by Lewis Vaughn
Some atheists reject objective morality, or any kind of morality, for the same reason that the atheist philosopher Jean-Paul Sartre did—they believe that if there is no God, everything is permitted. That is, morality requires a God who makes it, a God who is the author of the moral law, and since there is no God, there is no morality. This notion about the source of morality is known as the divine command theory, and both atheists and theists have assumed it. But it does not follow from the nonexistence of God that there are no moral truths, and the divine command theory itself has been shown to be radically implausible—which is why even many theists won’t accept it.
Moral objectivism comes in two main forms: moral naturalism and moral non-naturalism. Moral naturalists believe that moral facts are natural facts—facts that can be investigated and confirmed by science. So there is no mystery about the existence of objective moral truths: science shows that they are as real as frogs and stars. For the moral naturalist, a morally right action is one cashed out in natural terms like “maximizes happiness,” “promotes flourishing,” or “enhances social harmony.” Moral non-naturalism, though, says that moral facts are not natural facts, not the sort of thing that can be detected with a microscope or Geiger counter. They are nevertheless real, the non-naturalist says, and there are good reasons to believe them so.
Moral objectivists of whatever stripe have good reasons for thinking moral truths are objectively real. Philosophers (most of whom are atheists) know that any worthy moral theory must meet one crucial standard—consistency with the fundamental facts of our moral practice and thought, what some call moral common sense. These facts—articulated in our considered moral judgments—are fallible, revisable, and yet highly plausible. And they can constitute credible evidence in our moral deliberations. Philosophers use them not only to formulate moral theories but also to test them for soundness. Common sense tells us, for example, that wantonly killing people is wrong, that equals must be treated equally, that slavery is an abomination, that the execution of gays and atheists is immoral, and that torturing babies for fun is evil. Common sense also reveals that there are such things as moral error and fallibility, genuine moral disagreement, the seeming fact of moral progress, the possibility of legitimately criticizing other cultures, and non-arbitrary moral judgments. We should have more confidence in our judgment that torturing babies is wrong or that moral infallibility is absurd than in any theory that says otherwise. The most devastating criticism of a moral theory we can make is that adhering to its defining principles leads to obviously immoral acts. And if someone denies our considered judgments, the burden of proof is on him or her to supply a good reason for the denial. It is moral common sense that gives the lie to moral nihilism (the view that there are no moral truths) and to moral relativism (the theory that moral standards are not objective but are relative to what individuals or cultures believe). It is moral common sense that helps guide both naturalists and non-naturalists to moral objectivism.
Among atheists, the most important debate is between the two camps of moral objectivists—the naturalists and the non-naturalists. I suspect that most atheists take the naturalist route because they believe in science, and science seems to suggest that if morality exists, it must exist as a natural property of the natural world. They tend to regard moral naturalism as obvious and ineluctable, and they see moral non-naturalism as incredible and suspiciously akin to theistic morality or Platonic forms floating in the ether.
The arguments favoring moral naturalism are impressive (and have been put forth by brilliant thinkers, including David Brink, Judith Jarvis Thomson, and Frank Jackson). The moral naturalist contends that non-naturalistic moral facts don’t exist. They don’t exist, because science cannot prove their existence. In science, something exists only if it explains our experiences. Subatomic particles are thought to exist because they are the best explanation of what scientists observe in experiments. Gremlins don’t exist, because they don’t explain anything. Likewise, the moral naturalist says, non-naturalistic moral facts don’t exist, because they don’t explain anything either. We can point to no empirical facts and honestly affirm that non-naturalistic moral properties best explain those facts. Therefore, such moral properties are purely imaginary.
A related argument appeals to a common assumption about the nature of scientific knowledge. A popular version of it says that a claim is true only if it can be verified scientifically. The belief that smoking causes cancer is true—it has been confirmed in scores of scientific tests. A belief in angels (whether or not they dance on the head of a pin) cannot be scientifically confirmed, so there is no reason to believe in angels. The claim that non-naturalistic moral properties exist cannot be scientifically verified either. Therefore, the argument goes, there is no more reason to believe in these properties than in angels. They are both unreal.
Moral non-naturalists are undeterred by such reasoning. (Among distinguished non-naturalists we can count Derek Parfit, Jonathan Dancy, and Russ Shafer-Landau, whose work inspired some of the points in this essay.) They argue that the burden to show that naturalism is the better moral theory rests on the naturalists, and that the latter have failed to make their case. The default position, the non-naturalists say, is the commonsense view, which is that morality is just what it appears to be—objectively real and distinct from natural properties. This conclusion is bolstered by the plain observation that normative moral truths don’t appear to be at all the same thing as natural states of affairs. The normative concept of moral rightness seems, on its face, not to be identical to any natural fact. And despite many attempts, philosophers who accept moral naturalism have had a difficult time demonstrating any such identities. Too often a natural state of affairs that’s supposed to be identical to moral rightness turns out in some situations to exemplify obvious immorality. Maximizing happiness or minimizing harm, for example, can sometimes conflict with our commonsense ideas about justice and rights. Plausibly identifying our considered moral judgments with physical properties is not easy.
Non-naturalists have also addressed worries about the alleged unreality of non-naturalist moral facts. As just mentioned, moral naturalists insist that such “facts” can’t be real because they aren’t needed to explain objects and events in the real world. But, the non-naturalist says, non-naturalist moral facts don’t have to explain empirical facts, for they aren’t in that line of work. Moral facts are normative facts. They prescribe how things should be, not how they are. They are like another kind of normative facts—epistemic facts, which prescribe what we should believe (like “we should portion our belief to the evidence” or “we should not believe contradictory statements”). Epistemic facts don’t explain anything, but they are nonetheless real, and everyone knows it. If we accept the reality of epistemic norms, there is no reason we should not accept the existence of (non-naturalistic) moral norms.
The non-naturalist can also easily handle the argument about scientific verification. The assumed principle is that no statement is true unless it can be verified by science. This world is naturalistic through and through, with no room for gremlins, angels, and non-naturalistic moral facts. But this principle is false, because it is self-refuting. It is itself a statement that cannot be verified by science, so if the principle is true, it must be false. Therefore, it is not the case that only scientifically confirmed statements are true. There are truths outside the purview of science.
Namely, philosophical truths. The verification principle itself is a philosophical claim. It is through philosophical inquiry that many of the fundamental postulates of science are evaluated and refined—postulates about what the scientific method should entail, what distinguishes good explanations from bad, what justifies scientific knowledge, what entitles us to believe in the truth of scientific theories, whether it is possible to have knowledge of unobservables, and whether scientific theories are true descriptions of an independent reality. (It is, of course, also through philosophy that arguments for the existence of God are demolished.) So there is philosophical knowledge—and as it turns out, ethics is a kind of philosophical knowledge, debated and distilled through logical argument and careful reflection. This process can, and often does, yield justified moral beliefs.
In light of the above arguments, and several others, I side with the non-naturalists. But nothing I’ve said here definitively proves my case. It would take a thousand more posts and several books to do that. Perhaps, though, I’ve at least provided some reasons to think that moral objectivism is a rationally respectable position and that moral non-naturalism is not the wishful thinking of soft-headed philosophers.
Lewis Vaughn is a writer specializing in philosophy, ethics, critical thinking, and religion. He is the former executive editor of Free Inquiry magazine. His memoir Star Map: A Journey of Faith Doubt and Meaning was published by Freethought House in May 2017.