Does Evil Exist?

Or Is Your Conscience Just a Survival Strategy?

Moral Knowledge

It begins with something you do every day without noticing. You trust your own moral judgments. You don’t merely feel that egregious acts of cruelty committed for fun are wrong. You believe it to be objectively true. You think you genuinely know it, with the same confidence you bring to knowing that gratuitous suffering is bad, that the Holocaust was evil, that something about human beings makes them worth more than furniture. That confidence feels obvious. Foundational, even. But here is what almost nobody stops to ask: How is that confidence even possible?

Shifting the Question

Let’s grant, just for the sake of argument, that objective moral truths exist. Let’s grant that it really is true, independently of what anyone thinks, that torturing the innocent and vulnerable for amusement is wrong, that committing atrocities against children is objectively wrong, regardless of anyone’s view about it. The question I want to press is different and, I think, deeper: Why should we believe that beings like us, products of blind evolutionary forces, have any reliable access to those truths? Why assume that our moral faculties are aimed at moral truth, rather than merely at genetic survival?

What Evolution Actually Selects For

If naturalism is true – the philosophical view that the physical universe is all there is – we are the unintended products of a blind process, one that cares about truth only when it happens to coincide with genetic survival. Our brains were shaped by billions of years of natural selection. And natural selection selects for one thing: fitness to survive. It does not select for truth, though sometimes truth and fitness coincide.

Accurate beliefs about predators, food, and social dynamics can confer survival advantages. A prehistoric human who correctly believed that the lion was dangerous had good reason to run. But evolution selects behaviour, not accuracy. And false beliefs can produce adaptive behaviour just as reliably as true ones. If a prehistoric human believed “that lion is a demon sent to punish sinners”, the belief may be false, but if it produces the same behavioural response, natural selection doesn’t care. The filter is whether you survive and reproduce, not whether your beliefs correspond to reality.

This becomes acute when we leave immediately practical beliefs and enter abstract territory: mathematics, logic, metaphysics, and of course, ethics. What reason is there, on naturalism, to think that what has shaped for survival has been calibrated to track abstract moral truth? The evolutionary story is a story about fitness. The moral story, if moral truths exist, is a story about something else entirely. On what grounds do we assume they converge?

The Philosopher’s Dilemma

Philosopher Sharon Street sharpened this problem into what she calls a Darwinian dilemma. Her 2006 paper is one of the most discussed pieces in contemporary metaethics, and for good reason: it forces a choice that is genuinely uncomfortable. If objective moral truths exist, independent of human attitudes, out there to be known, then those truths are causally inert. They don’t push atoms. They don’t guide DNA replication. They exert no selection pressure on evolving populations.  

Meanwhile, our moral intuitions arose because they enhanced cooperation, kin loyalty, punishment of defectors, and group cohesion; exactly the behaviours that enhanced fitness in ancestral environments. People evolved to care about their children, their tribe, their social standing. We evolved disgust at certain violations. We evolved rough-and-ready notions of fairness.

This gives us two independent narratives running in parallel:

• Narrative One: what is actually right and wrong, as a matter of objective moral reality.

• Narrative Two: what our ancestors were shaped to believe by selection pressures that tracked fitness, not truth.

Street’s dilemma is that either these two narratives are connected, or they are not.

• If they are not connected, then most of our moral beliefs are probably off track, distortions produced by fitness-enhancing pressures that have nothing to do with moral truth. That is radical moral scepticism, which most people find intolerable.

• If they are connected, if evolution somehow tracked moral truth, you owe a scientific explanation for how that happened. But moral truths are causally inert. Any account of how evolution “tracked” abstract moral facts faces insuperable scientific problems.

Either horn of the dilemma is damaging. If human cognition is ultimately designed to track moral truth, neither horn applies. The connection between our moral faculties and moral reality is not a coincidence; it is a feature of the design.

The Coincidence at the Heart of Naturalism

Imagine a vast matrix. Across the top axis: every possible moral system that could be objectively true. Down the side: every possible moral psychology that evolution could have installed in creatures like us for survival reasons.

For human beings to possess genuine moral knowledge, we must inhabit a cell in that matrix where the moral system that is true happens to be the one that evolution gave us. But natural selection is blind to moral truth.

If ruthless dominance had maximised genetic survival in our evolutionary past, we might have evolved to revere cruelty. If rigid hive-like obedience had been optimal, we might have evolved to regard individual dignity as a dangerous illusion. The specific content of our moral beliefs would simply track what was adaptive, not what is true.

And yet here we are, confidently proclaiming that cruelty is wrong and human beings have inherent worth. If those judgments are genuinely true, and if we arrived at them through a process indifferent to truth, the coincidence is staggering. Under theism, there is no coincidence. The fit between conscience and moral truth is expected; it is the whole point.

Plantinga’s Escalation

Here the problem deepens. Alvin Plantinga’s Evolutionary Argument Against Naturalism presses a still more radical version of this worry. The concern isn’t just about moral knowledge; it’s about all knowledge.

Plantinga’s argument turns on what he calls warrant, the property that converts true belief into genuine knowledge. A belief has warrant, on his account, only when it results from cognitive faculties functioning properly according to a design plan successfully aimed at truth. Under naturalism, our cognitive faculties have no design plan aimed at truth. They were shaped by processes aimed at fitness. The probability that these faculties would reliably track truth in abstract domains, rather than merely producing adaptive outputs, is astonishingly low.

