Descartes Argument 1: 1) I cannot doubt the existence of my
mind. (My mind has the property of indubitable existence?)
2) I can doubt the existence of my body. (My body does not have the property of indubitable existence?)
3) Therefore my mind has a property my body lacks.
4) If two things have different properties then they are not identical. (Leibnizs Law: the indiscernibility of identicals.)
5) Therefore: my mind is not identical with my body.
Descartes Argument 2: 1) My body is extended in space (and so
is spatially divisible). 2) My mind is not extended or divisible. 3) Therefore my body has a property my
body lacks. 4) If two things have different
properties then they are not identical. (Leibnizs Law: the indiscernibility of identicals.)
5) Therefore: my mind is not identical with my body.
The dualistic intuition: mental things and physical things are totally different.
The causal intuitions: a) causes and effects must occupy the
same domain / be relevantly similar;
b) the physical is causally closed. The solution to this tension? Epiphenomenalism: the view that
mental events have no causal impact on physical eventsthat the physical would continue just the same even if the mental changed or ceased to exist.
An argument for behaviourism:
1) Dualism suffers serious problems: mind-body causation; the problem of other minds
(radical privacy); implausible account of the
meaning of mental terms; bad fit with empirical
psychology. 2) Behaviourism solves or dissolves
these problems. 3) So behaviourism is a more adequate
theory than dualism.
What is behaviourism?
Logical/analytic behaviourism is a theory of the mind (rather than just a methodology). Statements containing mentalistic expressions are wholly translatable into statements containing only descriptions of publicly observable dispositions to behave in particular ways. According to Ryle, a theory of mind allows us to predict and explain human behaviour; it is not a theory of some thing or set of inner states.
Mind-brain type-type identity theory:
Consciousness (as it is experienced / introspected) is identical withexactly the same thing assome physical pattern of brain activity. NB: the is of definition vs. the is of composition (i.e., this is a contingent identity claim). Initial reason 1: Problems with
behaviourism Initial reason 2: Scientific parsimony
Mind-brain type-type identity theory: The main argument:- i) Generally we conclude that two things are
really the same thing when a) they are systematically correlated, and b) observations of one of the things explains our observations of the other. E.g. electrical charge and lightning.
ii) Our observations of the brain might systematically correlate with and explain our conscious experience (as long as we can get past the phenomenological fallacy).
iii) So consciousness could be identical with a brain process. [Tacitly: this is the only way for physicalism to be true, and physicalism probably is true, so consciousness probably is identical with a brain process.]
MULTIPLE REALIZABILITY: a) If two things are numerically identical
then it is logically impossible for one to occur without the other.
b) However, pain (and other mental states) can occur without the firing of a particular sort of neural fibre (or whatever is the candidate physical state).
c) Hence, mental states can occur without the physical states with which they are supposed to be identical and so they cannot be identical with them and so mind-brain identity theory must be false.
Role vs. occupant
Software vs. hardware
NB: Functional properties are not
A sample machine table:
State S1 State
I1 B1 S3 B1 S1 B2 S2
Input I2 B2 S1 B1 S3 B3 S1
Input I3 B3 S1 B3 S2 B2 S3
Mind as syntactic engine
Cognition = the manipulation of symbols in accordance with rules
The rules operate only on the shapes of mental symbols, but the transitions mirror semantic, rational processes.
1. Mental states are whatever play a
particular causal role (i.e. a causal analysis of mentalistic concepts).
2. The relevant causal role is specifiable only within a complete psychological theory (e.g. folk psychology).
3. That theory is subject to empirical confirmation or disconfirmation.
Some flavours of functionalism:
Machine functionalism (Putnam) Analytic functionalism (Armstrong,
Lewis) Cognitivism (modern cognitive
science, e.g. Fodor, Pylyshyn) Teleological functionalism (see later
Functional state identity theory (Putnam) vs.
functional specification theory (Armstrong)
Problems for functionalism:
1) Chauvinism (species-specific receptors and actuators)
2) Liberalism (Blockheads; Chinese rooms)
3) The inverted spectrum 4) Absent qualia (zombies)
The problem of qualia!
The anti-functionalist argument form:
i) Case X is a possible case of mental (phenomenal / semantic / cognitive) difference without functional difference.
ii) If functionalism were true then Case X would be impossible.
iii) Therefore functionalism is not true.
Blockheads = functionally the same + cognitively different
Chinese rooms = functionally the same + semantically different
Spectrum inverts = functionally the same + phenomenally different
Zombies = functionally the same + phenomenally different
Aliens = mentally the same +
functionally different (chauvinism)
The Chinese Room:
Can the mental be reduced to the physical? No: the special sciences are autonomous (Fodor)some (true, scientific) facts cannot be explained or predicted using only physics Yes(ish): multiple realizability is not an obstacle to reduction (Kim)all causation is ultimately physical causation, hence covered by physical law.
What is reduction?
a) All the laws of theory S can be translated into laws of physics.
vs. b) All the events which fall under the
laws of S are physical events and hence fall under the laws of physics.
Classical theory reduction is a), not b).
A theory reduction schema: Higher-level law: S1x S2x Bridge law 1: S1x P1x Bridge law 2: S2x P2x Physical law: P1x P2x Plus Claim NK: there are natural kind predicates in an ideally completed physics which correspond to each natural kind predicate in any ideally completed special science (Fodor).
BUT: Claim NK is false (Fodor argues). Interesting generalizations can often be made about events whose physical descriptions have nothing in common i.e. multiple realizability (our old friend). E.g. Greshams law (bad money drives out good) E.g. rewards improve learning So there are no laws of physics corresponding to laws of the special sciences.
The Physical Realization Thesis (Kim):
(i) Mental states occur in a system exactly when appropriate physical conditions are present in the system.
(ii) Causal properties of mental states are due to, and explainable in terms of, the causal properties of their physical substrates.
This, plus MR, leads to the following
conclusion: Psychology is not a science with a unified subject matter: mental states are not natural kinds. Instead, there are structure-restricted reductions of mental states.
What is Consciousness? Creature consciousness Transitive consciousness State consciousness
Phenomenal consciousness Access consciousness Self-consciousness Monitoring consciousness
The Problem of Phenomenal Consciousness
What is it like to be a bat?
The Explanatory Gap
Consciousness is a mystery. No one has ever given an account, even a highly speculative, hypothetical, and incomplete account of how a physical thing could have phenomenal states. Suppose that consciousness is identical to a property of the brain, say activity in the pyramidal cells of layer 5 of the cortex involving reverberatory circuits from cortical layer 6 to the thalamus and back to layers 4 and 6, as Crick and Koch have suggested for visual consciousness. Still, that identity itself calls out for explanation! (Block and Stalnaker 1998)
Qualia Quined Qualia are:
1. Ineffable 2. Intrinsic 3. Private 4. Immediately apprehensible in
Dennett argues there are no such things.
Intuition pumps: 1) The taste of