1
Q
the Turing test
A
- Alan Turing devised a test for determining whether a computer had achieved human intelligence
- he said that we should focus on whether we could distinguish a computer from a human, rather than metaphysical issues like consciousness
- Turing said that a computer had human intelligence if it could trick a human into thinking it was human
- Turing was not a functionalist, but this test was influential on functionalism
2
Q
metaphysics of mind
A
does the mind exist as a substance: can it exist independently, or does it depend on something physical to exist
- substance dualism: two types of substances exist - mental and physical
- physicalism: only physical substance exists, and everything that exists depends on physical substance and properties
- functionalism: we can understand the mind and mental states without making any claims about what substances exist
3
Q
functionalism
A
- mental states and properties are functional states and properties
- each mental state is a disposition to behave in particular ways and have certain other mental states, given certain inputs from the senses and certain other mental states
- different mental states differ in their typical inputs and outputs
- the complete description of the mental state’s outputs, for each possible set of inputs, is the description of its function
4
Q
causal role functionalism
A
- causal role functionalism understands the relation between inputs, the states and outputs causally
- many things can be understood in terms of fulfilling a causal functional role, e.g. being a table
- the same is true of mental states, e.g. what it is to be a belief, desire, pain, etc
5
Q
computational functionalism
A
- ‘function’ as instruction for computers
- described by a ‘machine table’: a complete list of descriptions of the form ‘if the machine is in state S1 and receives input I1, then it produces output O1, and goes into state S2’
- for every possible input + state combination, an output is assigned, e.g. a drinks dispenser
- mental states are machine table states
- for each possible inputs, they produce a particular output
- (the software is the mind, the hardware is the brain - can’t have the software without the hardware)
6
Q
multiple realisability
A
- any organism that has functional states must have a complex internal organisation
- e.g. if the functional states is defined by what causes it and what it causes, then there must be some inner state that has these causal powers
- if the state is defined by a machine table, there must be distinct states that move between inputs and outputs in the way described
- i.e. inner states are needed to ‘realise’ the functional state
- the nature of inner state doesn’t matter, as long as it realises the function, e.g. different structures of eyes, different chemicals are poisonous
- all of this applies to mental states (as functional states)
- different kinds of creature can have mental states
- it doesn’t matter whether it is physical or mental substance
- mental properties can’t be identical to physical properties, because beings with different physical properties (e.g. different kinds of brain) could nevertheless have the same mental properties, e.g. pain in different species
- what brains are made of is not relevant - it is what they can do that matters
- so, mental properties are ‘multiply realisable’
7
Q
objection: Chinese room
A
- John Searle argued that there is more to consciousness than being able to preform certain functions
- he gives the Chinese room thought experiment:
- ‘imagine a person locked in a room with an instruction book about how to respond to Chinese messages with further Chinese messages. messages are passed in, the person looks them up and send the appropriate message back. from the outside of the room, it appears that the person understands Chinese, but they don’t at all’
8
Q
objection: the possibility of functional duplicate with different qualia (inverted qualia)
A
- qualia: the ‘what it is like’ of certain mental states
- qualia are intrinsic (not relational)
- e.g. the smell of coffee is a certain kind of experience, and it is the same experience whether it caused by coffee or not
- if this is correct, then qualia cannot be functional properties because functional properties are relational, not intrinsic
- according to functionalism, pain is just what causes it and what it causes
- but the qualia of pain seems to be more than that
- it is possible for two people to have inverted qualia, e.g. one sees green grass the way red tomatoes look to the other
- from a functional point of view, the two people are identical, e.g. both call grass green and tomatoes red
- if two people can be functionally identical while having different conscious experiences, the there is more to mental states than their functions
- therefore functionalism is false
9
Q
response to: the possibility of functional duplicate with different qualia (inverted qualia)
A
- Patricia Churchland’s reply: ‘inverted qualia’ isn’t proposed as a empirical hypothesis. empirical hypotheses are tested against evidence. we have no evidence from neuroscience that identical brain function produces distinct conscious experiences. untestable empirical hypotheses are bad science
- the inversion is much too simple - every colour we see has unique similarity relations to other colours (is the inverted red similar to orange)
- counter response: invert the whole spectrum
- reply: the functional roles of colour are too subtle to invert, e.g. humans can make more fine grained distinctions between shades of green, yellow and orange than blue
10
Q
objection: the possibility of a functional duplicate with no mentality/qualia (Ned Block’s China thought experiment)
A
- the population of China replicates the functioning of your mind/brain (as described by a machine table) using radios
- some of these hook up to the nerves of a body
- this is a functional duplicate of a mind, so according to functionalism it should be a mind, it’s hard to see how that mind would have qualia and so it’s hard to see how it could be a mind and therefore, functionalism is false
- is there a Chinese mind - if they replicate my brain when I am in pain, then who is in pain
11
Q
response to: the possibility of a functional duplicate with no mentality/qualia (Ned Block’s China thought experiment)
A
- one response is to claim that the Chinese nation is not functionally identical, e.g. susceptible to different disruptions
- reply: susceptible - but this is irrelevant, e.g. if not disrupted, then functional replication (if those disruptions occurred, then it would indeed no longer be a functional duplicate; however, it’s logically possible that such disruptions wouldn’t occur in which case it is a functional duplicate)
- a physicalist response: mental duplication requires functional and physical duplication, what we are made of matters
12
Q
objection: the knowledge/Mary argument can be applied to functional facts
A
- no amount of facts about function suffices to explain qualia
- the knowledge argument can be applied to functionalism
- Mary knows all the functional facts
- she learns something new when she sees red
- this means that what she learns is something that goes beyond the functional facts
- therefore, there is more to some mental states than functional properties
- therefore, functionalism is fake
13
Q
response to: the knowledge/Mary argument can be applied to functional facts
A
- qualia are simplified representations of complex functional states
- we are not capable of representing these functional states in full detail
- the consequences of this is that Mary would have to be able to deduce the nature of red experiences if she had a complete knowledge of the all the relevant functional facts
