Moral nihilism

J. L. Mackie argues that moral assertions are only true if there are moral properties, but because there are none, all such claims are false.[5] Under such a view moral propositions which express beliefs are then systematically in error. For under Mackie's view, if there are to be moral properties, they must be objective and therefore not amenable to differences in subjective desires and preferences. Moreover any claims that these moral properties, if they did exist would need to be intrinsically motivating by being in some primitive relation to our consciousness. They must be able of guiding us morally just by the fact of being in some clear awareness of their truth. But this is not the case, and such ideas in his views are plainly queer.

Other versions of the theory claim that moral assertions are not true because they are neither true nor false. This form of moral nihilism claims that moral beliefs and assertions presuppose the existence of moral facts that do not exist. Consider, for example, the claim that the present king of France is bald. Some argue that this claim is neither true nor false because it presupposes that there is currently a king of France, but there is not. The claim suffers from "presupposition failure". Richard Joyce[6] argues for this form of moral nihilism under the name "fictionalism".

Error theory is built on three principles:

1. There are no moral features in this world; nothing is right or wrong.
2. Therefore, no moral judgments are true; however,
3. Our sincere moral judgments try, but always fail, to describe the moral features of things.

Thus, we always lapse into error when thinking in moral terms. We are trying to state the truth when we make moral judgments. But since there is no moral truth, all of our moral claims are mistaken. Hence the error. These three principles lead to the conclusion that there is no moral knowledge. Knowledge requires truth. If there is no moral truth, there can be no moral knowledge. Thus moral values are purely chimerical.[3][7]

The most prominent argument for nihilism is the argument from queerness.

J. L. Mackie argues that there are no objective ethical values, by arguing that they would be queer (strange):

If there were objective values, then they would be entities or qualities or relations of a very strange sort, utterly different from anything else in the universe.[8]

For all those who also find such entities queer (prima facie implausible), there is reason to doubt the existence of objective values.

In his book Morality without Foundations: A Defense of Ethical Contextualism (1999), Mark Timmons provides a reconstruction of Mackie's views in the form of the two related arguments. These are based on the rejection of properties, facts, and relationships that do not fit within the worldview of philosophical naturalism, the idea "that everything—including any particular events, facts, properties, and so on—is part of the natural physical world that science investigates" (1999, p. 12). Timmons adds, "The undeniable attraction of this outlook in contemporary philosophy no doubt stems from the rise of modern science and the belief that science is our best avenue for discovering the nature of reality".[9]

There are several ways in which moral properties are supposedly queer:

• our ordinary moral discourse purports to refer to intrinsically prescriptive properties and facts "that would somehow motivate us or provide us with reasons for action independent of our desires and aversions"—but such properties and facts do not comport with philosophical naturalism.[10]
• given that objective moral properties supposedly supervene upon natural properties (such as biological or psychological properties), the relation between the moral properties and the natural properties is metaphysically mysterious and does not comport with philosophical naturalism.[11]
• a moral realist who countenances the existence of metaphysically queer properties, facts, and relations must also posit some special faculty by which we have knowledge of them.[11]

Christine Korsgaard responds to Mackie by saying:

Of course there are entities that meet these criteria. It's true that they are queer sorts of entities and that knowing them isn't like anything else. But that doesn't mean that they don't exist.... For it is the most familiar fact of human life that the world contains entities that can tell us what to do and make us do it. They are people, and the other animals.[12]

Other criticisms of the argument include noting that for the very fact that such entities would have to be something fundamentally different from what we normally experience—and therefore assumably outside our sphere of experience—we cannot prima facie have reason to either doubt or affirm their existence; therefore, if one had independent grounds for supposing such things to exist (such as, for instance, a reductio ad absurdum of the contrary) then the argument from queerness cannot give one any particular reason to think otherwise. An argument along these lines has been provided by e.g. Akeel Bilgrami.[13]

Gilbert Harman argued that we do not need to posit the existence of objective values in order to explain our 'moral observations'.[14]