In a podcast arranged to coincide with the publication of my Taking Leave of Darwin one listener enquired (with a hint of courteous reproach) why I had thought it relevant to delve back into the era of philosophers from classical antiquity to clarify the work of a 19th-century naturalist. Standing my ground, I replied that, although not all would suspect it, Charles Darwin's ideas, with their ancient (and often overlooked) origins stretching back at least three millennia, were in the last analysis derivative rather than original. At the very least, I conceded, Darwin's ideas may have arisen in a way anthropologists term "polygenetically" -- meaning that similar ideas can arise spontaneously and independently in different times and cultures the world over even though those disparate cultures have experienced no direct cultural contacts with one another.

Long after that interview, on further pondering the implications of my podcast questioner's query, I began to suspect that Darwinism was being presented and taught at school level in a somewhat philosophically decontextualized way lacking historical background. I have to confess that in my own case I remember learning about Darwin as an historical fact rather like the Battle of Hastings or the American Revolution. There was as little debate about Darwin as there was about the identity of the man who won the long jump at the Mexico Olympics of 1968 (Bob Beamon). No hint was given of the centuries-long, perennially contested intellectual hinterland which lay behind Darwin as he put pen to paper on his celebrated opus in 1859. In the case of my own schooling at any rate, I came away with the distinct impression that Darwin (together with Alfred Russel Wallace) all of a sudden came upon an unheralded, revolutionary and literally world-shattering idea right there and then in the middle years of the 19th century.

I also made the erroneous inference that evolution itself (the intellectual focus of Charles's grandfather, Erasmus, in the preceding century) was also Charles's idea. It was only much later in life that I realized, to use the metaphor of historian Simon Schama, that Charles's contribution represented only the final "consummation" of a longer debate about human origins. Having come to that belated recognition, and staying for a moment with Schama's metaphor, I was reminded of a light-hearted remark once made by my late mother to the effect that "every new generation thinks it has invented sex." Or to put the matter in the more formal terms of a Cambridge classicist, Tim Whitmarsh, it is only the pedagogical neglect of our ancient classical heritage that has allowed a "modernist mythology" to take hold. This way of thinking has led to the fallacy that 18th- and 19th-century Europeans were the first to ponder evolutionary matters. Of course the precise opposite is the case: Erasmus Darwin himself was the legatee of a millennia-old constellation of speculation concerning cosmogenic origins.

The story of the ancient Greek and Roman precursors of modern evolutionary thought has been told far too many times to be rehearsed here. It is now well enough known that, long before Darwin walked this earth, ancient thinkers had speculated that plants and animals had simply "evolved" via an extended process of trial-and-error reminiscent of what Darwin would later term natural selection. In some cases the animal's evolutionary journey had been unsuccessful, went the ancient contention, resulting in creatures not properly equipped to compete for resources or to produce offspring (what farmers refer to as "runts"). Such creatures were destined to extinction, in contradistinction to vigorous and perfectly formed specimens able to adapt and reproduce.

But what has not been so frequently noticed is the historiographical bias commonly accompanying the telling of such accounts. For the similarities of Darwinian ideas shown by ancient thinkers has invariably been glossed and framed as a narrative of progressive revelation in which tentative and unscientifically unattested speculations from such as Empedocles, Epicurus (pictured at the top), and Lucretius came at long last to be validated by naturalists in the post-Enlightenment world -- pre-eminently by Charles Darwin. But that mode of history-telling is partial and one-sided since what is not routinely adverted to is how controversial these ancient ideas originally were and have continued to be throughout recorded history. Some objections, to be sure, arose on religious grounds but many other philosophical dissenters, arguing from reason alone, opposed the case of the materialist philosophers because they represented an obstacle to logical cogency and even simple common sense.

Epicurus and his Roman follower, Lucretius, for instance, also taught that the answer to the world's supremely complex evolutionary processes was to be sought not in a once-and-for-all divine creation but in different shapes and objects generated at random by the chance interaction of atoms. Such appeals to serendipity/natural selection were argued over just as much in the classical world as in the era post-1859. Materialist philosophers in antiquity found themselves pitted against the teleological evidences of celebrated philosophers like Plato and Aristotle who espoused the belief in a creative mind (nous) and an original Unmoved Mover -- the conception later endorsed by Thomas Aquinas in the Middle Ages and incorporated into Christian theology.

For Aquinas the only sensible consensus on logical grounds was that there must be some unitary source of all things. This for him was not even primarily a religious matter: it was by no means necessary to be an adherent of the Judeo-Christian tradition to accept the idea, he stated. The pioneering medical authority of the early Christian centuries, Galen, had also had little but derision for the atomist thinkers. For him, those philosophers' unqualified exclusion of divine causation left nature stranded and unintelligible. Even though members of the atomist school were wont to cover themselves by appealing to the power of endless time and space, they were still obliged to postulate accidents of fate on a risibly vast scale, asserted Galen in a logical objection which clearly still contains a powerful reproach to modern acolytes of Darwinian speculation. Of all ancient authors it was perhaps surprisingly the jurist Cicero who put the objection to the materialist position in the most forensically trenchant terms,

Does it not deserve amazement on my part that there should be anyone who can persuade himself that certain solid and indivisible bodies travel through the force of their own weight, and that by an accidental combination of these bodies a world of the utmost beauty and splendour is created? I do not see why the person who supposes this can happen does not also believe it possible that if infinitely many exemplars of the twenty-one letters of the alphabet, in gold or in any material you like, were thrown into a container then shaken onto the ground, they might form a readable copy of the Annals of Ennius [a now lost Roman history]. I'm not sure that luck could manage this to the extent of a single letter.

