1. Functionalism Computational Role

2. Motivations
A functionalist general purpose input-output device certainly sounds like a computer
Mind does informational things
A machine implementation of functionalism is natural
Computational functions are multiply realisable

3. Turing Machine Turing machines consist of:
an infinite tape divided into squares
a head that reads from and writes to the tape
a finite set of internal states; q0, …, qn
a finite alphabet; b1, …, bm

4. Turing Machine q0 q1 1
1Rq0
#Halt + #
#Lq1
#    #    1   1    1    +    1   1   #   #  q0

5. Turing Machine q0 q1 1
1Rq0
#Halt + #
#Lq1
#    #    1   1    1    +    1   1   #   #  q0

6. Turing Machine q0 q1 1
1Rq0
#Halt + #
#Lq1
#    #    1   1    1    +    1   1   #   #  q0

7. Turing Machine q0 q1 1
1Rq0
#Halt + #
#Lq1
#    #    1   1    1    +    1   1   #   #  q0

8. Turing Machine q0 q1 1
1Rq0
#Halt + #
#Lq1
#    #    1   1    1    1    1   1   #   #  q0

9. Turing Machine q0 q1 1
1Rq0
#Halt + #
#Lq1
#    #    1   1    1    1    1   1   #   #  q0

10. Turing Machine q0 q1 1
1Rq0
#Halt + #
#Lq1
#    #    1   1    1    1    1   1   #   #  q0

11. Turing Machine q0 q1 1
1Rq0
#Halt + #
#Lq1
#    #    1   1    1    1    1   1   #   #  q1

12. Turing Machine q0 q1 1
1Rq0
#Halt + #
#Lq1
#    #    1   1    1    1    1   #   #   # 
Halt

13. Turing Machine q0 q1 1
#Rq1
1Rq1 +
1Halt #
#    #    1   1    1    +    1   1   #   #  q0

14. Machine Functionalism
The computational functionalist claim is that the mind can be thought of as a TM
Mental states of Stephen are to be identified with the internal states of Stephen’s TM

15. Psychology
Instrumentalism
A theory predicts
Realism
A theory explains

16. Difficulties Identity
What does it means for A to have the same mental state as B?
q0 is only definable as the triplet:
{<1, 1Rq0>, <+, 1Rq0>, <#, #Lq1>}
Each state is defined in terms of the other states
Different psychologies can’t even be compared

17. Difficulties Simulation
Do we think that a weather simulation program actually has weather going on inside it?

18. Turing Test
If a machine passes a test that we think could only be passed by a thinking thing then we have no grounds to deny that the machine is thinking.
Have a conversation with A and B, one of them a machine, the other a person. If you can’t tell which is the machine then both are thinking.

19. The Chinese Room
Searle thought that the idea that mental states could be identified with computational states was almost demonstrably incorrect.

20. The Chinese Room Responses System The room + the man + … understands
Reply
Let him memorise it all

21. The Chinese Room Responses Robot Connect the room to the world
Reply
What is the robot really receiving?

22. The Chinese Room Responses Simulator Make the room look like the brain
Reply
Where’s computation now?

23. The Chinese Room
Searle thinks that only  machines can think, ie. brains, but not by computing.