Ethical Naturalism

The view that moral properties are natural properties, accessible in principle to empirical inquiry.

Definition

Ethical naturalism is the metaethical view that moral properties exist and are identical with, or constituted by, natural properties — features of the sort investigated by the natural and social sciences — so that moral facts are a species of natural fact.

Scope

This topic covers ethical naturalism in its main forms: reductive naturalism, which identifies moral properties with specific natural properties, and non-reductive or synthetic (Cornell) naturalism, which treats moral properties as natural kinds picked out a posteriori. It examines analytic versus synthetic versions, the role of reference and natural-kind semantics, and how naturalism positions itself against both non-naturalism and antirealism.

Core questions

• Are moral properties identical to, reducible to, or merely constituted by natural properties?
• Is the identity analytic (knowable by meaning) or synthetic (knowable a posteriori)?
• How do moral terms come to refer to natural properties?
• Can naturalism preserve the normativity and authority of morality?

Key concepts

• natural property
• synthetic vs. analytic naturalism
• causal theory of reference
• reduction
• homeostatic property cluster

Key theories

Synthetic (Cornell) naturalism

Moral properties are natural properties identified a posteriori via causal-regulation theories of reference, analogous to the identification of water with H2O, so moral terms refer to natural kinds without synonymy.

Reductive naturalism

Railton identifies a person's non-moral good with what they would want themselves to want under full information, and moral rightness with what is instrumentally rational from a social point of view, giving moral facts a naturalistic reduction.

Analytic descriptivism

Jackson argues mature folk morality fixes the reference of moral terms to whatever natural properties best play the relevant role, supporting an analytic form of naturalism via conceptual analysis.

History

After decades in which Moore's open-question argument was thought to refute naturalism, the causal theory of reference reopened the door. In the 1980s Boyd and Railton developed Cornell realism, a synthetic naturalism modelled on scientific natural kinds, while Jackson later defended an analytic descriptivist naturalism.

Debates

Analytic versus synthetic naturalism

Analytic naturalists ground moral-natural identities in conceptual analysis, while synthetic naturalists deny synonymy and rely on a posteriori reference; each must answer the open-question and Moral Twin Earth challenges.

Naturalism and normativity

Critics argue that reducing moral facts to natural facts loses morality's distinctive normative authority; naturalists reply that natural facts can themselves be reason-giving.

Key figures

• Richard Boyd
• Peter Railton
• Frank Jackson

Seminal works

• railton1986
• boyd1988
• jacksonfrank1998

Frequently asked questions

Can a naturalist be a moral realist?

Yes. Most ethical naturalists are realists: they hold that there are objective moral facts and that those facts are natural facts. Naturalism is in fact one of the main ways of being a moral realist.