“Extinguished theologians lie about the cradle of every new science, like the serpents strangled by the infant Hercules.” That is how T.H. Huxley classically expressed the “warfare” theory of the relationship between science and religion. On that theory, science and religion are playing a zero-sum game. One advances at the expense of the other. Eternal and irreconcilable opposites, science and religion only flourish by excluding the other.

A number of contemporary writers, especially some of those associated with the “new atheist” movement, still apparently advocate the “warfare” model of science vs. religion. Professional historians of science, on the other hand, long ago rejected that view as simplistic and myth-ridden. Historians such as Ronald L. Numbers, David C. Lindberg, and Martin J.S. Rudwick have provided a more balanced view. True, science and religion have not always enjoyed a happy and peaceful coexistence either. Professional historians have not replaced the “warfare” model with an equally simplistic model of harmony and mutual benevolence. Neither view would be true to the complexities and nuances of actual history, which is always messy and always resists facile categorization. Allow me to recommend the following volumes edited or written by professional historians of science that provide an antidote to the “warfare” model:

God and Nature: Historical Essays on the Encounter between Christianity and Science, edited by David C. Lindberg and Ronald L. Numbers. The University of California Press.

When Science and Christianity Meet, also edited by Lindberg and Numbers, Chicago University Press.

Earth’s Deep History: How it was Discovered and why it Matters, by Martin J.S. Rudwick, University of Chicago Press.

As I say, though, it is far too sanguine to think that science and religion have not conflicted in the past and will not in the future. Andrew Dickson White, writing in the 1890s hoped that the conflict between theology and science was over, but it is not and will not be in the foreseeable future. Here I would like to mention some ways that science and religion still are at least potentially at odds.

1) Evolution. What? Haven’t mainstream denominations all accepted evolution? Did not John Paul II declare that evolution was “more than just a theory,” that is, that it is settled science? Isn’t it just a fringe of fundamentalists and cranks that continue to beat the drum for creationism and its dressed-up cousin “intelligent design?” Well, most religious bodies may have reconciled themselves to some aspects and implications of evolutionary theory. Only Ken Ham and his ilk worry about fitting dinosaurs onto the Ark or squeezing earth history into 6000 years. But, as Daniel Dennett observed, Darwinism is universal acid; it has implications that threaten to eat through many ideologies, both sacred and secular.

            The most radical implication of evolution is not that humans are descended from non-human ancestors or that the Genesis scale for earth history is off by six orders of magnitude. The most disturbing consequence is that humans were not intended. There is nothing in evolutionary theory that indicates that human beings, or any other species, was in any sense fated to be or somehow “in the cards” all along. A core principle of Darwinism is that organic variation occurs independently of the survival requirements of organisms. However much a shrub growing in a desiccating environment might need a deep tap root to access subsiding ground water, the variations that occur in any generation will not be influenced by that need. If, by chance, such a deep tap root does develop in members of that species, then there will be strong selective advantage for such individuals. If the requisite adaptation does not occur, the species will likely go extinct in that region. Nature “intends” neither the survival nor the extinction of that species. The processes that impose environmental challenges and the processes that govern organic variation occur independently of each other.

The upshot is that evolution is a highly contingent process. Environments impose many different kinds of problems and organisms respond with many different kinds of solutions. Which solution will arise to work in a given environment—or if any will—is not something foreseeable. Shit happens. One day you are a Tyrannosaurus living it up in the latest Cretaceous, snacking on Edmontosaurs, and having a good time, when—BANG!—the asteroid hits. Hasta la vista dinosaurs; hola mammal diversification! As if the ordinary chanciness of the evolutionary process were not enough, occasionally mass extinctions reboot the whole ecosystem. Had the K/T event, whatever it was, not occurred, then there would not have been the extraordinary diversification of mammals, and we would almost certainly not be here.

So, what happened was this: A few million years ago a particular species of primate, one not special in any way, chanced upon bipedality as the solution to its environmental problems. Its descendants, equally accidentally, added big brains to the mix. These were not the only solutions possible, and extinction was a definite danger all along. We are damn lucky to be here. We were no more meant to be here than the tufted titmouse or the spiny anteater. Big brains is one solution to life’s challenges. Many, many more are possible, and we do not even know if big brains will be adaptive in the long run. I would place my bets with the cockroach. They were here 250 million years before we were, and my bet is that they will be here 250 million years after we are gone.

For every religion, humans are central to the purpose of the cosmos. We WERE meant to be here. A history of the earth without humans would have been like Hamlet without the brooding prince or Moby Dick without the obsessed Ahab. The story would be radically incomplete, indeed incoherent and incomprehensible. Religious apologists have denied that their doctrine is “anthropocentric,” and have asserted that it is “theocentric” instead. That is, God is the main character, not us. But what would God be without intelligent creatures to know and worship him? What good would it be to be God among the bees, oak trees, and crocodiles that know you not and have no free will to offer in response to your love? Defenders of design arguments take it for granted that the world was designed for us. Indeed, all of those finely-tuned constants are there in order to allow for complex, intelligent life (i.e. us). The God worshipped by Christians would not be satisfied with, e.g. turtles; it had to be us.

Surely, then, for the religious it must be unsettling, to say the least, to be told that we were not meant to be and that, so far as the best science informs us, we are indeed a cosmic accident. Nothing, absolutely nothing, in what we know about the development of the earth and its biosphere indicates that there is anything special about us or that we were “meant” or “intended” in any way at all. Our existence as a species is just as much a product of luck as the existence of each of us as individuals. So, yes, evolution and religion can still clash.