If that is right, the trouble isn’t confined to ethics. It extends to every domain where our faculties venture beyond immediate practical necessity: higher mathematics, quantum mechanics, modal logic, metaphysical reasoning about the nature of naturalism itself.

This self-undermining quality is the sharpest edge of the argument. If naturalism is true and our faculties are unreliable trackers of abstract truth, then the very beliefs that led us to accept naturalism are themselves suspect. The naturalist who deploys rational argument to defend naturalism is using faculties whose reliability they have no right to assume.

C.S. Lewis saw this clearly in Miracles: if mental processes are determined wholly by non-rational causes, there is no reason to suppose they yield valid results. Naturalism, pushed to its logical conclusion, saws off the branch it is sitting on.

Dissolving Morality

A sophisticated secular defence comes from Erik Wielenberg in Robust Ethics. His solution to the coincidence problem relies on what he calls a “third factor”—essentially, a package deal. He argues that the moment evolution produced creatures with advanced cognitive abilities who can reason and suffer, objective moral facts (like “it is wrong to torture these creatures”) automatically sprang into existence. Think of it like drawing a triangle: you might just set out to draw three connected lines, but the moment you do, it becomes an unavoidable, objective fact that the interior angles add up to 180°.

In this view, the physical and mental traits evolution gave us automatically ground our moral reality. Yet, Wielenberg himself admits that there is one worldview that requires “much less luck” for moral knowledge than his own: “our old friend theism”.

Even more pertinently, perhaps, critics channelling Plantinga point to what they see as a deeper flaw in Wielenberg’s escape route. He is still using an evolved, survival-oriented brain to declare that his evolved, survival-oriented brain is flawlessly perceiving these abstract, philosophical truths. Ultimately, he inherits the full force of the reliability problem. Still, such defences warrant serious consideration.

Meanwhile, Sharon Street’s own preferred response to her dilemma is to abandon moral realism altogether and embrace anti-realism: there are no mind-independent moral truths, only evaluative attitudes instilled in us by evolution. This dissolves the coincidence problem elegantly. But it dissolves it by dissolving morality.

On Street’s view, when you say the Holocaust was genuinely evil, you are not stating anything objectively true. You are expressing a deeply held evaluative attitude, one evolution helped install, with no claim to truth-tracking status. Most people find this conclusion intolerable. And the fact that it represents the most internally consistent naturalist solution to the problem is itself evidence about the nature of the problem.

The Universal Grammar of Conscience

There is one further dimension worth drawing out. If our moral beliefs were simply shaped by local adaptive pressures, we would perhaps expect far more fragmentation. Evolutionary game theory does predict that selection would produce overlapping cooperative norms across populations—fair exchange, kin altruism, punishment of defectors. True. But this does not explain the full moral grammar, including the persistent intuition that some things are wrong even when you could get away with them entirely.

Even if evolutionary psychologists point to mechanisms like costly signalling or group selection to explain deep-seated altruism, these theories only explain the existence of our behavioural urges, not their objective moral authority. Under theism, that explanation is natural. Under naturalism, the convergence seems harder to explain on its own terms.

What This Argument Actually Establishes

Let me be precise about what follows from all of this, and what does not.

• It does not reject the scientific theory of evolution. The biological reality of natural selection is not the target here. The question is not whether evolution happened, but whether a purely blind, unguided evolutionary process can account for objective moral knowledge.

• It does not claim that atheists cannot behave morally. They obviously can and often do so with admirable consistency.

• It does not claim that evolutionary psychology explains nothing about moral psychology. It explains a great deal, including why our moral instincts are sometimes unreliable or tribally distorted.

• It does not claim that naturalism is logically impossible or strictly self-refuting in a single step. What it claims is a comparative epistemological point: If naturalism is true, the reliability of our moral cognition, its status as genuine knowledge rather than adaptive illusion, is epistemically fragile and ultimately inexplicable. If theism is true, that reliability is expected, grounded, and makes perfect sense.

We are comparing explanatory frameworks. Theism predicts that human moral cognition tracks moral truth. Naturalism makes that alignment an unlikely coincidence or requires accepting that we don’t actually have moral knowledge at all. When we discover that virtually everyone is deeply committed to the reliability of their moral faculties, that widespread commitment itself functions as evidence about which framework is right.

The Hidden Wager in Your Own Life

Here is what strikes me most about this argument. Everyone who engages in moral reasoning is already wagering that their moral faculties track reality. When you condemn an act of genocide, you are not merely reporting your preferences. You are making a claim about what is true. When you admire courage or deplore cruelty, you are implicitly asserting that your judgment connects to something real.

That wager is not neutral. It presupposes that your mind is oriented towards moral truth rather than merely towards survival. It presupposes something like proper function in Plantinga’s sense; that your conscience is working as it is supposed to work, tracking what it was built to track.

The Quiet Turning Point

The argument from moral knowledge doesn’t ask you to abandon reason. It asks you to follow reason honestly; past the question of whether moral truths exist, all the way to the question of what kind of universe must be true for moral knowledge to be possible at all. If we were made only to survive, our deepest moral convictions may be nothing more than fitness-enhancing shadows cast on the wall by natural selection. Beautiful, perhaps. Useful. But not knowledge. If we were made for truth, then the fact that we reach for justice, recoil from cruelty, and perceive the dignity of persons is exactly what we should expect. Not a coincidence. Not an accident. A sign.

In this sense, the most natural explanation of moral knowledge is perhaps that we were made to know.