Evolutionary Debunking Arguments

Arguments that the evolutionary origins of our moral beliefs undermine their justification or the case for moral realism.

Definition

An evolutionary debunking argument contends that because our moral beliefs or evaluative attitudes are the product of evolutionary forces that selected for reproductive fitness rather than moral truth, those beliefs are unjustified, or moral realism is untenable, since realists cannot explain how the beliefs could track mind-independent moral facts.

Scope

This topic covers evolutionary debunking arguments in metaethics: attempts to use the natural history of our moral capacities to cast epistemic doubt on moral beliefs or to pressure moral realism. It centers on Street's Darwinian dilemma against realist theories of value and Joyce's genealogical debunking, and surveys realist replies including third-factor accounts and the charge that such arguments overgeneralize to all belief.

Core questions

• Does the evolutionary origin of moral belief give us reason to doubt its reliability?
• Can the realist explain a correlation between our evaluative attitudes and the moral truth?
• Do debunking arguments overgeneralize to perceptual and mathematical belief?
• Is constructivism or antirealism better placed to absorb the evolutionary genealogy?

Key concepts

• Darwinian dilemma
• tracking account
• adaptive-link account
• third-factor reply
• overgeneralization objection

Key theories

The Darwinian dilemma

Street argues the realist must either deny that selection influenced our evaluative attitudes (implausible) or affirm it and then fail to explain how those attitudes track independent moral facts, so realism faces a dilemma that antirealist constructivism avoids.

Genealogical debunking

Joyce argues that an evolutionary explanation of why we hold moral beliefs is available without supposing those beliefs are true, which removes our justification for them and supports a sceptical or fictionalist stance.

History

Building on earlier suggestions by Ruse and on Mackie, Street's 2006 Darwinian dilemma and Joyce's The Evolution of Morality (2006) made evolutionary debunking a central topic. Kahane (2011) clarified the general structure of debunking arguments, and a large literature of realist replies followed.

Debates

The overgeneralization worry

Critics argue that if evolutionary origins debunk moral belief, they equally debunk perceptual and mathematical belief, which is unacceptable; debunkers reply that the moral case is relevantly different because there is no truth-tracking explanation available.

Third-factor replies

Realists posit a third factor that explains both the evolutionary advantage and the truth of certain moral beliefs (e.g. that survival is good), so selection indirectly correlated belief with truth; debunkers charge this begs the question.

Key figures

• Sharon Street
• Richard Joyce
• Guy Kahane

Seminal works

• street2006
• joyce2006
• kahanesigrun2011

Frequently asked questions

Does evolutionary debunking prove there are no moral facts?

No. At most it aims to show our moral beliefs are unjustified or that realism cannot explain their reliability. It is an epistemic challenge; whether it also supports a metaphysical conclusion like antirealism is contested.