch-atheist.
Somewhere in between is Karl Giberson's attempt to imagine a more sympathetic Darwin by admitting that he was "neither a deathbed convert [as Lady Hope had claimed] nor lifelong crusader against belief in God. He was, in fact," according to Giberson, "a sincere religious believer who began his career with a strong faith in the Bible and plans to become an Anglican clergyman. He did eventually lose his childhood faith, but it was reluctantly and not until middle age, long after his famous voyage on the Beagle" (Saving Darwin, pp. 19-20).
This is the Darwin of the Autobiography, the Darwin who was "very unwilling to give up my belief" and "found it more and more difficult to invent [emphasis added] evidence which would suffice to convince me. Thus," he concluded in a sort of feigned despair, "disbelief crept over me at a very slow rate, but was at last complete" (p. 62). We must be wary of autobiography, remembering, as leading Darwin biographer Janet Browne has noted, that Darwin "was constructing himself in the shape in which he wished to know himself and to be known by" (Charles Darwin: The Power of Place, p. 427).
What was Darwin's actual experience and journey with respect to religion and related metaphysics? Darwin was always a minimalist when it came to such things, but it was a crafty sort of minimalism. For example, at a meeting on September 28, 1881, the prominent German atheist Ludwig Büchner (1824-1899) tried to get an ailing Darwin to admit he too was an atheist. With English atheist Edward Aveling (1849-1898) at Büchner's side, Darwin objected by saying, "Is anything to be gained by forcing new ideas on people?" That is to say, Darwin didn't object to atheism per se but rather for strategic reasons.
Adrian Desmond and James Moore make it quite clear that Darwin was profoundly influenced by materialism years before through his interactions with his fellow Plinians in the "freethinkers" society he joined as a teenager at Edinburgh U. His intimate relationship with Robert Edmond Grant (1793-1874) -- truly an arch-materialist -- during that period is also telling. "Theirs was a decisive meeting," declare Desmond and Moore, "Darwin was coming under the wing of an uncompromising evolutionist. Nothing was sacred for Grant. As a freethinker, he saw no spiritual power behind nature's throne" (Darwin: The Life of a Tormented Evolutionist, p. 34).
It was during this period that young Charles and the senior Grant became close walking companions. To underscore his extracurricular education, Darwin attended 19 Plinian Society meetings where he heard fellow Plinians hold forth on the mind being wholly a production of the brain, the faculties of the lower animals were comparable to man, that the endowments given to man by a Creator was mere "anatomical chauvinism," and so on.
The point is, Darwin's metaphysical exposures ran well ahead of his evolutionary theory. While the young Charles may not have embraced those ideas immediately, he clearly had a fairly complete mental template of what a materialistic worldview would look like, this before he ever set foot on the Beagle. No wonder then that his Notebooks -- begun just a few months after his arrival back in England on October 4, 1836 -- "resound," in science historian Stanley Jaki's words, "with militant materialism" (The Savior of Science, p. 126). Darwin was quite disingenuous about this in his Autobiography, something even Janet Browne concedes.
By the time Darwin left the Plinians in April of 1827 his march towards materialism was ineluctable, and from around 1839 (perhaps even earlier) it was a fait accompli. It is hard to disagree with Howard Gruber that Darwin amassed much of his purported evidence on evolution "after his views were quite well developed."
I have adopted a phrase coined by Scottish theologian Robert Flint (1838-1910) to characterize Darwin's religious belief: he was an agnostic atheist. That is not to say that he might be persuaded by evidence in a god, evidence that he simply found thus far unobtainable. Instead, God in Darwin's mind was unknowable and out of this epistemic certainly all God talk was essentially nonsense.
As Flint points out, this amounts to substantive atheism, agnostic atheism. It seems fair to say Darwin crafted a theory in his own image.