Moral Error Theory

Author: Ian Tully
Category: Ethics
Word Count: 1000

Though we often disagree about which actions are morally wrong, most of us would agree that at least some actions are actually wrong. An obvious example is abusing children for fun.

Yet according to the meta-ethical theory known as error theory, it is false that abusing children for fun is wrong (and false that abusing children for fun is right, too!). This is because, according to error theory, all moral statements are false (or neither true nor false).1

This essay will explain this highly counterintuitive view.

John Mackie's (1977) "Ethics: Inventing Right and Wrong"
John Mackie’s (1977) “Ethics: Inventing Right and Wrong”

I. Understanding the Error Theory

The moral error theory originates with J.L. Mackie (1977) and has attracted a number of modern defenders.2

According to one contemporary proponent (Joyce 2001), the view is committed to two theses, the Conceptual Thesis and the Substantive Thesis.

The Conceptual Thesis states that moral statements attempt to make reference to the existence of certain kinds of properties or facts in the world.3 When we use moral language, we are not merely expressing our attitude towards certain things; we are attempting to describe facts about reality.

The Substantive Thesis states that there are no such properties or facts. Therefore, all moral statements are false, attempting to predicate properties or describe facts that do not exist.

Compare moral language with ‘witch’ language. When we make statements about witches, our statements are clearly descriptive. When the people of Salem, MA named certain individuals as witches, they were attributing to them certain features – magical powers, say – constitutive of witchhood. Yet there are no individuals with such powers. So all witch-talk fails to refer; anytime someone names someone else a witch, what that person says is false, in error.

Moral Error Theorist hold that moral language is similarly in error.

2. The Argument from Queerness

Why think moral language is like witch language?

Mackie provides two arguments, which he calls ‘The Argument from Disagreement’ and ‘The Argument from Queerness’. Though both arguments are interesting and powerful, it is the latter argument that will be the focus of this essay.

Mackie sums up the argument as follows: “If there were objective values, then they would be entities…of a very strange sort, utterly different from anything else in the universe. (Mackie 77 – my emphasis). What makes moral properties or “objective values” so utterly strange? The problem is their intrinsic normative authority:

[S]omething’s being good both tells the person who knows this to pursue it and makes him pursue it. An objective good would be sought by anyone who was acquainted with it, not because of any contingent fact that this person, or every person, is so constituted   that he desires this end, but just because the end has to-be-pursuedness somehow built into it (Mackie 78—my emphasis).

Now, the way Mackie spells out the worry has raised concerns that he is attacking a strawman.4

However, there is a more plausible reading of the argument from queerness which claims that what is so mysterious about moral properties is their intrinsic reason-giving force, or what Richard Garner calls their “intrinsic imperativeness” (Garner 2006: 96). According to error theorists, “obligations exist, but they are hypothetical and institutional” (Garner 98). For instance, if I have a desire, say, to see the latest superhero movie, then I have a reason to go to the movies. Such a reason (or obligation) is hypothetical: it holds only if I have the right kind of psychological state – say, a desire. For anyone lacking that state, the reason does not hold.

But the moral realist (according to the error theorist) needs more than this. For genuine moral reasons hold regardless of one’s desires or interests. If someone is drowning in a shallow pond and I can easily save her, then I have a reason – a moral reason – to save her regardless of whether I want to, or whether doing so will further some interest of mine. Moral reasons, then, are said to be categorical.5

But how could there be reasons for action that are utterly independent of our desires, interests, or other psychological attitudes? As Garner puts it: “It is hard to believe in objective prescriptivity because it is hard to make sense of a demand without a demander, and hard to find a place for demands or demanders apart from human interests and conventions” (Garner 102).

In short, the argument for error theory is very simple. When we use moral language, we are attempting to describe or refer to certain properties in the world, properties that provide reasons for action to all rational agents regardless of their interests or attitudes. Yet we can make no sense of what these properties are like. Such language is, arguably, merely a holdover from a theistic worldview, an attempt to have laws without the lawgiver, laws or commands that are somehow built right into the fabric of the world. So, we should reject the existence of moral facts or properties, just as we’ve rejected the existence of witches.

3. Responses

Moral error theory is a radically counterintuitive view. Not surprisingly, then, it has attracted a number of criticisms.

One line of response attacks the conceptual thesis discussed above. Recall that error theorists argue that genuine moral reasons must be categorical. Such a claim is exactly like saying that genuine bachelors must be unmarried: a person simply couldn’t be a bachelor if he were married.