2) Neuroscience. What will happen to you if you ingest 250 micrograms of lysergic acid diethylamide? You will experience vivid hallucinations and extraordinary distortions of perception and awareness. After taking a few such “trips,” you will quit your job at Harvard, move to Haight-Ashbury, grow your hair out, take the name “Moonflower,” go to love-ins and be-ins, listen to Cream and The Dead, and…Oh, sorry, I was having a flashback to 1967. Anyway, we now have overwhelming evidence that anything that changes your brain changes you.

The books of the late, great Oliver Sacks, such as The Man who Mistook his Wife for a Hat, and An Anthropologist on Mars, show in sometimes amusing and sometimes disturbing detail just how disruptions of brain function can alter what we consider the most fundamental aspects of ourselves. We might become convinced that our closest loved ones are strangers, though we admit that they look and act just like our friends and relatives. We might come to feel that an arm or leg, or a whole side our bodies, does not belong to us. We might stop seeing the world in color, and have a hard time eating when we see our favorite foods as disgusting shades of gray.

Has neuroscience proven that all mental function is caused by, reducible to, or realized in brain functions? Has science proven that there is no soul? Well, insofar as a soul is a metaphysical entity, perhaps science cannot disprove its existence. However, as Owen Flanagan notes (The Problem of the Soul) it is at least a regulative idea—a guiding principle—of neuroscience that we think, feel, will, desire, perceive, and do all other mental activities with our brains. That is a basic heuristic or methodological assumption of all brain science. The upshot is that minds and souls, as incorporeal substances a lá Descartes, have no place and play no role in one of the most rapidly growing and productive of the natural sciences.

In general, when naturalistic hypotheses displace supernatural ones, they do not do so by proving the supernatural hypotheses false. They do so by making them useless. The neuroscientist can say of the soul, as Laplace did when asked by Napoleon where God fits into his celestial mechanics, “I have no need of that hypothesis.” Further, souls bring with them quite a bit of troublesome baggage. They make us ask uncomfortable questions like this: At what point in evolutionary history, or where in present day nature, does mentality require a soul? If humans must have a soul, what about bonobos, or monkeys, or cats, or crocodiles, or oysters? Did Australopithecus have a soul, what about Homo habilis? Homo erectus? Homo ergaster? Neanderthals? Cro-Magnons? Just where in the natural world, or in evolutionary history, do we drive the golden spike to indicate where brains are no longer sufficient and a soul is required? There seems to be no non-arbitrary answer to this question.

The most inconvenient baggage of the soul-hypothesis is the one it has been carrying all along: How do we conceive of interactions between soul and body? That question was first posed to Descartes by Princess Elizabeth of Bohemia, and it has not—and cannot—be answered. As Flanagan notes, a Cartesian dualist must bite the bullet and say that mind influences matter by a kind of psychokinesis. Of course, this bullet can be bitten, and dualists can just live with it. It does, however, unquestionably complicate worldviews to add spiritual entities with occult powers of interaction, and surely we should not so blatantly violate Ockham’s razor without a very good reason. Can dualists offer such a reason? Here I simply refer the reader the “Great Debate” between Andrew Melnyk and the Christian philosophers Stewart Goetz and Charles Taliafero posted in the Modern Library of the Secular Web. Melnyk defends a physicalist view of mind and Goetz and Taliafero defend substance dualism. In my not-so-humble opinion, Melnyk wins hands down. Read Chapter Eight of my book It Started with Copernicus for my complete presentation and evaluation of this debate.

Religion, however, seems to need souls. They are explicitly included in the ontologies of many religions. Krishna assures Arjuna in the Bhagavad-Gita that the body is not the reality, but the soul, and that in killing the body you only destroy the wrapper, not the goodie inside. Further, as Goetz and Taliafero note, without souls it becomes very hard to maintain some things that are very important to many religions. Obviously, there is the afterlife. If not the soul, what survives death? Some might say that the Christian doctrine is one of resurrection, not survival. However, the resurrection hypothesis raises deep conundrums about personal identity. Once the person is utterly destroyed, say vaporized in a nuclear explosion, how could a simulacrum, even one endowed with the memories of the original, be the same being? A continuously conscious soul, or something like it, would seem to be required to maintain the sort of continuity required for a continuous personal identity. If I ceased to exist, what would be the point in creating another just like me—but not me—to go to heaven or hell?

Further, as Goetz and Taliafero argue, a soul seems to be required for libertarian free will. If we are to be held responsible by God for our lives, and appropriately rewarded or punished in the afterlife, surely WE must be fully responsible for all of our good and bad choices. Determinism, even “soft” determinism, seems incompatible with eternal rewards and punishments based upon our supposedly free choices. If we choose with our brains, however, it is hard to see how those choices are not determined. The brain is a physical system and as subject as any other such physical system—a computer, say—to physical determination by electrical and chemical causes. Sending people to postmortem punishment (or reward) because of what their brains did does not seem a fair or just proposition. Neuroscience would explain why some people believe, and so accept grace, and some people do not.

It appears, then, that there are also at least potential clashes between neuroscience and religion. Maybe the relation between science and religion is not one of constant warfare, but the occasional street brawl will still occur.