04/26/2012 11:41 am ET Updated Jun 25, 2012

The Natural Selection of the Immortal Soul: A Thought Experiment

Note: These are the first three parts of a nine-part essay that I hope to post over the next week or so.

I. Darwin's Ghost

Of late, Darwinism has invaded nearly every domain on earth and some well beyond. Neurology, immunology, medicine, even cosmology: one field after another has trembled beneath the tread of those hobnailed Victorian boots.

The process by which you read these lines arises, we're told, from a struggle between competing neurons. Disease is seen an adaptive balancing act, or as an awkward entente between two species, pathogen and host. The universe itself may be the hardy survivor of a process of natural selection in which trillions of universes have been winnowed and cast to the winds.

All of which is natural enough if natural selection is indeed, as Daniel Dennett claims, "the single best idea anyone has ever had."

One domain, however, has remained off limits.

It is this domain that Darwinism, in its early hooligan days, threatened not simply to invade but to annihilate (Charles's own assurances notwithstanding). For the stakes in the great dust-ups between Huxley and Wilberforce, Darrow and Bryan, and countless lesser-known combatants were not just our origins, but our end. Monkey-as-uncle stuff may muss our pride -- the paragon of animals felled by a banana peel -- but Darwin's real threat was to our hope. If we are merely animals, then we die like dogs. If we are products of blind chance, rather than the dandled darlings of a grandfatherly god, then our consciousness, too, must go the way of all flesh.

Not the dust we come from, but the dust we go to, fills us with dread.

The Age of Spiritualism -- that late-19th and early-20th-century explosion of mediums and seances, of apports and apparitions, of ectoplasm captured on glass photographic plates -- has been seen by historians as a desperate attempt to shield the immortal soul from Darwinian assault. Twenty-first-century Creationists, at whose behest evolution is demoted in public high-school textbooks to the level of wild speculation, seem to be adopting the same protective crouch.

How, I wonder, would they react if someone were to suggest that the survival of the soul after death, far from being ruled out by the theory of natural selection, might actually be predicted as a consequence of that theory?

I am suggesting exactly that.

Note that I am not claiming that we survive after death: on that point I am a devout agnostic. My claim is rather that, from a Darwinian perspective, it would not be wholly surprising if we did. Conversely, if, for whatever reason, one came to believe that survival after death were a fact, natural selection would be one plausible explanation. It turns out to be a plausible explanation, as well, for any number of other things one may or may not believe in: angels, demons, interceding saints and tzaddiks, saviors and messiahs, heavens, hells, even gods.

All these plurals I use deliberately. For the Darwinian framework I use here suggests the possibility that the religious beliefs of all peoples on earth may be simultaneously true. True, I mean, not in their moral or mystical essence -- the "many paths lead to the mountain" or "we are all children of God" sort of thing that enlightened people nowadays mouth quite automatically -- but in their most minute particulars. True, however, only for certain groups of people, at certain times (which is why, two sentences back, "simultaneously" is not quite the word I want).

II: The Thesis

Bearing in mind that this is a thought experiment, let's experiment with the following thought: From the point of view of Darwinian logic, survival after death is no more surprising than survival after menopause.

Survival after menopause is surprising, though we take it for granted. (The problem mainly concerns women, of course, but arises -- or, more crudely, fails to arise -- for men as well.) If evolution has shaped us, like all creatures, to maximize our reproductive success, why do we stick around past reproductive age? From a Darwinian standpoint, it doesn't seem to do us any good; it might even do us harm, if we use up resources that might otherwise go to our offspring and help them reproduce. This would seem to be particularly true in the sort of small hunter-gatherer band in which most of human evolution presumably occurred.

Faced with this conundrum, Darwinians have offered two answers.

The first is to remind us that natural selection works in a rough-and-ready way, cobbling its devices together from the materials at hand. (Though Aristotle says there is no waste in nature, the truth is that waste, excess and redundancy are central to her mode of operation.) To reproduce successfully a creature must first of all survive and remain healthy through reproductive age, which in humans is fairly late. Such a creature must be programmed for self-perservation. And a creature programmed for self-preservation is, to a degree, a machine that will go of itself.

