Descartes Legacy Slides
Philosophy of Mind • Chapter 3 John Heil
Cartesian Dualism & Its Aftermath
Descartes’s Legacy
How the failure of mind–body interaction gave birth to parallelism, occasionalism, idealism, epiphenomenalism, and non-Cartesian dualism.
Lecture & Seminar Presentation 12 Slides
The Starting Predicament
The Crisis of Interaction
The Cartesian Chasm
Descartes defined matter as extended and unthinking, and mind as thinking and unextended.
Sharing zero essential properties, how can an unextended soul push, pull, or receive motion from physical bodies?
Princess Elizabeth’s Challenge
“It would be easier for me to attribute matter and extension to the soul than to attribute capacity to move a body to an immaterial entity.”
Causation assumed transference & contact; Descartes could offer only the pineal gland.
The Dilemma: Either explain how two radically disjoint substances interact, or reconstruct dualism without interaction.
Alternative 1 • Leibniz
Psycho-Physical Parallelism
Covariation Without Causation
Mental sequences and physical sequences run side-by-side like synchronized tracks. They correspond perfectly, but neither causes the other.
The Two Clocks Analogy
Two identical chronometers keep exact time together not because they communicate, but because a supreme clockmaker tuned both beforehand.
Heil’s Diagnostic Critique
The “Brute Fact” Problem
Treating lifelong mental-physical synchrony as an inexplicable brute coincidence is ad hoc.
The Deus Ex Machina
Appealing to God to coordinate two parallel tracks merely invents a contrived fix to rescue dualism.
Sitting on a tack does not cause pain; the physical tack-event merely coincides with the mental pain-event.
Alternative 2 • Malebranche
Occasionalism: The Active Deity
1
Occasional Causes
Creatures have no genuine causal efficacy. When your foot steps on a tack, this is merely an “occasion” for God to act.
Neither mind nor body possesses true power.
2
Divine Alignment
God wills both your bodily leap and your sensation of agony, maintaining an orderly alignment between the mental and material realms.
Ensures reality behaves in an orderly, lawlike way.
3
The Philosophical Hitch
If God is unextended, how does God move physical matter? All Cartesian interaction worries reappear at the divine level!
Moves the mystery from humans to the Creator.
Occasionalism is not just a bizarre religious tangent—it was driven by a radical and rigorous theory of causation.
Metaphysical Foundations
Causation & The Universe in Stages
No Horizontal Causal Nexus
Events are discrete, momentary slices. Striking a billiard ball at time t₁ has no inherent metaphysical power to generate rolling at t₂.
Vertical “Film Strip” Creation
Like frames on a movie reel, frame 1 does not cause frame 2. The projector lamp (God) recreates each momentary universe ex nihilo in continuous succession.
Anticipating David Hume
- Malebranche formulated Hume’s famous critique decades before Hume: we observe sequence, never the necessary connection.
- If there is no physical mechanism linking billiard balls either, mental-physical interaction is no worse off than physics!
- Order must come from outside the sequence: a benevolent God sustaining natural laws.
Figure 3.3 & 3.4 in Heil Continuous Creation: Universe at t₁ → t₂ → t₃ → t₄
Alternative 3 • Berkeley
Idealism: Eliminating Matter
The Radically Simple Move
If material-mental interaction is baffling, why assume a material world exists at all?
Idealism: The world consists exclusively of minds and their ideas. Material substance is an unmotivated, superfluous hypothesis.
Saving Appearances: Idealism does not make tables ghostly; your experiences remain just as solid, vivid, and predictable.
The Experimental Refutation Fails
Dr. Johnson kicked a stone and shouted, “I refute Berkeley thus!”
Berkeley replies: kicking a stone yields a vivid sensory experience (tactile feel, visual motion, thud sound). Observations are experiences; they never take you outside the mind!
Even particle detectors and cloud chambers in physics are, for the observer, conscious sensory inputs.
Heil: “Unable to reconcile minds and the material universe, the idealist gives up the game and stuffs the universe inside the mind.”
Berkeley's Semantic Masterstroke
Mind & Meaning: The Unthinkable Object
The Ripe Tomato Analysis
Think of a ripe tomato in sunlight. What makes up your concept?
- Visual redness and spherical shape
- Smooth texture, firm skin feel
- Distinctive acidic taste and aroma
All of these are conscious sensory qualities. Your thoughts about the tomato are exhausted by them.
