Philosophy of the Mind
Substance: an entity, a thing that does not depend on any other entity for its
continued existence. It has ontological independence.
1. Substances are what possess properties. Properties cannot exist without
substances.
2. Substances persist throughout changes in properties. A thinker can think a
series of thoughts.
Dualism: mind is distinct from the physical.
Substance Dualism
Substance Dualism:
– There are two fundamental kinds of substances – mental and physical.
– It claims that minds do not depend on bodies in order to exist, so minds can
exist separate from the body.
– Minds and bodies are ontologically distinct and independent.
– Interactionist theory
The Conceivability Argument
In meditations VI, Descartes presents the following argument for substance dualism:
1. I can clearly conceive existing without my body.
2. What is clearly conceivable is possible.
3. So it is possible for me to exist without my body.
4. So I am neither identical with, nor a part of my body.
5. So substance dualism is true.
– Since he can conceive (its logically possible) the mind without the body, he
argues that it is possible that they can exist independently of each other.
– If it is possible that the mind can exist without the body, we must not be
identical to our body.
– Since we are not identical to our body, our minds and our bodies must be 2
completely different sorts of substances.
Objections to the Conceivability Argument
What is conceivable may not be possible
– Descartes infers possibility from conceivability.
– Just because Descartes can conceive of his mind and body as distinct
substances, doesn’t mean that they really are distinct substances.
– Masked Man Fallacy:
1. I know who my father is.
2. I don’t know who the masked man is.
3. The masked man is not my father.
– However, (3) is false because this doesn’t show that it is possible that my father
is not the masked man.
– From my conceiving that the two people are distinct, we cannot infer that it is
possible they are distinct.
, – So Descartes argues that it is possible for the mind to exist independently of the
body, because he can conceive of its existing without the body.
– BUT this doesn’t follow, it is possible that Descartes conception of the mind is
wrong.
Descartes Reply:
– In the case of clear and distinct ideas, the inference is justified. Since the
masked man fallacy and my conceptions of my dad and the masked man are
not clear and distinct ideas, the fallacy is not an objection.
What is logically possible, tells us nothing about reality.
– Simply knowing what is logically possible does not tell us which possibility
correctly describes reality.
– Assuming that whatever we conceive is logically possible, it is logically possible
that the mind and body are distinct substances, but equally it is logically
possible that thought and extension are properties of a single substance.
Mind without body is not conceivable
– Descartes may think that the mind and the body being distinct is conceivable,
when it isn’t. He may be confused or lack relevant information.
– Logical behaviourism argues that mental states and events should be analysed
in terms of behaviour, without a body we cannot exhibit behaviour, and so
without a body there is no mind. So the mind being ontologically independent is
inconceivable.
– The general point is that we can make mistakes about what is conceivable.
Descartes reply: we cannot be mistaken about clear and distinct ideas
Counter reply: Either we cannot clearly and distinctly conceive of the mind and the
body as separate substances, or we can challenge the theory of clear and distinct
ideas guaranteeing truth.
The Divisibility Argument
– Descartes claims that the mind and body have different properties;
thought vs extension.
– If they were the same thing, they would have the same properties.
Leibniz’s Principle of the indiscernibility of identicals:
– If two things are identical, then they all have the same properties. Because
one thing cannot have different properties from itself. So, if the two
things have different properties, this proves they are not one and the same.
Descartes gives the example that the mind does not have parts and is not
divisible, whereas the body is.
Objections to the Divisibility Argument
The Mental IS Divisible
– Descartes claims that we will, think, imagine with the whole mind but in cases of
multiple personality disorder, the mind can be seen to be divided. It seems
that some parts of the mind are unable to communicate with other parts.