Likewise, say error theorists, a reason simply couldn’t be a moral reason if were not categorical. However, many philosophers have disputed this.6 Perhaps moral reasons are, like all reasons, (merely) hypothetical. But if the error theorist’s conceptual claim is false, then error theory can’t get off the ground.

However, such a reply seems to concede quite a lot to error theorists. Thus, some philosophers (Cuneo 2007; Rowlands 2013) choose instead to attack the substantive thesis, arguing that categorical reasons are not problematic after all. A favorite strategy here is to argue that other sorts of reasons are also categorical, namely, epistemic reasons.

So, for instance, they argue that the fact that the Earth orbits the Sun is a reason for anyone, regardless of her desires, interests, or inclinations, to believe in the heliocentric theory of the solar system.

But if there can be categorical epistemic reasons, why can’t there be categorical moral reasons?


You may be wondering how error theorists can claim that all moral statements are false. After all, by the law of excluded middle, a statement and its negation can’t both be false. There are a number of ways around this worry: see Sinnott-Armstrong (2006) and Olson (2010) for details.

Joyce 2001; Olson 2010; Garner 2012.

In philosophical jargon, the claim is that moral statements are “cognitive” or “truth apt.”

The way Mackie describes the worry makes it sound as though recognition of the fact that x is good would not only provide reason for any agent to pursue x, but would make anyone pursue x. This commits the moral realist to a very strong version of motivational internalism, the thesis that moral facts are intrinsically motivating. But motivational internalism in any form is highly controversial, for it has seemed coherent to many philosophers that a person might sincerely judge that it is right to φ, and yet feel no motivation whatsoever to φ (Brink 1986). At any rate, few, if any, moral realists would subscribe to Mackie’s very strong version of the view.

Some error theorists think this line of reasoning doesn’t go far enough. They contend that all reasons, oughts, or other normative (as opposed to descriptive) phenomena are mysterious or ‘queer’. So there aren’t any moral reasons, because there aren’t any reasons at all!

See, e.g., Shafer-Landau (2005: 111); Kelly et al (2007); Cuneo (2012).


Brink, David. (1986) “Externalist Moral Realism.” Southern Journal of Philosophy Supplement: 23-42.

Cuneo, Terence. (2012) “Moral Naturalism and Categorical Reasons.” In Susana Nuccetelli and Gary Seay, eds. Ethical Naturalism: Current Debates. New York: Cambridge University Press.

———. (2007) The Normative Web. New York: Oxford University Press.

Garner, Richard. (2006) “On The Genuine Queerness of Moral Properties and Facts.” In Arguing About Metaethics, Andrew Fischer and Simon Kirchin, eds. New York: Routledge. Pgs. 96-107.

Joyce, Richard. (2001) The Myth of Morality. New York: Cambridge University Press. Kelly, D., Stich, S.,

Haley, K., Eng, S., and Fessler, D. (2007) “Harm, Affect, and the Moral/Conventional Distinction.” Mind & Language, Vol. 22 No. 2. Pgs. 117–131.

Mackie, John L. (1977) Ethics: Inventing Right and Wrong. New York: Penguin Books.

Olson, Jonas. (2010) “In Defense of Moral Error Theory,” in Michael Brady, ed., New Waves in Metaethics, Basingstoke: Palgrave Macmillan, 62-84.

Rowland, Richard. (2013) “Moral Error Theory and The Argument From Epistemic Reasons.” Journal of Ethics and Social Philosophy Vol 7 No 1.

Shafer-Landau, Russ. (2005) “Error Theory and the Possibility of Normative Theory.” Philosophical Issues (Normativity) [15] Pgs. 107-120.

Sinnott-Armstrong, Walter. (2006) Moral Skepticisms. Oxford: Oxford University Press.

Related Essays

Ethical Realism by Thomas Metcalf

Because God Says So: On Divine Command Theory by Spencer Case

Cultural Relativism: Do Cultural Norms Make Actions Right and Wrong? by Nathan Nobis

Evolution and Ethics by Michael Klenk

Reason is the Slave to the Passions: Hume on Reason vs. Desire by Daniel Weltman

About the Author

Ian Tully is a Postdoctoral Fellow in Philosophy and Mental Disorder at Johns Hopkins University’s Berman Institute of Bioethics. He completed his PhD in philosophy at Washington University in St. Louis. He also holds an M.A. in philosophy from the University of Colorado at Boulder and a B.A. in philosophy from George Washington University. He is interested in ethics, metaethics, moral psychology, and the philosophy of mind.

Follow 1000-Word Philosophy on Facebook, Twitter and subscribe to receive email notice of new essays at the bottom of