PHLA10 14
The Philosophy of Mind - II
PHLA10 14
Non-Dualist Approaches to Mind
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Three non-dualist theories of mind
– Behaviourism
– Mind/Brain Identity Theory
– Functionalism
They all agree that a materialist viewpoint is the most
promising starting point for investigating the mind
Behaviourism stands out against Identity Theory and
Functionalism because it
– Denies ‘mentalism’
– Mentalism is the idea that mental states are inner
(generally unobservable) states which cause behaviour
and are the effects of physical stimuli
PHLA10 14
Non-Dualist Approaches to Mind
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Logical Behaviourism
– A philosophical theory that asserts that
the meaning of mental state words is the
behaviour that ‘reveals’ them
– Ryle worried about this problem: if
mentalism is true then nobody knows if
anybody else has any mental states (the
‘ghost in the machine’ problem)
– This is called the ‘problem of other minds’
● Traditional answers are weak
– Induction
– Analogy
● Sober prefers abduction
– analogy with many invisible
scientific entities (e.g. electrons)
Gilbert Ryle
(1900-1976)
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Non-Dualist Approaches to Mind
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Logical Behaviourism
– The dispositional analysis of mental state words
– What are dispositions?
● example: solubility
● example: brittleness
– What are dispositional analyses of meaning?
● example: ‘sugar is soluble in water’ means ‘if sugar
is put in water then it dissolves’
● example: ‘glass is brittle’ means ‘if glass is hit then
it shatters’
– What about mental states?
● S believes it is raining = If S goes out, S takes an
umbrella ....
● S wants a beer = If someone asks S if she wants a
beer, S utters ‘yes’
PHLA10 14
Non-Dualist Approaches to Mind
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Logical Behaviourism
– How does logical behaviourism solve the problem of
other minds?
● behaviour is observable
● are dispositions to behave observable?
– Problems for logical behaviourism
1. Circularity problem
– Suppose we define (in part) ‘S believes it is
raining’ as ‘If S goes out, S will take an umbrella’
– Of course, we need many more clauses in the
definition and we need to make it more precise
– But there is a deep problem here: what if S wants
to get wet and believes it is raining?
– All mental state terms seem to have this codependence amongst themselves
PHLA10 14
Non-Dualist Approaches to Mind
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Logical Behaviourism
– Problems for logical behaviourism
2. Irrelevance problem
– The dispositional analysis of mental states does
not refute mentalism
– Compare: the dispositional analysis of brittleness
does not imply that there is no ‘inner state’ of
glass which explains why it has the disposition to
shatter when struck
– Similarly, a dispositional analysis of mental states
would not imply that mental states were not inner
states which explain the creation of behaviour
PHLA10 14
Non-Dualist Approaches to Mind
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Methodological Behaviourism
– Based on the idea that science
should restrict itself to testable
hypotheses
– Testability implies observability
– Behaviour is observable; inner
mental states are not
– Therefore, psychology should
restrict itself to the study of
behaviour
– (Skinner took this idea further,
into a philosophical analysis of
mental states, declaring them
not to exist)
B.F. Skinner (1904-1990)
" . . . yet almost everyone
attributes human behavior to
intentions, purposes, aims and
goals ... as if they had wills,
impulses, feelings, purposes,
and other fragmentary attributes
of an indwelling agent."
PHLA10 14
Non-Dualist Approaches to Mind
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Methodological Behaviourism’s ‘Negative Claim’
– The motivation of methodological behaviourism is too
strong
– It would deny science the ability to hypothesize
unobservable entities
● But almost all sciences do this (e.g. electrons, gene)
– Framework hypotheses vs. particular hypotheses within
a framework
● Atomic theory is a framework
● It cannot be refuted in a single experiment
● Particular atomic hypotheses can be tested (e.g.
atoms have component parts)
● Similarly, mentalism is a framework of explanation
of behaviour
● Particular ascriptions of belief/desire can be tested
PHLA10 14
Non-Dualist Approaches to Mind
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Methodological Behaviourism’s ‘Positive Claim’
– All behaviour is explicable in purely behavioural terms,
without resort to any ‘inner states’ (mentalism)
– The ‘conditioning model’ of meth. behaviourism
Problems with the positive claim
– Conditioning does not explain ‘novel behaviours’
● Sober’s ‘facing the robber’ example
● It is easy to think of other examples
– Environmental determinism is false
● Genetics and behaviour
– Spider webs: no conditioning history
PHLA10 14
Non-Dualist Approaches to Mind
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Mind/Brain Identity Theory (IT)
– IT is an a posteriori theory
● No a priori, purely philosophical arguments for it
– (unlike dualism and behaviourism)
– IT asserts that science has (or will) show that the best
explanation of the nature of the mind is that mind is
identical to (a working) brain
– Our understanding of mind will follow a path similar to
many other previous mysteries
● lightning
● chemicals and atomic theory
● life and chemistry
– contrast modern account with vitalism
– compare vitalism/life with dualism/mind
PHLA10 14
Non-Dualist Approaches to Mind
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Vitalism and the mystery of life
– There once seemed a huge gap between simple ‘dead’
matter and living beings
● Nehemiah Grew (1701): And although we add the
Auditory nerves to the Ear, the Brain to the
Nerves ... yet is it still but adding Body to Body ...
