Supervenience and the Explanatory Gap

Supervenience captures the idea that the mental depends on the physical without being reducible to it, while the explanatory gap names our inability to explain why physical processes give rise to experience.

Definition

Supervenience is a relation of covariation and dependence on which there can be no mental difference without a physical difference; the explanatory gap is the apparent absence of any explanation of why a given physical state should be accompanied by a particular conscious experience.

Scope

This topic covers supervenience as a dependence relation used to articulate non-reductive physicalism, its weak, strong, and global varieties, and the explanatory gap between physical and phenomenal descriptions. It connects these notions to debates over whether dependence without reduction is intelligible.

Core questions

• Can the mental depend on the physical without being reducible to it?
• Which form of supervenience best captures psychophysical dependence?
• Why does no physical explanation seem to close the gap to conscious experience?
• Is the explanatory gap merely epistemic, or does it signal a metaphysical divide?

Key concepts

• weak supervenience
• strong supervenience
• global supervenience
• anomalous monism
• explanatory gap
• conceivability

Key theories

Non-reductive physicalism via supervenience

Mental properties supervene on physical properties, securing the dependence of the mental on the physical while denying type identity or reduction.

The explanatory gap

Even granting that the physical determines the phenomenal, physical accounts leave unexplained why a given physical state should feel the way it does.

History

Davidson's anomalous monism (1970) introduced supervenience into philosophy of mind as a way to combine token physicalism with the irreducibility of the mental. Kim systematized the formal varieties of supervenience and pressed their limits, while Levine (1983) named the explanatory gap, which Chalmers (1996) later mobilized in his case against reductive physicalism.

Debates

Epistemic versus ontological gap

Whether the explanatory gap reflects only a limit on human explanation or instead reveals a genuine ontological distinctness of the phenomenal.

Adequacy of supervenience

Whether mere supervenience is enough to count as physicalism, or whether it leaves the dependence relation unexplained.

Key figures

• Joseph Levine
• Jaegwon Kim
• Donald Davidson
• David Chalmers

Seminal works

• davidson1970
• levine1983
• kim1993

Frequently asked questions

Does supervenience mean the mental is reducible to the physical?

Not necessarily. Supervenience asserts dependence and covariation, but non-reductive physicalists hold that the mental can supervene on the physical without being reducible to it.