Dualism Flashcards
(15 cards)
substance dualism
the view that humans are composed of two types of substance: mind and matter.
Descartes defined a substance as something that can exist on its own and that doesn’t depend on anything else.
He famously argued that mind and body were two separate and distinct substances, or things.
Substance dualism says that both body and mind can exist independently of one another.
This allows for the possibility of the mind continuing to exist after the body dies.
Leibniz Law
If two things share all the same properties, they must actually be one thing.
If two things do not share all the same properties, they must be distinct things.
indivisibility argument
Descartes believes that the mind is indivisible. Different aspects of consciousness are not parts that can be removed from the mind.
Descartes believes that the body is divisible.
By their nature, bodies are divisible.
So minds and bodies are quite different.
P1: My mind is indivisible
P2: My body is divisible
C: My mind is not my body
indivisibility argument: p1 challenged
Perhaps the mind is in fact divisible.
There are examples that suggest that this is the case - Multiple Personality Disorder (MPD) and also the unconscious: people may believe or desire one thing consciously and the opposite thing unconsciously.
indivisibility argument: p1 challenged response
The way that the mind is divisible is quite different from the way that the body is.
When we say that the body is divisible, we mean that it is spatially divisible, i.e., it can be divided into different spatial locations. When we say that the mind is divisible the different parts of the mind are doing different things - they are not actually in different locations.
This is referred to as functional divisibility and is nothing like the spatial divisibility that Descartes was referring to.
Because of this, it is still possible to claim that the mind is indivisible in a way that the body isn’t.
indivisibility argument: P2 challenged
Perhaps not everything that we think of as physical is divisible. The smallest physical particles are best understood as packets of energy or force fields. These are things that cannot be divided.
This suggests that divisibility is not an essential property of physical things.
If so, then it is incorrect to claim, as Descartes does, that divisibility is an essential property of physical things.
indivisibility argument: P2 challenged response
Although in reality, we cannot divide matter further and further, this does not mean that there is a logical limit to its divisibility.
In principle, physical things/matter/body can be divided indefinitely. It’s just that in reality they can’t.
indivisibility argument: general challenge
Has Descartes made an unjustified assumption?
Descartes has from the beginning assumed that the mind must be a substance. But why must this be the case? Perhaps minds are not ‘things’ at all. Perhaps they are properties of the brain.
A property is something possessed by a substance. They depend on substances to exist. Solidity, for example, is a property that depends on a substance being solid. Temperature is a property that depends on the movement of particles that a substance contains.
These properties are indivisible and are yet undoubtedly physical.
Perhaps mental properties are properties of the brain, in much the same way as temperature can be a property of the brain. In this way, mental properties could be indivisible and physical at the same time.
physical possibility
it can happen without the laws of physics being broken
logical possibility
there is no logical contradiction involved in imagining it, regardless of whether it is physically possible or not.
We can decide what is logically possible a priori, i.e. without reference to experience.
So anything that is logically impossible involves a contradiction.
metaphysical possibility
there is a ‘possible world’ in which something could be the case. it must be logically possible, i.e., involve no logical contradiction.
conceivability argument (without reference to God)
P1: It is conceivable [logically possible] that the mind can exist without the body.
C1: Therefore, it is [metaphysically] possible that the mind can exist without the body.
C2: Therefore, mind and body can exist independently of one another.
C3: Therefore, mind and body are different substances
This argument works because Descartes has clear and distinct ideas about the nature of the mind and of the body.
Conceivability argument: response (1)
P1 is incorrect:
Mind without body is not conceivable
Imagine being a disembodied mind. How would you see, hear, move about without a body? It seems inconceivable.
If philosophical behaviourists are correct, mental states are dispositions to behave. Without a body, such behaviour would make no sense.
Conceivability argument: response (2)
What is conceivable (logically possible) may not be metaphysically possible. It is possible that something could be analytically true (i.e., its existence would not involve a logical contradiction), and yet its existence is metaphysically impossible.
This would mean that the move from P1 → C1 cannot be made.
Conceivability argument: response (2) possible responses
- Descartes refers specifically to clear and distinct ideas.
- The example of Batman and Bruce Wayne does not involve clear and distinct ideas. I do not see clearly and distinctly that Bruce Wayne is not a caped crusader.
- Equally, I do not have a clear and distinct idea that ‘water is H2O’ is not an analytic truth.
- It is different with the mind and body. Descartes does have a clear and distinct idea about their different natures.
