Physicalism Mind/Brain Identity Theories

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Designed to overcome the issues of causation with Cartesian Dualism - how the metaphysical can affect the physical (mental states having affect on the body) and similarly how the physical can affect the metaphysical (ingesting hallocinogenics)

Physicalsm is the view that all that exists is physical - that which possesses extension

Type-type identity theory suggests:

Mental phenomena are identical to certain physcial phenomena

Ergo

Having a mental state consists of being in a particular physical state

Pain = C-fibres firing

=

Reductive -

Identity theory reduces mental states to physical states

As the pain I am feeling now is identical to C-fibres activity the pain I was feeling yesterday is also identical

Pros:Simple

Occam's Razor

No need to account for relationship between physical and metaphysical - they are the same

Science based

Weaker version of type-type

Every token of one type will be identical with a token of the second type

Timepiece Analogy

Various tokens of the timepiece can be found on people's wrists, mantelpieces, town halls etc.

Every token of the timepiece will be identical in terms of physical parts designed to tell the time

However there is no single type of arrangement

Could be digital, analogue etc.

Type-type applies in the case of scientific identities - water is always H2O

Unduly restrictive in terms of mental states as it implies that mentality must be confined to human biological systems. What about Washoe?

Multi-realisability of mental states:

In the case of stroke victims a mental function lost through damage to a particular area of the brain is sometimes reinstated when a different part of the brain takes over

Like how information can be stored in different forms: hard or floppy disks

Too Reductive?

Hilary Putnam - 1967

Finding the cocktail of chemicals that relates to pain in humans is too narrow - it only works for humans

Octopus brain may be completely different to human brain

Octopus probably feel pain though

Leibniz's Law

1. Brain States and processes have spatial location

2. Mental States and processes do not have spatial location

3. Therefore mental states and processes cannot be brain-states and processes

What is it like to be a bat?

Thomas Nagel 1974

Mental states are private

Bats have very different mental states to humans

We can only speculate about what it is like to be a bat

From the outside brain states appear to be physical processes whereas from an internal prospective they will be experiences as states of mind

Impossible to avoid a duality of properties

Intentional Mental States

Most mental states possess intentionality

I cannot just believe - I must believe something

Propositional 'that' clause - 'I believe that...'

Type-Type

Token-token

Problems with both Mind/Brain Identity Theories