The mind & body are
two distinct and
independant substances
contingently connected
in a causal relation.
Causual relation - mental states affect
bodily events in a causal way and vice versa.
Substance - bearer of
properties, not itself a property.
Contingent connection - one that
happens to hold but does not have to.
Nature of Mind & Body (Descartes) - Minds and mental
states have a special epistemic status. We have private and
privileged 1st person access to our own minds; only we can
know our minds. My awereness of my own mind is infallible
and incorrigible. In contrast, our bodies are public and
knowable in the 3rd person, so neither infallible nor
statements about them incorrigible.
Arguments in Support of SD and Critical Analysis.
LEIBNIZ'S LAW. X=Y iff every property of X is a
property of Y and vice-versa. George Orwell and Eric
Blair are one and the same person because they
share all the same properties. Descartes attempts to
show that the mind and the body are separate
substances by attributing properties to one that are
not properties of the other.
ARGUMENT FROM DOUBT.
i) I cannot doubt the existence
of my mind. ii) I can doubt the
existence of my body.
Therefore, my mind and body
are two distinct things.
THE PRIME MINISTER ARGUMENT. David Cameron wakes up
with amnesia. i) I cannot doubt that I am David Cameron. ii) I can
doubt that I am the Prime Minister. Therefore, David Cameron is
not the Prime Minister. The premises are true, but the conclusion
is not. The major flaw in the argument from doubt is that it seems
to be referring not to the objects in question, but what we are
able to think about the objects in question (illustrated by the PM
argument). We must refer to the objects themselves.
ARGUMENT FROM DIVISIBILITY.
i) My mind is essentially
nont-extended and indivisible. ii) My
body is essentially extended and
divisible. Therefore, my mind is not
the same as my body.
ASSESMENT OF ARGUMENT FROM DIVISIBILITY.
Minds and mental states are not divisible only in the sense
that concepts of divisibility and indivisibility cannot be
applied to minds and mental states. Illustration: A pen on a
table is in a state of stability; it makes sense to talk about
dividing the pen, but no sense to talk about dividing the
state of stability. Similarly, the concepts of divisibility and
indivisibility have no application to mental states, so it
doesn't make sense to talk of 'divisibility' in this context.
Initial Problems
MANY MINDS PROBLEM. If X is a distinct entity, it
makes sense to ask 'how many Xs are there?'. If
minds distinct, non-physical entities contingently
related to bodies, the question 'how many minds are
in the room' makes sense. But there is no criteria
available for differentiating and individuating
non-physical minds. We cannot simply count
bodies; the connection is only contingent; bodies
can exist independently of minds.
EVOLUTION. Cartesians draw a clear distinction
between physical creatures that are minded and not
minded (humans vs. animals). Evolution makes this
'all or nothing' distinction appear incredibly
misguided; there is no such clear cut definitions
between us and animals. It seems much more
plausible to regard possession of a mind as a
spectrum. Even if there was a sharp distinction to be
made, the question of when in the evolutionary
shceme do minds come into existence, how they
come into existence, and for what reason they came
into existence, remains a complete mystery.
ARGUMENT FROM SCIENCE. The scientific method is widely
accepted and hugely successful, yet Cartesian minds are beyond the
explanatory net of science and as a result completely inexplicable in
scientific terms. It is not that science has yet to explain it, it is that
science will never be able to explain it in principle. Science is
concerned, by definition, with what is observable and testable on an
objective, empirical level in the physical world. In addition: Dualism can
tell us very little about the mind (explanatory impotence), whereas the
supposition that the mind is physical (i.e. brain) can explain a great
deal. The strong correlation between mental and physical events (or
even stronger; a neural dependence of mental phenomena on events
in the brain), the assumption that the mind is physical brings our
understanding of the mind more in line with our understanding of
everything else, and would give us more explanatory power in both
practice and principle.
The Problem of Interaction
How do the mental and physical
causually interact? Mental events
cause physical events and vice
versa (eg. my pain causes me to
wince, my belief that I am in danger
makes me run). Yet how this
interaction takes place is a
mystery.
THE PHILOSOPHICAL PROBLEM: How can a non-physical,
non-spatial thinking substance have any causal effect on physical
matter? Interaction must take place somewhere, but if the mind has
no spatial properties then it can't take place anywhere. Descartes
suggested that the interaction takes place in the pineal gland, but this
response (even if it were anatomically correct, which it is not), does
not solve the problem, but merely pushes it a stage backwards; how
does the mind interact causually with the pineal gland? Causal
relations are established through public observation; but this
apparent interaction takes place in private, so the usual method of
establishing causual relations by experiment and observation is
unavailable.
