Philosophy of Mind

Philosophy of Mind • Dualism: in addition to the physical/material body, there is an immaterial mind • Physicalism: mind and body are both entirely physical

Dualism • Substance dualism: • The mind is an immaterial substance, i.e., a thing that can (logically possibly) exist by itself • Property dualism: • certain mental phenomena (states, events, etc.) are immaterial properties of some material thing (e.g., brain, body)

Brie Gertler In Defense of Mind-Body Dualism

Disembodiment Argument 1. I can conceive of experiencing this pain while disembodied 2. What is conceivable is possible 3. It’s possible that this pain exists in immaterial being (1, 2) 4. If this pain were a physical state or event, it couldn’t exist in immaterial being 5. So, this pain is not identical to any physical state (3, 4) 6. So physicalism is false (5)

Who cares? • pain : C-fiber firing : : water : H2O • Pain is either necessarily physical or not physical at all • Analogously for other mental phenomena • Since mental events are not necessarily physical, they aren’t physical • So we are not entirely physical

Physicalism • Behaviorism: • What we call mentality is really just proneness to behave in certain ways • ‘x is in pain’ means: ‘x is disposed to cry out, wince, etc.’ • Functionalism: • Mental states are functional states of a complex system • Pain is any state that plays a certain causal role: e.g., is produced by kicks and shocks, leads to fear, aversion, pain behavior, etc. • Identity theory: the mind is the brain • Pain is (but doesn’t mean) C-fiber firing, or brain state #71325, or whatever we discover it to be • Like ‘water is H2O’ or ‘lightning is electrical discharge’, a scientific discovery, not a fact about meaning

Peter Carruthers The Mind is the Brain

Causal Argument • Some mental events cause physical events • Every (caused) physical event is wholly caused by some physical event • Therefore, some mental events are physical events • Plausibly, if they’re physical events, they’re brain events, and if some are, all are

Arguments for Premise 2: • Conservation laws of physical sciences • Metaphysical principle of the ‘causal closure of the physical’ • Neuroscientific induction

Objections to Physicalism:Certainty Leibniz’s Law: if a is numerically identical with b, then a cannot have any properties that b lacks • I am absolutely certain of having certain conscious states • I am not absolutely certain of having certain brain states • Therefore, these conscious states are not identical with these brain states (by Leibniz’s Law)

Response: • Leibniz’s Law does not hold in “intentional contexts” • “intentional”: having to do with meaning • ‘Jocasta is pretty’ implies ‘Oedipus’s mother is pretty’ • ‘O said that Jocasta is pretty’ does not imply ‘O said that O’s mom is pretty’ • ‘O thought that J was pretty’ does not imply ‘O thought that O’s mom was pretty’ • ‘I can tell I’m in pain’ does not imply ‘I can tell I’m in brain state #714390’, even if pain is brain state #714390

Objections to Physicalism:Color, etc. • An afterimage may be green (a taste sensation may be sweet, etc.) • Brain events aren’t green (or sweet, etc.) • Therefore, afterimages (etc.) are not brain events

Response: • Note first how this applies to dualism as well: the immaterial soul isn’t green either…. • The afterimage isn’t green in the sense that grass is; it’s an experience of green, not a green experience.

Objections to Physicalism:Spatial properties • Brain events are spatially located • Mental events are not spatially located • Therefore, mental events are not brain events

Response • It is unusual to attribute precise locations to specific thoughts (e.g., ‘two inches behind her left eye’), but that doesn’t make it senseless • The question is where the event is occurring in virtue of which Mary is thinking about her mother • And that event is occurring two inches behind her left eye

Philosophy of Mind