There are, of course, creatures that are programmed to self-destruct, more or less, when their reproductive job is done. Some even pay for reproduction with their lives. But these are creatures that do not have much of a role to play in the lives of their offspring. They toss them into the world and let them fend for themselves. Humans, by contrast, continue to invest in their offspring for many years after begetting or bearing them.

Which brings us to the second explanation.

In a wide range of human societies, parents can be useful to their children long after they are grown (though the children may not like to admit this). Even when parents are so elderly that they appear to be a burden, the benefit of their experience may be considerable. Again, this would be especially true in the hunter-gatherer context, where there are no libraries or websites to rely on and the memory of a patch of melons, stumbled upon years earlier during a draught like the present one, may spell the difference between life and death.

If survival after death were, like survival after reproductive age, a known fact, it might be accounted for in roughly the same ways. Thus we might say that the mind, or the soul -- a form of consciousness that appears to have adaptive value, and that is robust enough to survive the constant turnover of the protoplasm on which it seems to depend -- might also be robust enough to survive the loss of that protoplasm. Might, in other words, be a machine that goes of itself, even after its hardware is trashed.

This, admittedly, is a fairly lame explanation. Luckily the other is a good deal stronger.

III. The Immortality Gene

The folklore of most known cultures, as well as the reports collected by modern researchers, suggest that spirits, when they appear to the living or take a hand in their affairs, do not do so arbitrarily. They have an agenda. More often than not, that agenda is to provide aid or comfort to their descendants.

If human beings can be aided not only by elderly relatives, but by dead ones, than survival after death would be just as explicable, in Darwinian terms, as survival after menopause.

Of course, it may seem odd to be explaining a fact that is not known to be a fact. So let us approach the matter from a slightly different angle.

Suppose that, at some point in the history of the species, a mutation arose which allowed an individual's mind to persist after the body's death. Suppose further that there was some way for that mind to confer benefits upon its earthly offspring. Suppose, finally, that this mutation was genetically transmitted to these offspring (or at least to some of them). It seems likely that these offspring would have a competitive advantage over their neighbors, and would reproduce more successfully -- especially since they, too, would be able to assist their own offspring after they themselves had died.

As this pattern repeated itself, the gene or set of genes enabling the mind to survive the body's death -- the immortality gene, so to speak -- would spread through the population. In time it might become standard equipment, as universal as language or laughter.

At this point the vigilant reader will object that the ability to fly, deflect bullets and see through walls would presumably have selective value, yet this does not prove that Superman exists. Let me repeat: I am not arguing that an afterlife exists, only that, from a Darwinian point of view, it would not be surprising if it did. Still, it's only fair to say that the evidence for the existence of an afterlife, weak though it may be, is a good deal stronger than the evidence for the existence of Superman. (For what it's worth, a recent Gallup poll found that a majority of America's bereaved report having been visited by their lost loved ones; surveys in Wales, Iceland and elsewhere yield similar results.)

Now, the fine print: when I call the soul immortal, I do not mean that it lives forever (though it might). I mean only that it doesn't die when the body does. Darwinian logic supports the latter, not the former. Survival of the soul for decades, perhaps a century, would confer selective advantage, but after a few generations one's genes would be so diluted in one's descendants that helping them might hardly be worth the bother.

Psychics and wisdom traditions speak of the dead "moving on" after a time (40 years being one common figure). Do the dead just fade away, like embers in a fireplace that outlast the logs but then, at length, go cold? Or do they decamp for another realm and enjoy life eternal, quite indifferent to the question of whether their great-great-grandaughter gets into Yale?

If, by some mutation or other, a soul arose that was robust enough to survive death, perhaps it really would live forever (as Mme. du Deffand said of the decapitated St. Denis's famous six-mile walk, head in hand: "It's only the first step that's difficult"). True, it's hard to imagine what physical or energetic or informational medium could harbor a soul robust enough to survive the heat death of the universe or its collapse and rebirth in a new Big Bang. But here our earthbound notion of time may be leading us astray. It could be that eternity, once you've found your way into it, is safely removed from such petty mishaps, being apart from time rather than simply a lot of it.

Next: Wishful Thinking?