The argument from queerness is J.L. Mackie’s challenge to moral realism: if objective moral values existed, they would be bizarre, unlike anything else in the world. In Ethics, it is a reason to doubt mind-independent moral facts.
The argument from queerness is an anti-realist argument in Ethics that says objective moral properties would be so unlike ordinary facts that their existence looks implausible. J.L. Mackie is the philosopher most closely linked to it. His basic point is that if there were moral facts that existed independently of human minds, they would have to be a very strange kind of thing, not like physical objects, not like emotions, and not like social conventions.
That strangeness matters because moral realism claims that statements such as “lying is wrong” can be true whether or not anyone agrees. Mackie thinks that if this were true, we would need a special kind of moral property built into reality itself. But moral properties do not seem to show up in the world the way trees, atoms, or laws of motion do. You can measure a temperature, but you cannot point to “wrongness” with a microscope.
The argument has two sides. First is the metaphysical side, which says objective moral values would be ontologically odd. Second is the epistemic side, which asks how we could know about such values if they are not observable and do not interact with the physical world in any clear way. If moral truths are real but totally unlike everything else we know, then our usual methods of knowing start to look weak.
That does not mean the argument proves moral realism false. It is a challenge, not a final verdict. Realists can reply that moral facts do not need to be physical to be real, or that lots of important things are not directly observable but are still reasonable to believe in. Critics also argue that Mackie treats morality as if it had to be a weird object, when moral realism might instead describe patterns of reasons, obligations, or truths that are not material but still legitimate.
In Ethics class, this term usually comes up when you compare moral realism to moral anti-realism. It also fits into debates about moral discourse, because the way we talk about right and wrong may sound objective even if the facts behind that talk are not.
This argument matters because it gives you a clear reason why some philosophers reject moral realism instead of just saying, “I don’t like it.” Mackie gives anti-realism a specific criticism: objective morality would require a weird kind of reality that seems out of step with everything else we know about the world.
That makes the term useful in meta-ethics, where the question is not “What is the right action?” but “What makes moral claims true or false at all?” If you are reading an ethics passage that argues morality is human-made, socially constructed, or tied to attitudes rather than facts, the argument from queerness is often part of the logic behind it.
It also helps you spot the difference between moral disagreement and moral skepticism. People disagree about whether stealing is wrong, but the argument from queerness asks a deeper question: even if people disagree, are there objective moral facts there in the first place? That is a different issue from whether we can settle the disagreement nicely.
You will also see this term when a prompt asks you to compare moral realism with subjectivist or skeptical views. The argument gives a strong way to explain why someone might think morality is real only as a human practice, not as an independent feature of the universe.
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Visual cheatsheet
view galleryMoral Realism
Moral realism is the view that moral facts exist independently of what anyone believes. The argument from queerness is aimed at this view because it says those facts would be so strange that we have reason to doubt they exist. If a prompt asks why realism is controversial, this argument gives you one of the classic objections.
Moral Anti-Realism
Moral anti-realism includes views that deny objective moral facts or explain morality in mind-dependent terms. Mackie’s argument pushes you toward anti-realism by making objective morality look ontologically costly. In an essay, you can use it to explain why someone might treat moral claims as human practices rather than facts built into reality.
J.L. Mackie
J.L. Mackie is the philosopher most associated with the argument from queerness. When his name appears, the point is usually that he challenged objective morality by calling it oddly “queer” in both its existence and how we would know it. He is the main source for this anti-realist line of thought.
Moral Discourse
Moral discourse is the way people talk and reason about right and wrong. The argument from queerness pressures this language by asking whether our moral talk really tracks objective facts or just expresses attitudes, norms, or social expectations. That makes it useful when analyzing whether moral language sounds factual even if it may not be.
A short-answer question might give you a passage from Mackie and ask what he is arguing against. Your move is to say that the argument from queerness challenges moral realism by claiming objective moral properties would be bizarre and hard to explain. If a teacher asks you to compare views, connect it to moral anti-realism or moral skepticism and explain that the issue is not just disagreement, but whether moral facts exist at all.
In an essay, use it as an objection, not as a full theory. You can say, for example, that a realist must answer Mackie by showing why moral facts are not as “queer” as they seem, or why non-physical truths are still plausible. If the class uses cases or discussion prompts, it often appears when you debate whether morality is discovered or constructed.
Moral skepticism questions whether moral knowledge is possible or whether moral claims can be justified. The argument from queerness is narrower: it says objective moral facts themselves seem metaphysically strange. You can be skeptical about knowing moral truths without making Mackie’s stronger claim that such truths are unlikely to exist at all.
The argument from queerness says objective moral facts would be strangely unlike ordinary facts, so moral realism looks doubtful.
J.L. Mackie is the philosopher most closely tied to this argument, and his work is a major source for moral anti-realism in Ethics.
The argument has two parts: moral values seem metaphysically weird, and they would also be hard to know about if they existed.
It does not prove that morality is fake, but it gives a serious objection that realists have to answer.
If you see this term in class, connect it to the larger debate over whether moral claims describe objective truths or human-made practices.
It is the claim that if objective moral properties existed, they would be very strange, unlike anything else in the natural world. Because of that, J.L. Mackie argues we should doubt moral realism. In Ethics, it is a classic anti-realist objection to mind-independent morality.
The argument is most closely associated with J.L. Mackie. He used it as part of his case against objective moral values. When you see his name in a meta-ethics unit, the queerness argument is usually one of the main ideas being discussed.
Not exactly. Moral skepticism questions whether we can know moral truths or justify moral beliefs. The argument from queerness goes further by saying objective moral facts themselves would be ontologically odd, so their existence is doubtful. It is one way to support anti-realism.
Use it as an objection to moral realism. You can explain that Mackie thinks objective moral values would need a strange, non-physical kind of existence, and that we have no good reason to accept that. Then you can contrast it with a realist reply, such as the claim that moral truths do not need to be physical to be real.