which, howsoever Curious, and Many; can never
bring Life out of themselves, nor make one another
to be Vital
– Hans Driesch and the magic machine
● Sea urchin experiments revealed that any part of
the sea urchin embryo could develop into a whole
and proper sea urchin (how could a mechanical,
purely material system have such a property)
– The DNA revolution provides framework of answer to
vitalism
PHLA10 14
Non-Dualist Approaches to Mind
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Mind/Brain Identity Theory (IT)
– Correlation versus Identity
● Science can reveal the neural correlates of mental
states (i.e. the brain states that occur in
synchronization with mental states)
● It is a further step to go from correlation to identity
– The Principle of Parsimony (simplicity)
● Given two hypotheses, H1 and H2
● That are explanatorily equal,
● Chose the simpler one
● IT is simpler than dualism ...
– Is Parsimony a guide to Truth?
● Why would it be?
● Prudence vs. evidence again
● What if it isn’t?
PHLA10 14
Non-Dualist Approaches to Mind
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Mind/Brain Identity Theory (IT)
– Other advantages of IT
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Solves the mind-body causation problem
Explains the correlation of mental states with brain states
Integrates better with the rest of our scientific knowledge
Problems?
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The Problem of Alien Minds
● Intelligent aliens seem possible
● They might not have brains!
● Intelligent computers may be possible
● They don’t have brains
The Problem of Consciousness
● Knowing ‘what it is like’ to see red seems to be
independent of knowledge of the brain
– A blind person could know everything about the brain
without knowing what it was like to experience colours
PHLA10 14
Non-Dualist Approaches to Mind
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Functionalism
– The type/token distinction
● How many ‘e’s in the last line?
● Those are tokens of a letter-type
– IT identifies
● mental tokens with brain tokens
● mental types with brain types
– Functionalism only identifies
● mental tokens with brain tokens
Charles Peirce
● denies mental types match brain types
(1839-1914)
– Multiple Realizability
● Functional types: types of things whose identity depends
on a functional description (what they can do)
– can be built or realized in many different ways from
many different materials
– examples: light bulb, mousetrap, chair, watch
PHLA10 14
Non-Dualist Approaches to Mind
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Functionalism
– Functionalism asserts that mental states are functional
kinds, defined in terms of their relations to behaviour,
perception and each other
– There could be many very different ways to realize
such mental states
– Maybe we could build a computer that could think and
feel (but it would not have a brain)
– Animals like insects and birds have brains quite
different form ours but (might) think and feel
– Maybe there are aliens somewhere that think and feel
(but do not have brains at all like ours)
– Functionalism is a materialist theory insofar as it claims
that all realizations of mental state types are material
PHLA10 14
Non-Dualist Approaches to Mind
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Functionalism
– Functionalism’s analysis of mental states is similar to
logical behaviourism’s
– EXCEPT functionalism allows other mental states in its
dispositional definitions
– So, instead of the behaviourist:
● S believes it is raining = if S goes out then S takes
an umbrella
– The functionalist says:
● S believes it is raining = if S goes out and S wants to
stay dry then S takes an umbrella
– Note the ‘holism’ of mental state analysis: mental
states come as a ‘package deal’; consider wanting:
● S wants to stay dry = If S goes out and S believes it
is raining then S takes an umbrella
PHLA10 14
Non-Dualist Approaches to Mind
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Functionalism
– Turing and the Computer Analogy
– Computer programs are functional types
– They need hardware to be realized in the
world, but the software is not a ‘different’
kind of hardware – it is a functional
specification of a certain set of tasks
– We arrive at the computer analogy
● As software is to hardware, so mind is to
matter
● So, our brains are the hardware on which
the program we call mind is running
● (Does this mean we could ‘upload’ our
mind program to a different kind of
hardware??)
Alan Turing
(1912-54)
PHLA10 14
Non-Dualist Approaches to Mind
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Functionalism
– The previous examples of functional analysis are of
course very crude and preliminary
– For example, we might improve them by changing ‘S
takes an umbrella’ to ‘S tries to take an umbrella’ (why
is this an improvement?)
– The problem of consciousness
● Functionalism may not handle sensory qualities
● Why do some states feel just the way they do?
● Inverted spectrum argument
– Why couldn’t some of us see colour ‘backwards’
(an inverted perceiver sees what we would call
green when looking at a ripe tomato; sees what we
would call red when looking at grass ...)
● Why is this a problem for functionalism?