Substance and Property Dualism

Dualism holds that the mental and the physical are fundamentally different in kind, either as distinct substances or as distinct families of properties.

Definition

Dualism is the view that mind and matter are two distinct kinds of thing: substance dualism treats the mind as a non-physical substance, while property dualism treats mental properties as non-physical properties of an otherwise physical substance.

Scope

This topic covers substance dualism, on which the mind is a distinct non-physical substance, and property dualism, on which a single physical substance bears irreducible mental properties. It includes Cartesian dualism, epiphenomenalism, and conceivability and knowledge arguments advanced in support of dualist conclusions.

Core questions

• Is the mind a distinct substance, or only a set of distinct properties of the brain?
• Do conceivability and knowledge arguments establish that consciousness is non-physical?
• If mental properties are non-physical, can they have causal effects?

Key concepts

• res cogitans
• res extensa
• epiphenomenalism
• qualia
• conceivability argument
• knowledge argument

Key theories

Cartesian substance dualism

The mind is an immaterial thinking substance really distinct from the extended, material body, as argued through the conceivability of disembodied existence.

Property dualism

There is one kind of substance, the physical, but it bears irreducible phenomenal properties that do not reduce to physical properties, a view defended via arguments such as the knowledge argument and the conceivability of zombies.

History

Substance dualism received its canonical modern statement in Descartes's Meditations (1641). After mid-twentieth-century physicalism eclipsed it, property dualism revived dualist thinking through Jackson's knowledge argument (1982) and Chalmers's defense of the conceivability of zombies (1996), shifting the debate from substances to irreducible phenomenal properties.

Debates

Causal efficacy of the mental

Whether non-physical minds or properties can cause physical events, with epiphenomenalism conceding that they cannot.

Force of conceivability arguments

Whether the conceivability of disembodiment or of zombies licenses metaphysical conclusions about the non-physicality of mind.

Key figures

• Rene Descartes
• Frank Jackson
• David Chalmers

Seminal works

• descartes1641
• jackson1982
• chalmers1996

Frequently asked questions

What is the difference between substance and property dualism?

Substance dualism posits two kinds of substance, mental and physical, whereas property dualism posits one physical substance with two kinds of property, physical and mental.