substance dualism Flashcards
what is substance dualism
Substance dualism is the belief that there are two ontologically distinct substances (minds exist and are not identical to bodies or to parts of bodies), mental (ones which only exist in time, and are thinking and indivisible) and physical (those extended in space and time and are unthinking and divisible).
outline the indivisibility argument
P1) The body (matter) has parts and can be divided as it is extended in space
P2) The mind is singular and cannot be divided as it is not extended in space
P3) According to Leibniz’s Law, if two things are identical then they have all the same properties, if even one property is different then they cannot be identical
C1) Therefore, since they have differing properties of being divisible or not, they are not identical, and are two ontologically distinct substances
give 4 examples of how the mental is divisible
- brain damage –> Phineas Gage
- mental illness –> DID, schizophrenia
- split brain research –> epilepsy treatment of splitting corpus collosum
- psychological theories such as Freuds Id which says there are certain parts of the mind we are not conscious of
how could Descartes respond to the objection to the indivisibility argument that the mental is divisible
- could argue there is a distinction between spatial and functional divisibility
- spatial divisibility involves physical separation, which is not possible for the mind as it is not physical
- functional divisibility involves parts of something being responsible for different things
not implying extension and therefore it is conceivable that mind could be divisible in this way
explain the first version of the objection to Descartes indivisibility argument, that not everything thought of as physical is divisible
- version 1 = physical objects cannot be infinitely divided
- if matter is divisible, according to Descartes, then we should be able to go on dividing infinitely
- but according to physics atoms cannot be divided past protons neutrons and electrons so this undermines Descartes understanding of matter making his argument incorrect as the physical may not be fully divisible
If either of these are true, then Descartes’ conception of matter as indivisible cannot be true.
It also means that mind and matter may in fact share a feature - indivisibility - meaning Leibniz’s Law could be used to argue that they are in fact the same substance.
explain the second version of the objection to Descartes indivisibility argument, that not everything thought of as physical is divisible
version 2 = physical properties cannot be divided
- alternatively we can talk of features and properties of physical objects
- the body has an ordinary temperature which is part of our physicality, 37 degrees, this cannot be split into two temperatures of 18.5 degrees
- also we cannot divide the wetness of an object, it is either wet or not
- this too seems to contradict Descartes understanding of matter
If either of these are true, then Descartes’ conception of matter as indivisible cannot be true.
It also means that mind and matter may in fact share a feature - indivisibility - meaning Leibniz’s Law could be used to argue that they are in fact the same substance.
outline Descartes conceivability argument
p1, p2, p3, p4, c1
P1) I can conceive of a clear and distinct idea of my mind as a thinking and non-extended thing and my body (matter) as an extended, non-thinking thing
P2) Anything I can conceive of is logically possible
P3) Leibniz’s Law
P4) If it is logically possible that mind exists without body (matter), then mind is not identical to the body
C1) Therefore, mind and body exist independently of one another as two ontologically distinct substances
what does logical possibility mean
conceivable and not self contradictory –> true analytic and synthetic statements
what is physical and metaphysical possibility
physical = what can happen given the laws of nature
metaphysical = constrained and relating to the fundamental nature of things –> logically possible (conceivable) that water is not H2O but it is not metaphysically possible since water simply is H20
explain the objection to the conceivability argument that mind without body is not conceivable –> physicalism
- if something is conceivable then it is intelligible, meaning we can articulate it conceptually and it is not self contradictory
- physicalism claims that only one substance exists, which is the physical, including matter and non-fundamental things such as forces
- a physicalist understands mind in a physical way, often as the brain and sometimes also as the body, this means that to have a mind means necessarily to have some kind of body, so it is not conceivable for mind to exist distinct to matter
- arguments in favour of physicalism
what is the masked man fallacy and link to argument that what is conceivable may not be metaphysically possible + Descartes
- a logical fallacy where one misapplies Leibniz’s Law
I know that batman is a caped crusader
I know that Bruce Wayne is a playboy millionaire
