Podcast brief
Place and Smart on Mind-Brain Identity Theory
Four hosts work through U.T. Place's and J.J.C. Smart's classic papers defending the identity theory of mind and brain.
A Stoa brief of an episode from The Partially Examined Life
Ep. 401: Mind/Brain Identity Theory (U.T. Place, J.J.C. Smart) (Part Two)
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The brief
This conversation works through two founding papers of mind-brain identity theory, U.T. Place's "Is Consciousness a Brain Process?" and J.J.C. Smart's "Sensations and Brain Processes," asking whether identifying mental states with brain states can survive the objections built against it. The hosts conclude that the strongest moves in both papers are clever but leave real doubts, especially about whether talk of subjective qualities can be translated away without residue.
They start with what justifies an identity claim at all. Place treats identity as stronger than correlation or causation, using lightning and electric charge motion as a model, and the hosts test whether the same logic can stretch to mind and brain. Place's phenomenological fallacy then becomes central: he argues that describing an experience, like a green afterimage, is not describing an inner object on a mental screen but describing the world using language learned for recognizing real things. One host finds exhaustion a sharper test case than pain, since a person can feel exhausted and later discover they were not actually depleted, which exposes a gap between felt state and objective fact.
Smart's paper adds the machinery of strict identity, illustrated by the morning star and evening star, and his responses to objections. The hardest is Max Black's: identifying a sensation with a brain process does not seem to remove the real quality of what the sensation is like, such as a yellow flash. Smart answers with topic-neutral language, describing a sensation as something going on that resembles what happens when a normal observer sees a colored object. Most of the hosts doubt the word "like" can do this work without quietly reintroducing the qualia it was meant to eliminate.
One host reframes the whole dispute as epistemological rather than ontological: the puzzle may be about whether experience can be externally verified, not about what exists. Another resists collapsing the two questions. The episode closes with Smart's inverse zombie case, where he argues that positing immaterial "ghost stuff" is intelligible but less economical than brain stuff, a parsimony argument one host finds persuasive and another finds weak. The group ends skeptical that any of these moves settle the hard problem, and plans to turn next to emergentism.
Strongest arguments
Identity claims require more than correlation or causation
0:52The hosts work through Place's idea that scientific identity statements, like lightning being the motion of electric charges, are stronger than mere correlation or causation. They debate whether a continuum from correlation to causation to identity, including a notion of compositional causality, can justify treating mind-brain identity the same way.
The phenomenological fallacy denies an inner phenomenal screen
8:29Place argues that describing an experience, such as a green afterimage, does not describe a literal green object on an internal cinema screen. Instead, we describe our consciousness by reference to the real physical properties of external objects, using language learned for recognizing the world, not an inner representational medium.
Exhaustion and pain test whether we can misdescribe our own qualia
21:24Mark argues that exhaustion is a clearer test case than pain for Place's view, since someone can feel exhausted and later realize they were not actually depleted, showing a mismatch between momentary feeling and objective state. The hosts use this to probe whether qualia talk is just a confused way of talking about bodily and behavioral conditions.
Seth reframes the problem as epistemological rather than ontological
18:37Seth argues the real question is not whether qualia exist as objects but whether internal subjective experience could ever be externally verified. He suggests that what looks like a metaphysical puzzle about consciousness may really be confusion about observation and verification rather than a fact about what exists.
Smart's strict identity and the morning star analogy
28:55Smart distinguishes strict identity, like a number identical to another description of the same number, from looser cases like an old man being a time-slice of the same four-dimensional object as the boy he once was. Mark uses the morning star and evening star case to show that differing relational or epistemic properties do not block identity, addressing a Leibniz's Law style objection.
The Max Black objection and topic-neutral language
31:48The hardest objection Smart considers, from Max Black, is that identifying a sensation with a brain process does not remove the real property of what the sensation is like, such as being a yellow flash. Smart replies with topic-neutral language, defining a sensation as there being something going on like what goes on when a normal percipient views an actual object, but the hosts argue the word "like" may smuggle qualia back in since it seems to require comparing subjective feels.
Inverse zombies and the parsimony of brain stuff over ghost stuff
51:07Smart considers an inverse zombie scenario, imagining a person turned to stone who still has images and pains, and argues this experience would have to be composed of something, either ghost stuff or brain stuff. He contends that the dualist hypothesis is intelligible but less economical than identifying experience with brain stuff, treating the choice between materialism and epiphenomenalism as a matter of simplicity rather than a decidable empirical question.
Disagreements
Whether Smart's topic-neutral reply escapes qualia
38:37Wes and Chris are sympathetic to Max Black's objection and doubt Smart's topic-neutral solution works, while Mark presses the point further by arguing that any comparison using the word "like" still seems to reference a private qualitative memory of past experience, which would undercut Smart's attempted translation.
Philosophers and works discussed
- J.J.C. Smart
- U.T. Place
- Is Consciousness a Brain Process? By U.T. Place.
- Sensations and Brain Processes By J.J.C. Smart.
Questions this episode answers
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What is Place's phenomenological fallacy and what mistake does it diagnose?
8:29Place argues it is a mistake to think our descriptions of experience are primarily descriptions of inner phenomenal objects on a kind of internal screen. Instead we learn to describe the real properties of things in the world first, and only later describe our consciousness of them by reference to those same external properties.
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How does J.J.C. Smart use the Max Black objection to test mind-brain identity theory?
31:48Smart treats Max Black's objection, that identifying a sensation with a brain process does not remove the real property of what the sensation is like, as his hardest objection. His reply uses topic-neutral language describing a sensation as something going on that resembles what happens when a normal observer sees an actual colored object, though he admits he is not certain this reply succeeds.
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What is the difference between correlation, causation, and strict identity in Place's argument for materialism?
2:55The hosts describe Place's view as treating these as points on a continuum, where correlation is the loosest connection, causation is tighter, and identity is the tightest, and they discuss his claim that identity statements are licensed when one level of description explains another, as with the brain explaining introspective reports.
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What is Smart's inverse zombie thought experiment and how does he respond to it?
51:07Smart considers imagining a person turned to stone who still has images and pains, which suggests experience could exist without any brain activity. He replies that such experience would still have to be composed of something, either immaterial ghost stuff or brain stuff, and argues identifying it with brain stuff is more economical than positing an extra kind of substance.
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How does the morning star and evening star example support strict identity between mind and brain?
28:55The example shows that two descriptions can refer to the same object even though a person does not know they are the same and the descriptions have different relational properties, like which one is visible at a given time. Smart uses this to argue that not knowing a sensation is a brain process does not block the sensation from in fact being identical to that brain process.