[lit-ideas] Re: Turing, Grice, Wittgenstein - Functionalism

  • From: Jlsperanza@xxxxxxx
  • To: lit-ideas@xxxxxxxxxxxxx
  • Date: Fri, 13 Jan 2012 07:57:40 -0500 (EST)


In a message dated 1/13/2012 6:33:26 A.M. UTC-02, donalmcevoyuk@xxxxxxxxxxx 
 writes:

Some sort of 'functionalism' is what I took to underpin  Turing's 
'Imaginary Game', though his is a tendentious rather than explicit  way of 
proposing 
a functionalist approach. (Perhaps we should turn to  'functionalism' as a 
topic, pro and con. As Grice defends it, JLS would have a  stake in the game.)
 
This below may help.
Cheers,
Speranza
 
begin quoted text:
 
_http://en.wikipedia.org/wiki/Functionalism_(philosophy_of_mind_ 
(http://en.wikipedia.org/wiki/Functionalism_(philosophy_of_mind) )
 
Types of  functionalism  
[_edit_ 
(http://en.wikipedia.org/w/index.php?title=Functionalism_(philosophy_of_mind)&action=edit&section=3)
 ]  Machine-state  functionalism
 
 (http://en.wikipedia.org/wiki/File:Maquina.png)  
 
 (http://en.wikipedia.org/wiki/File:Maquina.png) 
Artistic representation of a _Turing  machine_ 
(http://en.wikipedia.org/wiki/Turing_machine) .


The broad position of "functionalism" can be articulated in many different  
varieties. The first formulation of a functionalist theory of mind was put 
forth  by _Hilary Putnam_ (http://en.wikipedia.org/wiki/Hilary_Putnam) 
._[5]_ 
(http://en.wikipedia.org/wiki/Functionalism_(philosophy_of_mind)#cite_note-Putnam1960-4)
 _[6]_ 
(http://en.wikipedia.org/wiki/Functionalism_(philosophy_of_mind)#cite_note-Putnam1967-5)
   This formulation, which is now called 
machine-state functionalism, or  just machine functionalism, was inspired by 
the analogies which Putnam  and others noted between the _mind_ 
(http://en.wikipedia.org/wiki/Mind)  and the theoretical "machines"  or 
computers capable 
of computing any given _algorithm_ (http://en.wikipedia.org/wiki/Algorithm) 
 which were developed  by _Alan  Turing_ 
(http://en.wikipedia.org/wiki/Alan_Turing)  (called _Universal Turing  
machines_ 
(http://en.wikipedia.org/wiki/Universal_Turing_machine) ). 
In non-technical terms, a Turing machine can be visualized as an 
indefinitely  and infinitely long tape divided into rectangles (the memory) 
with a 
box-shaped  scanning device that sits over and scans one component of the 
memory at a time.  Each unit is either blank (B) or has a 1 written on it. 
These 
are  the inputs to the machine. The possible outputs are: 
    *   Halt: Do nothing. 
    *   R: move one square to the right. 
    *   L: move one square to the left. 
    *   B: erase whatever is on the square. 
    *   1: erase whatever is on the square and print a '1.
An extremely simple example of a Turing machine which writes out the 
sequence  '111' after scanning three blank squares and then stops is specified 
by 
the  following machine table:     State One State Two State Three  B write 
1; stay in state 1 write 1; stay in state 2 write 1; stay in state 3  1 go 
right; go to state 2 go right; go to state 3 [halt] 
This table states that if the machine is in state one and scans a blank  
square (B), it will print a 1 and remain in state one. If it is in  state one 
and reads a 1, it will move one square to the right and also go  into state 
two. If it is in state two and reads a B, it will print a  1 and stay in 
state two. If it is in state two and reads a 1, it  will move one square to the 
right and go into state three. If it is in state  three and reads a B, it 
prints a 1 and remains in state three.  Finally, if it is in state three and 
reads a 1, then it will stay in  state three. 
The essential point to consider here is the nature of the states of  the 
Turing machine. Each state can be defined exclusively in terms of its  
relations to the other states as well as inputs and outputs. State one, for  
example, is simply the state in which the machine, if it reads a B,  writes a 1 
and stays in that state, and in which, if it reads a 1,  it moves one square 
to the right and goes into a different state. This is the  functional 
definition of state one; it is its causal role in the overall system.  The 
details 
of how it accomplishes what it accomplishes and of its material  
constitution are completely irrelevant. 
According to machine-state functionalism, the nature of a mental state is  
just like the nature of the automaton states described above. Just as state  
one simply is the state in which, given an input B, such and such  happens, 
so being in pain is the state which disposes one to cry "ouch", become  
distracted, wonder what the cause is, and so forth. 
-- end quoted text. 

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