Philosophy of Mind
I. The Problem(s) of Other Minds
A. The First Problem: What justification do we have for believing that other minds exist.
1. The Cartesian legacy: The ghost in the machine
a. Minds are non-physical centers of thought & consciousness linked to physical bodies.
b. How do we know that other bodies have ghosts (= minds)?
2. Unique (?) features of minds
a. Consciousness: sensations, pains, pleasures
b. Intentionality: representing (or mis-representing) the world as being a certain way.
3. Robots and Zombies: Something could behave a lot like a normal human although it was not conscious and did not have any intentional states.
B. The Second Problem: What justification do we have for our beliefs about the nature of other people’s conscious experience?
1. We often think we know what other people are experiencing.
2. The problem of the inverted spectrum.
C. The argument from analogy and its weakness
1. Russell’s principle: Similar causes probably have similar effects.
2. Objections
a. Induction from a single case is very weak.
i. Compare: Testing the effectiveness of a drug on a single subject because it is impossible to observe the effects of the drug on any other person.
b. The increasing plausibility of the idea that we will be able to build life-like robots.
D. Metaphysics and epistemology (again). In attempting to explain how we can have knowledge of the external world, many philosophers were led to propose metaphysical theories about the nature of the external world. (Berkeley is a clear example of this.) Much the same has happened in the philosophy of mind. In an attempt to explain how we can know about other minds, philosophers have proposed metaphysical theories about the nature of minds.
II. Behaviorism
A. In psychology: Disillusion with studying consciousness through introspection, psychologists proposed a methodology that focused on collecting data about behavior.
B. In philosophy: Behaviorism emerged as an attempt to solve the problem of other minds.
1. The linguistic version of behaviorism: Claims about mental states can be translated into claims about how people would behave in various actual and hypothetical circumstances.
a: Example:
‘Tom has a toothache’ means
i) Tom holds his jaw.
ii) Tom moans.
iii) If you touch the tooth, Tom will scream.
iv) If you ask Tom, "Do you have a toothache?" he will say "Yes."
v) etc.
2. The metaphysical version of behaviorism: Mental states just are complex behavioral dispositions.
C. Objections to behaviorism
1. The circularity problem in behaviorist definitions
2. Identically behaving people can have very different mental states.
a. Dennett’s example of curare and "amnestic"
III. Functionalism and the Computer Model of the Mind
A. Getting internal states back into the account of the mind
1. The identity theory: mental states are brain states
a. Every kind of mental state is identical with a kind of brain state.
2. The chauvinism problem: This theory makes "alien" mentality impossible.
a. Creatures that do not have a carbon based chemistry could not have thoughts.
B. Functionalism (Armstrong, Lewis, Fodor)
1. Mental states are states that play a characteristic (and typically very complex) causal role in mediating between stimuli (or "input") and behavior (or "output").
a. A solution to the chauvinism problem: The same causal pattern can be realized in many different kinds of physical systems.
2. The analogy with computer programs
3. The central idea of functionalism: Mind is to Brain as Program is to Computer
a. The central metaphor of cognitive science
C. If functionalism is correct then a properly programmed computer would have real mental states (with real intentionality and real consciousness).
1. Comparison with behaviorism: Functionalism does not claim that anything that behaves in the way a person does had real mental states.
D. A problem for functionalism: Searle’s "Chinese room" allegedly shows that functionalism is too "liberal" – it attributes mental states to things that don’t have them.
1. The set-up
2. The claim: No part of the system understands Chinese.
a. Thus understanding (an important kind of mental state) is not a functional (or program) state.
3. Extending the argument to consciousness
a. Let the Chinese room control a robot that acts as though it is feeling pleasure or pain. This system would not really be conscious.
4. Searle’s view: Consciousness and intentionality are caused by biological systems (and perhaps other kinds of systems as well).
a. An objection: This view leaves us with the other minds problem. There is no way of knowing whether some alien creature (or artifact) causes real intentionality and consciousness.
IV. Puzzles of Consciousness
A. Physicalism
1. What it claims
2. Why it is attractive
a. The progress of science
i. The demise of vitalism in biology
ii. There seem to be no causal gaps in the physical causal chain between stimuli and behavior.
3. If all causation is physical then either consciousness must be some sort of physical phenomenon or else consciousness is epiphenomenal.
a. An event or state is said to be epiphenomenal if it is at the end of a causal chain: It has one or more causes, but it caused nothing at all.
B. Challenges to physicalism
1. Jackson’s Mary
a. Even if Mary knows all that can be known about the physics (& chemistry and biology) of color vision, there is something that she does not know until she actually sees red for the first time.
2. Nagel’s bat
a. No amount of physical, chemical or biological knowledge can tell us what it is like to be a bat.
3. Limits to human knowledge?