David Sedley adduces the Ciceronian passage as the best riposte to that silliest of modern canards to the effect that a monkey at a typewriter, given infinite time, might produce the works of Shakespeare -- the same idea that Sir Fred Hoyle (anticipating Michael Behe and many others) dismantled most memorably when he wrote:

A generation or more ago a profound disservice was done to popular thought by the notion that a horde of monkeys thumping away on typewriters could eventually arrive at the plays of Shakespeare. This is wrong, so wrong that one has to wonder how it came to be broadcast so widely. The answer is I think that scientists wanted to believe that anything at all, even the origin of life, could happen by chance, if only chance operated on a big enough scale.... The striking point is that the only practicable way for the Universe to produce the plays of Shakespeare was through the existence of life producing Shakespeare himself. Despite this, the entire structure of orthodox biology still holds that life arose at random. Yet as biochemists discover more and more about the awesome complexity of life, it is apparent that the chances of it originating by accident are so minute that they can be completely ruled out. Life cannot have arisen by chance.

Hoyle himself for all his brilliance did not always remain immune to quite literally outlandish ideas such as "panspermia" (the theory that life was seeded on Earth from somewhere in outer space); but surely his contention that "Life cannot have arisen by chance" must remain indisputably compelling.

With the benefit of much historical hindsight, it would be theoretically possible to make a (somewhat labored) case that the upshot of philosophical speculation going back millennia was to give the modern world a simple binary choice: either Epicurus/Lucretius or Galen/Aquinas. Darwin in effect chose the Lucretian model which would come to challenge the Aristotelian/Christian conception of an ultimate (divine) reality, at least for certain sections of the intellectual classes. However, we know more than enough about the much-documented Victorian crisis of faith to realize that Darwin's Origin of Species did not recommend itself so much on the basis of its scientific or philosophic merits (which of course were empirically ungrounded and unfalsifiable in the Popperian sense) but rather as a de facto vote of no confidence in Biblical accounts of creation allied to a progressive erosion of traditional modes of faith. Hence when Darwin wrote of natural processes in contradistinction to divine modes of creation, he was pushing at an open door because his audience wanted to believe him.

There is also some truth in that contention but Darwin also possessed in his persuasive repertoire a factor which has not gained so much attention. This concerns his attempt to imply to his readers that his theory was not ancient but derived from his up-to-date researches in what we now term the social sciences. Just to recapitulate: the following was Darwin's much-cited report of his reading of economist Thomas Malthus on human populations:

Favourable variations would tend to be preserved, and unfavourable ones to be destroyed. The results of this would be the formation of a new species. Here, then, I had at last got a theory by which to work [...] I saw, on reading Malthus on population, that natural selection was the inevitable result of the rapid increase of all organic beings [...Malthus] gave me the long-sought clue to the effective agent in the evolution of organic species.

As is well known now, Darwin's appeal to Malthus was something of a non sequitur or tautology and many of the leading lights of the 19th century refused to be impressed by Darwin's appeal to the leading social scientist of his age.

But what such bemused commentators as Darwin's son, along with Friedrich Engels and others, did not fully comprehend was that what interested Darwin was in good part the chance to co-opt the respected demographer to give an all-important scientific patina to his ideas. The deep antiquity of those ideas could be effectively camouflaged by deflecting readers' attention towards the testimony of the modern economist and demographer.

The trompe l'oeil worked, and the result has been that the ancient voices of Epicurus and Lucretius, whose resonance in antiquity right up to just beyond the middle of the 19th century was despised, have since that time been successfully smuggled into our collective consciousness thanks to the sometimes-covert appropriations of modern mediators. The atomistic philosophy has essentially been co-opted and adapted for consumption by the modern world on the back of the Darwinian hypothesis of natural selection. As Matt Ridley noted, "More than two thousand years ago Epicureans like Lucretius seem to have cottoned on to the power of natural selection [...] Darwin was rediscovering an idea."

Rightly or wrongly Darwin had somehow succeeded in justifying what had been previously been either roundly mocked or else execrated, and to such an extent that historians Stephen Greenblatt and Matt Ridley have seriously proposed that Lucretius's De Rerum Natura "could serve as an agenda for modernity." Remarkably, beginning in the final decades of the 19th century, the atomistic philosophy that Aristotle, Plato, Cicero, Galen, and a host of further distinguished thinkers in many later centuries had long since denounced for its manifest absurdity was now, Phoenix-like, rising from the ashes to which it had been relegated by the leading thinkers of the early Western tradition for well over a thousand years. It is surely a remarkable turn of historical events that a doctrine once widely adjudged borderline-insane should have won the status of the explanatory master narrative of our advanced technological societies appealed to by biologists and cosmologists alike.