Moral Skepticism

Positions denying that we have moral knowledge or that any moral beliefs are justified.

Definition

Moral scepticism, in its epistemological form, is the view that no one has moral knowledge, or more weakly that no moral belief is epistemically justified; it is distinguished from the metaphysical scepticism of the error theory, which denies that there are moral facts.

Scope

This topic surveys epistemological moral scepticism — the family of views holding that we lack moral knowledge or justified moral belief — and distinguishes it from metaphysical scepticism (error theory) and Pyrrhonian variants. It examines the principal sceptical arguments from disagreement, regress, and evolutionary debunking, and the strategies used to resist them, including reliabilist and modest-foundationalist replies.

Core questions

• Is moral scepticism a claim about knowledge, about justification, or about moral facts?
• Do regress and disagreement arguments establish that moral beliefs are unjustified?
• Do evolutionary debunking arguments undermine the reliability of moral belief?
• Can moderate foundationalism or reliabilism answer the sceptic?

Key concepts

• epistemological vs. metaphysical skepticism
• regress problem
• Pyrrhonism
• debunking arguments
• contrastivism

Key theories

Pyrrhonian and dogmatic moral skepticism

Sinnott-Armstrong distinguishes varieties of moral scepticism and defends a moderate Pyrrhonian scepticism about moral knowledge while allowing some justified moral belief on a contrastivist account.

Evolutionary debunking

If our moral beliefs are products of evolutionary pressures unconnected to moral truth, their reliability is undercut, supporting scepticism about moral knowledge.

History

Moral scepticism has ancient roots in Pyrrhonism and the relativizing reports of the sophists. In modern metaethics it is sharpened by Mackie's queerness and relativity arguments, by Sinnott-Armstrong's systematic taxonomy of moral scepticisms (2006), and by the evolutionary debunking arguments developed by Joyce and Street.

Debates

The reach of debunking arguments

Debunkers argue evolutionary origins undermine the justification of moral belief; critics reply that genealogical claims do not by themselves show beliefs false or unjustified, and that some moral beliefs may track truth.

Justification without certainty

Anti-sceptics argue that moral beliefs can be justified even if not indubitable, using modest foundationalism or reliabilism; Sinnott-Armstrong's contrastivism reframes when scepticism does and does not bite.

Key figures

• Walter Sinnott-Armstrong
• J. L. Mackie
• Richard Joyce

Seminal works

• mackie1977
• sinnottarmstrong2006
• joyce2006

Frequently asked questions

Is the moral sceptic saying nothing is really right or wrong?

Not necessarily. Epistemological moral scepticism is about whether we can know or justifiably believe moral claims; it leaves open whether there are moral facts. The view that there are no moral facts is the separate metaphysical thesis of the error theory.