Mind-Brain Type Identity Theory Quick Recap Which of the theories we’ve discussed so far do you find most convincing? Why? Substance Dualism Logical Behaviourism Property Dualism Mind-Brain Type Identity Theory

What do these items have in common? What makes them tin-openers? What does this picture show? What makes them legs?

Defined by function There are things we encounter everyday that, rather than being defined by the way they are made, the way they look or the material they are made out of, are instead defined by the function they perform or their causal role. Taking an example from the last page, it doesn’t matter whether the tin-opener is simply a sharp piece of metal or a complicated electric version, it’s still considered a tin-opener because functionally it opens cans. The item is therefore defined by it’s function / causal role in opening cans.

Input / Output X having a function or a causal role means that we can input certain things and X will output something accordingly. These inputs / outputs may be simple information or complex physical things. Input Output

What inputs / outputs do eyes have? Defined by function This idea of a causal role or function is not just true of material goods either – our bodies are made up of parts that we define by function rather than design. This allows us to identify animal “parts” using the same terms we use for our own bodies, despite the fact that they may be very different design wise. What inputs / outputs do eyes have?

Any idea how this might apply to our discussion of mind? Which of these are best defined functionally? Which are best defined in some other way (e.g. their design or what they’re made of)? A wheel Money The moon An ear A screwdriver Salt A mobile phone The prime minister A rabbit A heart Any idea how this might apply to our discussion of mind?

Mental States as functions… Functionalists argue that mental states are best understood as functional entities like hearts, or tin- openers rather than what they’re made of. Their essential or defining feature is the causal role they play in relation to their inputs / outputs. What inputs / outputs do our mental states have?

Mental States as functions… Functionalists argue that mental states are best understood as functional entities like hearts, or tin- openers. Their essential or defining feature is the causal role they play in relation to their inputs / outputs. Environmental effects on the body Other mental states Other mental states Bodily behaviour Input Output

Functionalism Key Thinker: Hilary Putnam (1926-2016) Where: Psychological Predicates 1967 Who: Important 20th Century philosopher in multiple fields. Known as someone who applied philosophical investigation rigorously and as such often changed his own opinions as he discovered flaws.

Functionalism Example So, to be a particular sort of mental state is to have a particular sort of functional role. For example: A pain in the foot will be defined in terms of the role that it plays in dealing with sensory inputs and sensory / behavioural outputs. Triggers mental state to avoid source of pain Produced by damage to the body Functional definition of pain Triggers pain behaviour to shout out loud Input Output

Functionalism Example What would be the functional definition of the belief that it is raining outside? Functional definition of the belief it’s raining outside Input Output

But what is the mind? This question is irrelevant. Like we saw earlier with the tin opener, the exact material makeup or organisation of the thing doesn’t matter, as long as it performs the functional role of a tin-opener. What matters is what the thing does, not what it is made out of. This means that functionalism as a theory is technically compatible with both dualism and physicalism. Mental states could be non-physical and spiritual or they could be physical and linked to the brain, it doesn’t matter as long as they perform mind functions.

But what is the mind? That being said functionalism is generally accepted as a physicalist theory. Most supporters arguing that it is overwhelmingly likely that any thing performing the functional role of the mental will be physical. This means they believe that the mix of chemicals and neurons in our brains performs the functional role of the mental for humans. But remember the precise material that makes up the brain is not REALLY important, I could have a completely artificial brain and as long as it still performs the function of “the mental” then we can still say I have a mind. Similarly yours could be missing certain parts but as long as it still performs the function of the mental you still have a mind.

Tasks List three things that are defined by their functions rather than their physical make up. Explain why for each. Explain how these examples relate to our minds, illustrate by outlining the functional role of a particular mental state. (Remember inputs / outputs) Explain why Putnam and other functionalists believe that it doesn’t matter what material the mind is made out of. Summarise functionalism in 5 key points on your whiteboard for me to check. Extension: How is functionalism different to mind-brain identity theory or behaviourism?

What was the problem for MBTIT illustrated by the pictures above What was the problem for MBTIT illustrated by the pictures above? Why does functionalism take a different approach here?

Differences with MBTIT The crucial difference between functionalism and MBTIT is that functionalists argue that the material / organisation of the physical thing doesn’t matter, only it’s functional role as a mind. Thus the alien, dog and man-with-half-a-brain all have minds as long their “brains” can perform the same functions as our “brains”. MBTIT’s on the other hand argue that only things made up of the same basic stuff as us, organised in the same way can have a mind. This leads to the issue of multiple realisability functionalism neatly avoids.

Functionalism Example What is the difference between the functional example below and the definition of mental states according to behaviourism? Triggers mental state to avoid source of pain Produced by damage to the body Functional definition of pain Triggers pain behaviour to shout out loud Input Output

Differences with Behaviourism Behaviourists generally argue that each mental state can be defined in terms of it’s behavioural output – that is to say mental states should be described in terms of how we behave. Functionalists believe this is too simple, instead arguing that we should also consider that our mental states can cause behaviour and other mental states. This means that functionalism takes into account what is going on internally and fits much better with our common understanding of “mind”.

Final point: Analogies What does this complex system of inputs and outputs remind you of? Triggers mental state to avoid source of pain Produced by damage to the body Functional definition of pain Triggers pain behaviour to shout out loud Input Output

Machine State Functionalism The theory is sometimes known as machine state functionalism due to the similarities that can be drawn between this view of the mental and the way that simple or complex machines work. Thus we may say the physical makeup of our brain is similar to the hardware of a computer (inputting certain information and states) whilst the mental is the software logging those inputs. The software / our mind is then responsible for organising and processing before feeding out information in a different form (outputs) i.e. through the monitor, or as behaviour, or as other mental states.

Does this mean machines have minds? Well no, not yet. Our minds are extremely complex, they have a huge amount of possible inputs and outputs. Machines can’t currently match this. However if, in the future we could run a sophisticated enough computer program on sufficiently powerful hardware there is nothing to say that the resulting machine would not have a mind. It is simply a matter of degree, rather than material.

Do you think it is possible machines will ever have minds? Final Summary: Do you think it is possible machines will ever have minds?

Is functionalism an effective theory of mind? Final Summary: Is functionalism an effective theory of mind?