1. What are the missing words…
A ____________ is something that does not depend or rely on anything else to exist.
A ___________ is something that relies on a __________ to exist.
____________ dualism is the view that there are two ontologically distinct types of substance in reality – __________ and ___________.
A major proponent of ___________Dualism was ____________who believed that we could doubt everything except our existence as a thinking thing. This is known as “________ ______ _____” or “I think, therefore I am”.
He believed that because we could doubt our _______ (physical) but not our __________ (mental) it showed that they were two distinct ____________ (dualism).

2. Substance Dualism The Basics:
A substance is something that does not depend or rely on anything else to exist.
A property is something that relies on a substance to exist.
Substance dualism is the view that there are two ontologically distinct types of substance in reality – physical and mental.
A major proponent of Substance Dualism was Descartes who believed that we could doubt everything except our existence as a thinking thing. This is known as “Cogito Ergo Sum” or “I think, therefore I am”.
He believed that because we could doubt our bodies (physical) but not our thoughts (mental) it showed that they were two distinct substances (dualism).

3. Quick Detour… Why is Dualism a popular approach to the mind?
Because it fits with the table we completed below, which seemingly showed that the mental and physical have different characteristics.
Physical states
Mental states
Public
Private
Fallible
Infallible
Spatial
Non-spatial
Permanent
Transient
Follow laws
Lawless/ Anomalous
Don’t have qualia
Have qualia
Don’t have intentionality
Have intentionality

4. Key Concepts Sheet! Qualia Explanation
Qualia is the Latin term used to refer to the phenomenological aspects of conscious experience, the ‘what it is like to be’ in a certain conscious state. These properties are subjective (the inner feel of an experience): they can be thought of as our particular points of view or as our personal experience of the world around us, and, it is argued, what is subjective (conscious experience) cannot be reduced to what is objective (physical existence). We might say that while we can know everything there is to know about the physicality of another person, we cannot know what it is like to be that person.
The study of the consciousness from the first person point of view.
Key Concepts Sheet!
“This is going to suck for Bob” We may be able to observe the effect this has on Bobs body (blisters), we may be able to see the nerves firing in his brain (signifying pain) we may even hear him scream out and swear loudly.
But do we really know what it is like for Bob to feel this pain?

5. Qualia Explanation
Thomas Nagel, in an article entitled ‘What is it like to be a bat?’ claims that, in order for something to have conscious mental states, there must be something that it is like to be that thing.
For example, that bats have conscious mental states is to say that there is something that it is like to be a bat. We can deduce that, since a bat’s perceptual apparatus is very different from our own, what it is like to be a bat must be very different from what it is like to be a human being.
However, what we cannot do is to deduce, purely from the differences in physical characteristics, exactly what the mental characteristics will be. We cannot, in other words, deduce the phenomenology of a bat’s world. It seems to follow from this that qualia are private to each individual.

6. Back to Substance Dualism…
The Arguments:
Argument from doubt:
My body can be doubted.
I cannot be doubted. (Cogito)
Therefore I am not my body.
NOTE: Descartes denies using this argument and it is never explicitly written in his work.
Argument from divisibility:
I am indivisible.
My body is divisible.
Therefore I am not my body.
Argument from conceivability:
I can conceive of my body as a physical non- thinking substance.
I can conceive of myself as thinking, non- physical substance.
Therefore I am not my body.

7. Remember: Leibniz’s Law
The arguments put forward by Descartes all use a variation of Leibniz’s Law (named after Gottfried Leibniz ):
Leibniz’s Law (also called the Indiscernibility of Identicals): If two things have all the same properties, then they are the same thing (they are identical).
Conversely, If two things do not have the same properties, they are not the same thing (not identical).
This table has 4 legs.
This stool has 3 legs.
Therefore according to Leibniz’s law they are not the same thing.