“Experiences Can Only Resemble Experiences”
To imagine a “mind-independent tomato,” you summon sensory qualities, then subtract the fact that they are experiences!
Like a Three-Sided Triangle
It is like imagining a triangle and subtracting that it has three sides. The words remain, but they are devoid of significance.
For Berkeley, philosophical talk of mind-independent matter is unintelligible nonsense.
Alternative 4 • Huxley & Jackson
Epiphenomenalism: The One-Way Street
Causal Closure Preserved
Every physical event has an exclusively physical cause. The material universe is closed, self-contained, and obeys conservation laws.
Mental States as Inert Byproducts
Physical brain processes generate conscious experiences (qualia), but these mental states have zero physical or mental effects.
Classic Mechanical Analogies
Heat from a Computer
Produced by processing, but does not drive computations.
The Locomotive Whistle
Accompanies the engine’s movement, but does not power the train.
The Ball’s Shadow
Follows the billiard ball across the green felt, but displaces nothing.
You pull into Burger King because a brain state caused both your decision and your driving—not because the conscious thought moved you.
Evaluating Epiphenomenalism
Dangling Causes & Explanatory Costs
“Dangling” Relations
Everywhere in physics, events are both effects and causes. Epiphenomenalism introduces bizarre dead-end causes that produce no subsequent events.
Term coined by Feigl and Smart.
Ockham’s Razor
The Principle of Parsimony bids us not to multiply entities without necessity. Why posit causally inert mental ghosts if physics does all the work?
Simpler theories win by default.
Conservation Laws
Does a material event generating a mental quale require energy to exit the physical universe? If so, conservation of mass-energy is broken.
Threatens physics or requires free energy.
Why Scientists Love It: Neuroscientists can investigate brain mechanics exclusively, treating conscious qualia as ignorable epiphenomena.
Contemporary Frontier • Section 3.7
Non-Cartesian Dualism: E. J. Lowe
Substance Dualism Without Immateriality
Lowe argues that the self and the body are two distinct individual substances, yet the self is not an immaterial Cartesian ghost.
The Statue & The Lump of Bronze
A bronze statue of Athena coincides with a lump of bronze, but they are not identical. The lump survives being melted; the statue survives replacing an arm. Different persistence conditions = distinct substances!
The Architecture of the Self
The Self is a Simple Substance
Lacks substantial parts. Your brain is a part of your body, but not a part of you.
Derivative vs. Non-Derivative Properties
You have two arms derivatively (via your body). But you have mass, height, thoughts, and feelings non-derivatively.
Lowe breaks Descartes’s dogma: a single substance (the self) can possess both mental and physical properties.
A New Model of Agency
The Self as Shaper of Causal Patterns
The Flaw in the Linear Chain
Cartesians picture a linear chain: M₁ → E₁ → E₂ → B₁. But backwards tracing from leg muscles reveals a vast, tangled web extending into events before your birth!
Shaping vs. Initiating
Nothing in physics “initiates” a closed causal chain. Lowe (echoing Kant) proposes: the self affects nature by bringing it about that causal sequences take on a particular overall shape.
The Spider on the Web Analogy
A spider scuttles across its web. The web is causally dependent on the spider, but it is an independent substance.
The web does not initiate the spider’s leg motions; rather, it enables, facilitates, and constrains them, determining which causal patterns exist in the world.
The self shapes bodily neural traffic without violating physical conservation laws.
Figure 3.8 vs. 3.9 in Heil Non-Cartesian Dualism respects physical causal closure.
Chapter 3 Synthesis
The Landscape of Descartes’s Legacy
| Position | Substance Ontology | Causal Mechanics | Core Vulnerability |
|---|
| Parallelism | Minds & Matter (Dualism) | Zero interaction; pre-set harmony | Ad hoc brute correlation / God |
| Occasionalism | Minds & Matter (Dualism) | Continual divine recreation | Divine interaction puzzle remains |
| Idealism | Minds & Ideas only (Monism) | Minds or God order experiences | Stuffs physical universe into mind |
| Epiphenomenalism | Material substances (+ Qualia) | One-way: Body → Mind only | Dangling causes; mental impotence |
| Non-Cartesian Dualism | Two substances (Self & Body) | Self shapes causal patterns | Metaphysics of “pattern shaping” |
Next Step: Chapter 4 • Mind and Behavior (The Materialist Shift) Philosophy of Mind • Heil 4th Ed.