Batman is not Bruce Wayne - Descartes claims that mind and matter do not share the same properties when in fact they could
- Descartes would argue that his concepts of mind and matter are different as they are clear (self evident) and distinct (cannot be confused with other ideas)
- they cannot be mixed up like one could mix Bruce Wayne and Batman up
explain the objection to Descartes conceivability argument that what is metaphysically possible tells us nothing about the actual world
- just because we can conceive of a mind distinct from matter does not mean it is actually possible
- example of water and H20 being distinct when it is metaphysically impossible
- all Descartes has done is conclude that it is metaphysically possible for mind and matter to be distinct however he does not rule them out being the same
- so he needs to argue that it is metaphysically possible for mind to be the same as matter, then rule out the possibility of a logical/identity sense
what two other theories can be applied to Descartes arguments
Hume copy principle –> we cannot have an impression of the mind without body, so it is not conceivable
Ayer verification principle –> Descartes claims about the mind are meaningless, they are neither analytically nor empirically verifiable
what is interactionist dualism
The claim that mind and matter are distinct substances that can interact. They can causally influence each other, the mind can exert causal influence over matter and matter over the mind
outline the conceptual interaction problem P1-5, C1
P1) Bodies interact with one another by exerting force
P2) Exerting force requires extension
P3) If the mind is non-extended then it cannot exert force
P4) If substance dualism is true, then the mind is non-extended and cannot exert force
P5) However, the mind can exert force on bodies
C1) Therefore substance dualism is false
outline the empirical interaction problem
1) The law of conservation of energy says that energy cannot be created or destroyed —> only transferred
2) Our universe is a closed system
3) If substance dualism is true then that would mean that energy is constantly being added into the closed system each time the mental interacts with the physical
4) So, if substance dualism is true, the the law of c of e is false
5) There is lots of empirical evidence for the law
6) So substance dualism must be wrong
how does Descartes respond to the conceptual problem of interaction
he claimed that the mind does not immediately and directly interact with all of the body, only the pineal gland in the brain
- the issue with this claim is that this is still a physical thing and so does nothing to solve the conceptual problem of interaction
what is the problem of other minds
this is a form of scepticism that undermines our usual justifications for claiming that those other than ourselves have minds
we have intimate access of our own minds but only empirical access to the minds of others
we can observe bodies and behaviour but do not have access to inside their mind
difference between first and third person viewpoint of the mind
why does substance dualism lead to solipsism
Descartes establishes his cogito that he can be certain that he exists as a thinking thing but he fails to prove God and the external world
- he cannot know that other minds exist, this could be a trick by the evil demon
outline Mills argument from analogy P1-4, C1
P1) I have mental states of certain kinds
P2) For me, my mental states are caused by certain kinds of inputs and cause certain outputs –> I stub my toe and shout ouch
P3) Other bodies have similar kinds of outputs –> I see them stub their toe and they shout ouch
P4) Similar effects often have similar causes and similar causes are often the result of similar effects
C1) Therefore, other bodies are likely to have minds with mental states of similar kinds to mine which are caused by those inputs and cause those outputs
what is an argument from analogy and what is the main weakness these arguments face
- an inductive argument that relies on making a comparison of one thing to another to the effect that they are similar
- they succeed based on how appropriate and convincing the analogy is
- their main weakness is when the analogy is not very strong
- also weak as the argument relies on only one case
what is an abductive argument
- a form of inductive argument that involves an inference to the best explanation
- Russels best hypothesis can be applied to substance dualism that the existence of other minds is the best hypothesis
explain Gilbert Ryle’s objection that dualism makes a category mistake
- category mistake is a logical error of assigning a concept to a logical category that it does not belong to
- dualism assigns the concept of a mind to the category of substance
- for him, the mind is not an object over and above the body, it makes no sense to assume that we can meaningfully talk about something non-physical that cannot be investigated scientifically
- in the same way that universities do not refer to anything separately existing to the buildings