8. Divisibility Argument
I am indivisible.
My body is divisible.
Therefore I am not my body.
Modern neuroscience seems to show the mind is divisible. Certainly if we remove parts of the brain we seem to remove parts of the mind (e.g. understanding words).
Perhaps the mind is divisible but that still doesn’t make it the same as the body. The body is spatially divisible – it can be broken up into pieces in space.
The mind is functionally divisible, if it can be divided it is only on the basis of it’s functions, not spatially.
There already seems to be more than one part to the mind – there are unconscious things that our mind just does (keeps us breathing / balanced) without requiring us to think about it. This seems to be obviously different to conscious thought and action.

9. Divisibility Argument
I am indivisible.
My body is divisible.
Therefore I am not my body.
Whilst my body does seem to be divisible, matter (which is the substance Descartes ultimately is discussing here) is not infinitely divisible, the smallest kinds of substance seem to be in the form of waves, force fields or packets of energy – none of which seem to be able to be broken up.

10. Divisibility Argument
I am indivisible.
My body is divisible.
Therefore I am not my body.
Some properties of the physical substance (hot/cold, rough/smooth etc.) cannot be divided. Is it possible the mind is simply a property of the physical substance like these and not a separate substance of it’s own?

11. Criticisms Summary: Divisibility: I am indivisible.
My body is divisible.
Therefore I am not my body.

12. Onto… Conceivability Argument
First, I know that everything which I clearly and distinctly understand is capable of being created by God so as to correspond exactly with my understanding of it. Hence the fact that I can clearly and distinctly understand one thing apart from another is enough to make me certain that the two things are distinct, since they are capable of being separated, at least by God. The question of what kind of power is required to bring about such a separation does not affect the judgment that they are distinct. Thus, simply by knowing that I exist and seeing at the same time that absolutely nothing belongs to my nature or essence except that I am a thinking thing, I can infer correctly that my essence consists solely in the fact that I am a thinking thing. It is true that I may have (or, to anticipate, that I certainly have) a body that is very closely joined to me. But, nevertheless, on the one hand I have a clear and distinct idea of myself, in so far as I am simply a thinking, non-extended thing; and on the other hand I have a distinct idea of body, in so far as this is simply an extended, non-thinking thing. And accordingly, it is certain that I am really distinct from my body, and can exist without it.
What argument is Descartes making here?
Can you split it into premises and conclusion?

13. Conceivability Argument
If I can clearly and distinctly conceive of the essential nature of two things as separate, it must be possible to separate them (God could do it).
I can conceive of the nature of my mind as a thinking, non-extended substance.
I can conceive of the nature of my body as an extended, non-thinking substance.
Since I can conceive of these things as distinctly separate it must be possible for them to be separate. Meaning they don’t depend on one another, therefore they are two separate substances.

14. This means they are two separate substances.
Conceivability
“Since I can conceive of the mind and body as separate it must be possible for them to be separated in reality. Meaning they are two separate substances.”
Since it is possible for each to exist on it’s own, this means they do not depend on one another.
This means they are two separate substances.
I can think of this, on it’s own, as a thinking non-extended thing.
I can think of this, on it’s own, as an extended non-thinking thing.
Since I can think of each thing on it’s own, (as they don’t share characteristics) it must mean it is possible for that thing to exist alone (without the other, even if it doesn’t in our world).

15. Critique – Mind Without Body?
Mind without body is not conceivable
Is it truly possible to think about a mind without a body? Every frame of reference we have requires senses that use physical data to tell us about the world.
In everyday life we recognise people as being the same as their bodies – our friends and family are flesh and blood bodies, not disembodied souls. Without their bodies we would not recognise them.
It seems impossible then to conceive of the mind without the body, and if this is true then it means that a mind without body is logically impossible. Premise 2 is flawed.

16. Critique – Logically Possible > Reality?
Logical Possibility does not dictate reality
Just because we accept the possibility of something does not mean that it is true in this reality.
For example: I can conceive of a flying horse and imagine how one would work, but just because it is possible in one world does not mean it is true in this world. There are natural laws that go against this happening.
Logical possibility does not mean physical possibility.
Even if we accept that is possible that the mind could exist without the brain it does not mean it is true in our world/reality.
We should not be using a priori reasoning to make empirical claims about the world and reality around us.