SCIENTIFIC PROBLEM: Substance Dualism conflicts with the
causal closure of the physical, an important law at the centre of our
understanding of the laws of nature. Only physical events can bring
about other physical events because, for anything to cause a
physical object to move, or cause a change in one, there must be a
flow of energy/transfer of momentum from cause to physical object.
But an un-extended mind outside of the physical space lacks the
mass and velocity necessary to do this.
DUALISTIC RESPONSE; EPIPHENOMENALISM.
Deny the existence of mental causation. Mental
states are causally produced by the brain and are
dependant on brain states, but are causally inert in
relation to the brain so have no causal effect on the
physical body. Steam engine analogy - the steam is
merely an epiphenomenon of the train; in the same
way mental states are epiphenomenon of the brain.
PROBLEMS WITH EPIPHENOMENALISM: 1) Our own experience as agents acting in the world -
Crossing the road to get a drink from a shop; part of the explanation for my actions references my
beliefs (that the shop sells drinks) and desires (I am thirsty) in what appears to be a causal
explanation. 2) Cannot get rid of the idea that other people's minds have made a difference in the
physical world through their causal effect on behaviour (eg. beleifs about the universe's origins
cause physicists to perform experiments). 3) Epiphenomenalism is incoherent and creates a
paradox. By saying 'I believe that epiphenomenalism is true' that presupposes that the person's
beliefs are causally active - they produced verbal behaviour! One abandons the doctrine of
epiphenomenalism in asserting one's belief in it.
The Problem of Other Minds
If the mind is essentially private, then there are problems
concerning how we can ever come to know 1) what anyone
else is thinking, feeling etc. 2) whether there is any thinking,
feeling etc. actually going on in other people. If Cartesian
minds are non-physical and beyond the realm of physical
detection, but as a 3rd person we are only ever aquainted with
the physical, how do we know (both in practice and principle)
that these minds exist?
MILL'S RESPONSE: We infer from our own
experience of our own minds. i) People exhibit similar
behaviour to me, and ii) my behaviour is caused by
underlysing mental states. iii) Therefore, their
behaviour is similarly caused by underlysing mental
states.
PROBLEMS WITH MILL'S RESPONSE: 1) How can
we ever reasonably generalise from a single case?
Weakes example of an inductive argument possible. 2)
It is only the behaviour of other human beings that is
sufficiently similar to our own that makes this analogy
possible. Non-human animals can surely be minded? 3)
Our awareness of other minds is immediate and more
certain than this analogy suggests. Our conviction is
strong, and doesn't necessitate the analysis of other
people's behaviour to deduce that they are minded.
WITTGENSTEIN'S PRIVATE LANGUAGE ARGUMENT: Problem of other minds
stems from a misunderstanding of language. The existence of a private
language would require private, inner ostensive definition and privately
following a rule. The first is required to fix the meaning of a term, and the
second to use the term correctly. Neither of these is possible. In order to fix
the meaning of a term privately, I must have a criterion of correctness. But
this criterion cannot be drawn privately; whatever seems right to me, is right,
so it makes no sense to talk about being right. There is no possibility of an
independent check with a private language so we cannot learn mental
vocabularly privately, from the 1st person pov.
One can never introduce into a public language a word which refers (in that
language) to a private object, and the private object simply becomes irrelevant. The
nature of mental states could be completely different, but we use the same words
and actions to describe and capture it, so any mental states or events that are
private are irrelevant to the meaning of the words used in relation to minds. Words
like 'pain' and 'love' are defined by public criteria.
If there can be no private languages, as set out above,
and yet we can use mental vocabulary (as we certainly
can and do) this proves that other minded persons exist.
Therefore, asking the question of whether other minds
exist is self-defeating. Wittgenstein doesn't solve the
problem; he dismisses it.
IMPLICATIONS: 1) Solves the problem of other minds. 2) Undermines some
of the most basic assumptions of Cartesian dualism. PLA undermines
assumption of minds' epistemic 1st person status; what you can be said to
know and say about your mind remains always public. 'inner feeling' etc - we
cannot be said to KNOW these things. Wittgenstein says that it makes no
sense to talk about 'knowing' things like sensations - 'I know I'm in pain' just
means 'I am in pain'. Pain is not descriptive but is rather expressive in nature.
'knowing' entails the possibility of doubt and I cannot doubt that I am in pain.
Consequently, I cannot be said to know my own mind privately.