Test 3 Minds and Bodies Review
The issue:
The Questions What am I? What sort of thing am I? Am I a mind that occupies a body? Are mind and matter different (sorts of) things? Is conscious awareness a physical event or something that happens in an immaterial soul?
The Landscape How many kinds of stuff? Dualism: Minds and Matter Idealism: Everything is mental Monism: Materialism: Everything is material Eliminative Materialism Identity Theory Epiphenominalism There are no mental states, just like there are no ghosts. Graziano Mental states are identical to brain states, just like water is identical to H 2 O. Qualia are causally impotent. Jackson
Descartes and Mind/Body Dualism
Descartes I can conceive of myself without a body, As a disembodied mind. I cannot conceive of myself without a mind, As a mindless zombie. So, having/being a mind is an essential property, while Having a body is merely an accidental property.
Life After Death? If there is such a thing as life after death, then there must be a part of you that continues to exist after the death of your body. So, if you believe in life after death, you are already committed to the idea that you are something distinct from your body i.e., distinct from any material object.
Descartes A Dualist Descartes thinks that what I am is a mind, and that I occupy a material body. Thinking (being conscious) is an essential property. Being extended (occupying space having a body) is merely an accidental property. So, there are two fundamental and distinct basic kinds of stuff: mind and matter.
Mind/Body (or Substance) Dualism: There are two distinct, fundamental and irreducible, sorts of things in the world MINDS Conscious Beings: Non-material beings which are the subjects of conscious experience. Descartes: Res cogitans Thinking but non-extended beings (beings that do not occupy space). BODIES (Matter) Material Beings: Material ( corporeal ) beings that cannot be the subjects of conscious experience. Descartes: Res extensa Extended beings (beings that occupy space), but are not capable of thinking.
Descartes Arguments for Dualism Bodies are divisible. Minds are not. So they cannot be one and the same thing. Mind and Matter are conceptually distinct the concept of each is independent of the concept of the other. So it is conceptually possible for one to exist without the other. So they must be metaphysically distinct.
A Problem: Causal Interaction On Descartes view (dualism), minds and bodies are fundamentally distinct kinds of things, distinct kinds of substance. And yet, he believes they causally interact with one another. Exp.: Sense perception, willful action. But it seems impossible to explain how things with nothing in common could influence each other.
Mental States and Materialism
What are Mental States? A mental state is just a state or condition some person might be in, like seeing, thinking, being in pain, willing, desiring, etc. So, thoughts, pains, desires, beliefs, etc., are all mental states. We will use this term in a neutral way, that is, without presupposing either dualism or materialism. We need to have some way of talking about these things that doesn t takes sides in the dispute.
The Options According to the dualist, mental states are states of an immaterial mind or soul. There are different varieties of materialism: According to the Identity Theory (which Carruthers supports) mental states are identical to brain states. According to Eliminative Materialism (a version of which was held my Graziano), there are no such things as mental states.
Two Varieties of Materialism: The Identity Theory: Mental states (thoughts, sensations, etc.), are identical to states of the brain and/or central nervous system: In the way in which water is identical to H 2 O, or lightning is identical to discharges of electricity in the atmosphere. Eliminative Materialism: There really are no such things as mental states ( thoughts, sensations, etc.): Like ghosts or caloric, we used to believe in them. We haven t learned what they really are (what they are identical to ): rather, we have learned that they really aren t, i.e., that there are no such things.
Carruthers and the Identity Theory
Carruthers: Identity Theory Carruthers turns a problem for dualism into an argument against it (an argument for the identity theory). 1) Only physical events can cause physical events; 2) Yet thoughts (mental states) can cause physical events (willful action); 3) So thoughts (and other mental states) must be (must be identical to ) physical events.
The Identity Theory Rejects Dualism: a variety of Materialism. Claims that everything that exists is, ultimately, material. Unlike Eliminative Materialism, accepts that mental states are, in some sense, real. But claims that what they really are are states of the brain and/or central nervous system. So thoughts (and other mental states ) are identical to brain states in just the way that water is identical to H 2 O.
Carruthers and Leibniz Law Carruthers argues that mental states are identical to brain states: dualists disagree. So, the debate concerns whether or not these things are identical. Leibniz Law states a general truth about identical things: if two things are identical, they must have the same properties. So if things have different properties, they cannot be identical.
Carruthers Rebuttals Objection: The Argument from Certainty I can be certain of mental states, but not brain states, and so they cannot be identical. C: being such that I can be certain about it is not a[n intrinsic] property that things have. Objection: The Argument from Color I can have green after-images, but brain states can t be green, and so they cannot be identical. C: After-images aren t actually green.
The Landscape How many kinds of stuff? Dualism: Minds and Matter Idealism: Everything is mental Monism: Materialism: Everything is material Eliminative Materialism Identity Theory Epiphenominalism There are no mental states, just like there are no ghosts. Graziano Mental states are identical to brain states, just like water is identical to H 2 O. Qualia are causally impotent. Jackson
Jackson, Qualia, and Epiphenomenalism
Jackson A Qualia Freak Qualia: What it s like to smell a rose, etc. There are truths about what it is like to smell a rose, etc. These are not truths of physics. So, there are truths that are not truths of physics.
Jackson s Dilemma Jackson recognizes there are truths about what it is like to smell a rose; And believes that these truths are not truths of physics. Dilemma: Doesn t claiming there are truths that are not truths of physics force one into dualism? Doesn t this force one to reject materialism?
Jackson s Solution Distinguish (mere) Materialism from (what he calls) Physicalism. Materialism: Everything that exists is material. Physicalism: Materialism plus the claim that all truths are truths of physics. Jackson is forced to reject physicalism. But accepting materialism while rejecting physicalism leaves him with Epiphenomenalism.
Epiphenomenalism What you get if you accept qualia (truths about what experience is like) while rejecting dualism. Qualia are real, but causally impotent: they are caused by physical events, but cannot themselves cause physical events. So, the world wouldn t be any different if we were all zombies. Consciousness is real but doesn t do anything.
Why can t qualia cause? According to science, all causes must be describable in the terms of physics. But qualia, Jackson has argued, cannot be described in the terms of physics (Facts about them are not facts of physics.) So, qualia cannot be the causes of physical events. Epiphenomenalism is the view that qualia real, but causally impotent. We have a conscious life, but our conscious life does not have any impact on the material world.
Mental States and Causality
Turing and Computers
The Turing Test How could we tell whether or not a computer could think? How could we tell if it was conscious? Turing proposes a test, and says if a computer could pass it, we would have to say that it thinks. The test involves answering question in a way that could fool us into believing we were talking to a human being.
Turing s Imitation Game
Turing s Claim Any computer (hardware plus software plus data) that can successfully play the imitation game i.e., one that can provide answers to our questions to it that we can t distinguish from the answers provided by a human being thinks! I have no more reason to deny that it is conscious or has inner states than I have to deny that you do.
The Argument from Consciousness The Argument: 1) Only things which are conscious (i.e., that have conscious mental states) can think. 2) Computers are not conscious (i.e., do not have conscious mental states). 3) Therefore, computers cannot think. Turing s Response: This argument simply begs the question. It simply assumes without argument that computers are not conscious. But it raises the crucial issue: on what evidence do we believe that other humans are conscious?
The Core Issue Turing s discussion of the Objection from Consciousness helps us understand the core of the issue. We cannot see inside other people s minds, and yet we believe they are conscious. So, we must believe this because of how they behave specifically, how they talk. If we judge that something thinks because of the way it talks, we must admit that computers that talk like humans think. If we insist that we must have direct access to inner mental states to say that something thinks, then we must deny that other humans think.