Substance Dualism

Define substance dualism.

The view that human beings consist of two kinds of substances, a mental or spiritual substance (the mind or soul) and a physical substance (the body).

Minds are not identical to bodies or to parts of bodies.

This means they can exist independently of one another and so alludes to a continued existence after death.

State Descartes indivisibility argument.

P1) My mind is indivisible.

P2) My body is divisible.

C) My mind is not my body.

What is Leibniz Law and how does it link to Descartes indivisibility argument?

If two things share all the same properties, they must actually be one thing; but if one has any property that the other lacks, they must be distinct things.

The mind (mental substance) and the body (the physical substance) do not share the same property of divisibility, therefore, they are distinct things.

What are strengths of the indivisibility argument?

1) It is clearly valid (the conclusion must follow from the premises).

2) P2 is hard to question, our bodies can be divided.

3) P1 arguably does seem to be something important about the nature of consciousness, our minds seem to have a unified nature as we experience a singular consciousness and mental states cant be thought of as having size or shape and so it makes no sense to talk of dividing them.

What is the response to Descartes indivisibility argument that the mental is divisible in some sense (experimental evidence)?

The feeling of possessing a singular consciousness, which we perceive through introspection, may be an illusion. Experimental evidence supports this idea.

Examples- severing the corpus callosum, splitting the left and right hemisphere, have unusual experience, for example both picking up an item with one hand before the other hand replaces the item, suggesting a divided mind and two conscious experiences from an original one.

Example- split brain patients have the two sides of the visual field artificially separated, information is only available to the opposite hemisphere than the eye shown. Left hemisphere shown a picture- the right hand. pressed the button and he was able to name what he saw (left hemisphere has the main responsibilities for speech), when the right hemisphere was shown a picture, the left hand would press the button yet he would report that he hadn’t seen anything. This suggests that the right hemisphere was aware of the picture but the left was not.

What is the response to Descartes indivisibility argument for substance dualism the not everything though of as physical is divisible?

What is the response to Descartes indivisibility argument that the mental is divisible in some sense (Empiricist response )?

Hume argues that when introspecting, we are not aware of a single thing which is having experiences, but rather a series of conscious experiences. If this is true, we have no immediate consciousness of a divisible self, as Descartes suggests, and so the mind is not a singular entity (indivisible).

Just because we cannot imagine being aware of two streams of consciousness at once does not mean that they cant both exist.

What is the response to Descartes indivisibility argument that not everything thought of as physical is divisible?

The idea that the mind is indivisible does not mean that it is not physical. There are physical things which we can’t make sense of dividing, for example running, perhaps we need to think of mental states alike to these. The concept of divisibility doesn’t apply to the self.

Define the actual.

The actual is the way the world (universe) happens to be, this includes all the facts of our world and universe.

Define conceivable.

The conceivable are all the ways the world might have been, consistent with the laws of thought, it is anything that you can conceive e.g a 1000 sided figure. Conceivability includes thing which are physically possible and things which are not physically possible.

Define the physically possible.

The physically possible is all the ways the world could have been consistent with the laws of physics and of our universe. This includes both the actual and non-actual e.g collyers is in Horsham and collyers is in Crawley.

Define the metaphysically possible.

The metaphysically possible is all the things that are true in some possible world.

What is the relationship between the logically possible and the metaphysically possible

Things which are conceivable are assumed to be metaphysically possible, if this is the case, we should be able to work out what is metaphysically possible purely a priori (by reflecting on whether there are any contradictions).

What is Descartes conceivability argument?

P1) If I can clearly and distinctly conceive of the essential nature of two things separately, it must be metaphysically possible to separate them.

P2) I clearly and distinctly perceive myself (my mind) to be essentially a thinking and unextended thing.

P3) I clearly and distinctly perceive my body to be essentially an extended and unthinking thing.

C) It must be metaphysically possible for mind and body to be separated, meaning that they are distinct substances.

What’s a shorter (Lacewings version) of the conceivability argument?

P1) It is conceivable that mind can exist without the body.

C1) Therefore, it is possible that mind can exist without body.

C2) Therefore, mind and body are distinct substances.

How is premise 1 of Descartes conceivability argument explained.

The mind and the body (both as substances) can be conceive of separately (the ideas is consistent with the laws of thought), therefore it is metaphysically for God to separate them.

How is premise 2 of Descartes conceivability argument explained

Introspection reveals the true nature of his mind to be thought or thinking. Descartes believes that he can conceive of himself without a body but not without thinking (a mind), he argues that he must in essence be a thinking thing.

What is the response to Descartes conceivability argument that mind without body is not conceivable

It is inconceivable for your mind and body to be separate (attacks P1), Descartes may be confused or lacking relevant information. Hume argues that we cannot have no idea of our mind or self as concepts have to originate from experiences. If we reflect on our sense experiences, there is no impression of the mind, we are aware of a collection of mental states, which are the contents of consciousness, but we are never aware of an owner of these therefore, Hume argues, it is not conceivable for them to be separate substances.

Disembodiment is not conceivable, firstly we cannot disembody ourselves and secondly it is not conceivable to be a mind without a body, in what sense could you see or occupy space.

Out of body experiences are not verifiable.

What is the response to Descartes conceivability argument that what is conceivable many not be metaphysically possible

Antoine Arnaldi attacked premise one (that whatever is conceivable is metaphysically possible). He offered a clear fallacious parallel argument to Descrates argument, that somebody who is ignorant of the the proof of Pythagoras theorem may be able to conceive of a right angled triangle which hypotenuse doesn’t equal the square root of the sum of the square of the other two sides, despite this, it is not metaphysical possible for a right angled triangle to lack this property. In the same way, despite Descartes being able to conceive of the essence of mind and body being distinct, it doesn’t guarantee that it is metaphysically possible to separate them.

What is a counter argument to the response of Descrates indivisibility argument that what is conceivable many not be metaphysically possible

It only works if Descrates conception of mind and body is incomplete and or confused, alike to the person in the example who’s idea of right angled triangles was confused. Descrates claims that his conception is not confused as it is clear and distinct

What is my evaluation of the Arnaulds response to Descrates conceivability argument

Descrates relies on his knowledge of the objects attributes which were discovered through inspection (how he can and can’t conceive them), however this means that his knowledge may still be confused r incomplete as appearances may be deceptive or incomplete. For example our ideas of heat being clear and out idea of motion being clear and distinct despite them being linked.

What is the response to Descartes conceivability argument that what is metaphysically possible tells us nothing about the actual world

Even if we accept that mind and body can be conceived of as distinct substances and so it is metaphysically possible to separate them, this doesn’t show that it is physically possible in our world. Metaphysical possibility does not entail physical possibility, in this world, the laws may prohibit consciousness from appearing without a brain to produce it,

Physicalism is conceivable alike to dualism, meaning that they are both metaphysically possible, we are not shown what is physically true in our universe.

We cannot use a priori reasoning to analyse concepts of mind and body and make substantive empirical claims off of them,

What is a response to the argument against substance dualism that what is metaphysically possible tells us nothing about the actually world.

What is metaphysically possible tells us something about how things actually are in the world because what is metaphysically impossible cannot exist. Descartes can argue that we cannot clearly and distinctly conceive of mind and body as anything other than separate substances.