substance dualism

descartes divisibility argument and criticisms

clear and distinct ideas

clear: immediately present and accessible to the attentive mind

distinct: clear and sharply separate from other ideas

so that every part of it is clear (Descartes)

mental states

phenomena that endures over time

eg feelings, desires, beliefs

or properties like processes, states, events

intention

mental state which expresses choice

specifies action chosen

specifies reason for action

intentionality

property of a mental state

directed towards an object

eg my belief that Paris is the capital of France is directed towards Paris

Leibniz’s Law

aka indiscernibility of identicals

two things w same properties are same thing

two things w/o same properties are NOT the same thing

divisibility argument

P1. My mind is indivisible.

P2. My body is divisible.

C. Therefore, I am not my body.

Descartes’ view on the mind

a thinking thing

can’t detect parts

single and complete

Descartes: why the body is divisible

dividing the body does not divide the mind

Descartes: conclusion that I am not my body

completely different

not united by parts

uses Leibniz’s Law

problem with divisibility P1

we can divide the mind

modern neuroscience

subconscious eg automatic action and unconscious eg psychotic issues

so, mind and body are the same

Descartes’ response to a divisible mind

mind is ‘functionally’ divisible

physical is ‘spatially’ which is different

function is a property and property is divisible, not mind itself

so, mind is indivisible

problem with P2 divisibility

physical substance is not infinitely divisible

modern quantum science

eg subatomic particles

so, body is also indivisible

problem with divisibility of human bodies

human states are not divisible

eg running

concept of divisibility does not apply

so, body is indivisible, same as mind

divisibility argument with criticisms

leibniz’s law

divisibility argument (P1, P2 and C)

mind is divisible

functionally divisible

body is indivisible

human states are indivisible

Hume on Descartes’ cogito

knowledge and truth FROM experience

‘ourself’ is a relation of ideas

memory + repetition + prediction

experience w/ individual thoughts, emotions, feelings and ideas

individual thinker?

not enough- just existence of thoughts

conceivability argument

P1. conceive of = logically possible
P2. conceive: mind can exist w/o body
C. possible: mind and body exist independently
P4. if X can exist w/o Y, then not identical
C. mind and body are not identical

explain conceivability P2

mind and body are clear and distinct ideas
God can make any not self-contradictory thing
God can create mind and body as different things

conceivability Cr 1 - conceivable NOT possible

• Masked Man Fallacy (conceive: seperate from father, possibly same)

• conceive of distinct NOT mean distinct

• eg conceive water NOT H20, but metaphysically impossible

Descartes reply to conceivability Cr1

• clear and distinct conception establishes possibility

• eg triangle’s angles add to 180

• masked man is not clear and distinct

• mind and body are clear and distinct

conceivability Cr2 - mind w/o body NOT conceivable

• try to imagine > floating mind > still occupies space

• if aware of surroundings > physical sense organs

• physical behaviourism (require body for behaviour and mental states)

conceivability Cr3 - logically possible NOT mean reality

• possible they are not distinct

• which one is true in reality?

physical possibility

laws of nature, actual world

logical possibility

not self-contradictory, what concept allows

metaphysical possibility

necessarily, but not analytically, true
constrained by identity and nature of things
eg water = h20, conceivable as not, but not metaphysically possible

essay order conceivability argument

• Descartes conceivability argument

• Cr1 logically possible NOT conceivable (masked man, metaphysical possibility)

• Descartes’ reply (clear and distinct)

• Cr2 - mind w/o body NOT conceivable (+physical behaviourism)

• Cr3 - possible NOT reality

subs. dual. problem of other minds

IF minds are non-physical, cannot reduce to physical

empirical science NOT > epistemic access to mind

ONLY introspection > access BUT only one mind

problem of other minds: best hypothesis

inference to the best explanation

minds

‘inner’ states of an organism that respond to the environment and cause behaviour

the argument from analogy response

Mill: mental states > behaviour

other people exhibit similar behaviour

so, similar cause (other minds)

Malcolm’s response (analogy response)

analogy is weak bc ONE case (‘my’ mind)

generalisation, weak inductive reasoning

Ayer’s rebuild of subs. dual. (other minds problem)

multiple cases, links (behaviours + states)

strengthens inductive reasoning

‘subsumed’ response

although multiple, subsumed in one mind

+ involuntary actions w/o mental cause eg hiccups

evidence for whether behaviour = involuntary is introspection (one mind)

Hume’s criticism of analogy

like effects do not imply like causes

eg dry ice or fire > smoke

weakness of inductive reasoning

conclusion is probabilistic, not guaranteed by truth of premises

sound Ps NOT > valid conclusion

alternative explanation = possible

so, cannot prove indubitably

at best, dualism can prove solipsism, not other minds

problem of other minds essay plan

• substance dualism

• argument from analogy response

• malcolm’s criticism (weak inductive)

• Ayer’s rebuild (multiple)

• ‘subsumed’ response

• ‘involuntary’ response

• Hume’s criticism

• weakness of inductive reasoning

problem of other minds thesis

At best, substance dualism can prove the existence of a separate mind and body with solipsism, but cannot prove the existence of other minds.