17. Critique – Conceivable > Possible?
The fact that Descartes can conceive of the essence of his mind being separate from his body does not show that it is actually possible to separate them.
It is possible Descartes is mistaken, is missing some crucial information or has simply misunderstood the essence of his mind.
This leads on to the famous “masked man fallacy”.
Descartes invited commentary from the scholars of his day, one Antoine Arnauld raised a criticism that he felt the need to address:
The criticism was levelled at Descartes first premise that what is conceivable is always possible.
To demonstrate his issue he offered a parallel argument using Pythagoras’ theorem.
Someone ignorant of Pythagoras might well suppose that they could conceive of a right-angled triangle that lacked this property, but it wouldn’t follow that is it actually possible for this triangle to exist. Not even God could create it.

18. The Masked Man Fallacy…
“Suppose you go to a masquerade ball and you meet a charming man. You don’t know who the masked man is, but someone suggests that it could be your father. But you say “Of course it isn’t, I know who my father is and I don’t know the masked man”, so you can’t conceive of the masked man being your father.”
Does this mean your father is not the masked man?

19. Critique – Masked Man Fallacy?
I know who my father is.
I do not know who the masked-man is.
The masked-man and my father have different properties.
The masked-man and my father are therefore two distinct different things.

20. Critique – Another Way? Lois Lane believes that Superman can fly.
Lois Lane does not believe that Clark Kent can fly.
Therefore Superman and Clark Kent are not the same person.
Descartes makes this mistake when he assumes that his “clear and distinct idea” of the body and mind as separate things is enough to show that they must be separate.
His idea is a property of him, not a property of the thing he is considering.
We cannot automatically assume that subjective knowledge of something (or even a group of things) is enough for making accurate, non- contradictory statements.
What we believe is a property of us, not the thing in question therefore we cannot make accurate statements based purely on our subjective knowledge.

21. Conceivability Argument
If I can clearly and distinctly conceive of the essential nature of two things as separate, it must be possible to separate them (God could do it).
I can conceive of the nature of my mind as a thinking, non-extended substance.
I can conceive of the nature of my body as an extended, non-thinking substance.
Since I can conceive of these things as distinctly separate it must be possible for them to be separate. Meaning they don’t depend on one another, therefore they are two separate substances.

22. Finally – Mind = Brain
We’ve already seen a video in which changing the brain in some way seems to change the mind. This seems to suggest that the mind categorically depends on the brain in some way, that we cannot conceive of them separately.
Descartes would not have been aware of such a link as research into brain function would not be carried out until much later.
If we can’t conceive of a separate mind, this argument seems to fail.

23. Mini-Test – Substance Dualism
Define the term “qualia”. (3 marks)
What is Leibniz’ Law? (3 marks)
Outline the argument from divisibility in support of Substance Dualism. (5 marks)
Outline the argument from conceivability and clearly explain one issue with the argument (12 marks)
Extension: Plan an essay response to the statement “Substance Dualism is an effective theory of mind.” Do you agree?

24. Something to think about – Am I a substance?:
For my part, when I enter most intimately into what I call myself I always stumble on some particular perception or other, heat or cold, light or shade, love or hatred, pain or pleasure. I never can catch myself at any time without a perception, and never observe anything but the perception - Hume
Hume as an empiricist believed we could only know to be true what we experience. He did not think we experienced “ourselves” as existing things, instead he thought we simply experienced various individual thoughts, emotions, feelings and desires. For Hume this was not enough to show the existence of a thinker just the existence of these individual mental events.
Even if we go as far as stating that each thought, emotion or desire must have a thinker there is nothing to suggest that they all come from the same one, Descartes simply assumes that they must do.
Similarly, if Descartes wants to state that we are only indubitable as long as we are thinking then what about those times at night when we stop thinking consciously? Do we simply drop out of existence? What is keeping us persistent from day to day? For us to be an indubitable substance, we need more than just thoughts.