Card 1.3.1 · Root I — Metaphysics
The Mind–Body Problem
How can a thought move an arm?
This node asks how mental states relate to physical states — whether thought is something the brain does, something the brain has, or something else entirely.
Where it sits
Under 1.3 Philosophy of mind. Depends on 1.4.2 Causation. Feeds 1.7 Free will.
The rival answers
| Position | Mental states are | Problem it faces |
|---|---|---|
| Substance dualism | A distinct non-physical substance | How two substances interact at all |
| Property dualism | Non-physical properties of physical things | Whether such properties do any causal work |
| Identity theory | Identical to brain states | The same mental-state type may be realised by different physical kinds, across species or systems |
| Functionalism | Defined by their causal roles, not by what realises them | Critics object that it leaves out what experience is like |
| Eliminative materialism | Some or all, as common sense describes them, do not exist | Critics object that it discards the very data a theory of mind must explain |
| Epiphenomenalism | Real but causally inert by-products | Critics object that it cannot vindicate our sense of agency or our knowledge of our own experiences |
| Panpsychism | Grounded in, or continuous with, mentality that is fundamental and widespread in nature | For constitutive forms, how many small subjects make one subject; non-constitutive forms face other combination worries |
Key figures
| Figure | Dates | Tradition | Contribution |
|---|---|---|---|
| René Descartes | 1596–1650 | European modern | Stated the problem in its modern form |
| Elisabeth of Bohemia | 1618–1680 | European modern | Pressed Descartes on how an unextended mind could move the body — an objection his replies did not resolve for many later readers |
| Nicolas Malebranche | 1638–1715 | European modern | Occasionalism: God is the only real cause; created events are occasions for God’s action |
| Baruch Spinoza | 1632–1677 | European modern | One substance with infinitely many attributes, of which thought and extension are the two known to us |
| U. T. Place | 1924–2000 | Analytic | Proposed that consciousness is a brain process (1956) |
| J. J. C. Smart | 1920–2012 | Analytic | Developed and defended mind–brain identity theory (1959) |
| Hilary Putnam | 1926–2016 | Analytic | Multiple realisability; the case for functionalism |
| Anton Wilhelm Amo | c. 1703–after 1752 | African | The mind is impassive: it cannot be acted on, so sensation belongs to the body; yet the mind can use the body as an instrument and effect things through it by intentions |
| Anne Conway | 1631–1679 | European modern | Within created nature, spirit and body differ in degree within one living created substance; Conway’s wider ontology distinguishes God, Christ or “Middle Nature,” and creatures |
Connections
→ 1.3, 1.4.2 · ↔ 1.7, 6.14, 6.17, 1.3.4 · ◇ substance dualism, property dualism, identity theory, functionalism, eliminative materialism, epiphenomenalism, panpsychism · ○ Early modern; Modern; Table 2
→ narrower questions · ↔ questions it borders · ◇ the positions, mapped in Part III of the book · ○ the eras and comparison tables (Parts IV and V)
The full card is in the book
In The Coordinates of Thought this card goes on to a worked example that sets the answers against one case, and to where the question touches daily life — page 45.
On Coordinates of Thought
Conversations about this question in Consciousness:
- Consciousness is fundamental, not produced by the brain 9 replies
- We will never have a test for machine consciousness, and we should say so plainly 6 replies
- Functionalism is officially neutral, but in practice it is materialism with better manners 6 replies
- Nishida’s pure experience dissolves the hard problem rather than solving it 6 replies
- Reading group: the Elisabeth–Descartes letters of 1643, slowly 6 replies