lcs 11: cognitive science - functionalism

Pomona College

LCS 11: Cognitive ScienceFunctionalism

Jesse A. Harris

February 18, 2013

Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 1

Agenda

Functionalism

Turing, 1950

Group discussions of objections

GQ 2.2 due Tue, 9PM Reading

• Cunningham, 2000, pp. 54-69• Ramachandran, 2005, pp. 83-89


Functionalism

In a nutshellDeVne the mind not in terms of its composition, but rather itsfunction – what can it do?

Exercise: functionalist deVnitionsTake any object and write out a functionalist deVnition for it.


Multiple realizability

Functionalist sloganWhat matters is the software, not the hardware; cognitivesystems can be realized in muliple ways and are equivalent solong as they perform the same functions.


Multiple realizability

Brief questionHow does the idea of multiple realizations contrast withphysicalism? What facts can multiple realizations capture thatsome types of physicalism could not?

Brief question 2Are functionalism and physicalism incompatible?


Multiple realizability – the eye


Functionalism – some history

I Coincided with the stellar rise of computation andcomputing machines in the 50s and 60s

I Machines are constructed in diUerent manners, yet mayperform essentially the same abstract computation


Functionalism – some history

I Babbage’s Analytical Enginebuilt from gears and cylinders,occupied the space of a train car

I Computing machines in the 50sand early 60s; vacuum tubes

I Transistors in slivers of silicon,and more advances being made


Turing machines

ComputersAt Turing’s time, computers typically referred to people whocomputed, not machines.

Computing machines

1. Store – Store of information (paper/memory)

2. Executive unit – Carries out operation in computation

3. Control – Checks that the computation follows table ofinstructions.


Turing machines

Turing machines

1. Abstract – Concepts, not implementation, important

2. Universal – All digital computers are equivalent in a sense

3. Discrete – Consist of discrete states

EUective computabilityCan compute a task if you can specify a set of procedurescarried out by the machine to complete the task. The Turingmachine provides a set of devices which are equivalent interms of their computational power.


Turing machinesStructure1. Tape (inVnite) with cells to be Vlled by predetermined

symbols (0,1)

2. Scanner to read/write symbols in cells on tape

3. Program; Vnite list of instructions (algorithm)

http://www.youtube.com/watch?v=AgW6HplOZV0


Turing test

The question Can machines think? tobe replaced with a less ambiguousformulation: Could some conceivabledigital computer perform well in theimitation game.


http://www.youtube.com/watch?v=AgW6HplOZV0

Imitation game

A a digital computer

B a human participant

C a judge

C communicates with A and B viateleprinter or similar device

Turing’s 1950 predictionIn 50 years time, there will be digitalcomputers who will pass theimitation game 30% of the time after5 minutes of questioning, p. 442


Behavior

I All that matters is that themachine emulates theappropriate behavior of ahuman.

I The actual sorts of processesmight well diUer.

“The machine ... would not attemptto give the right answers to thearithmetic problems. It woulddeliberately introduce mistakes in amanner calculated to confuse theinterrogator.” p.448


7 objectionsEach group will consider Turing’s responses to one objection:

Objection 2: The ‘Heads in the Sand’ Objection (page 444)

Objection 3: The Mathematical Objection (page 444)

Objection 4: The Argument from Consciousness (page 445)

Objection 5: Argument from Various Disabilities (page 447)

Objection 6: Lady Lovelace’s Objection (page 450)

Objection 7: Continuity in the Nervous System (page 451)

Objection 8: Argument from Informality of Behavior (page 452)


Learning

Shaping of mind

1. Initial state of mind

2. Education

3. Other experience

Mind as blank sheet“Presumably the child-brain is something like a notebook asone buys it from the stationers. Rather little mechanism, andlots of blank sheets.” What viewpoint does this remind you of?


Chatbots

ELIZAI Modeled after non-directive

Rogerian therapyI Inverts words with keywords, as

a kind of language gameI Remarkably eUective

Joseph Weizenbaum(1923–2008)


http://www.manifestation.com/neurotoys/eliza.php3

Chatbots

CleverbotI Started out with very little

knowledgeI Taught 5 million lines of

conversation in 10 yearsI 200,000 request per hourI 3 million conversations a month

http://cleverbot.com/

Rollo Carpenter(b. 1965)


http://www.manifestation.com/neurotoys/eliza.php3

http://cleverbot.com/

Turing test in action

Loebner prize

I In 1990, Hugh Loebner oUered$100,000 to the Vrst group whocould create a computercapable of passing the Turintest

I Each year, $2,000 awarded tothe most human-computer

I 2013 contest to be held onSeptember 14th in Ireland


Brief questionTuring’s prediction did not cometrue. Do you think it will come truein the next 50 years, or at all? Why?

Brief question 2Is it possible for machines to possessintelligence? Is the Turing test anappropriate method of assessing thegeneral question of intelligence?

http://xkcd.com/329/

GQ 2.2, due Tue by 9PM

Do you think that consciousness constitutes one phenomenon ormany phenomena, in Cunningham’s sense (pp. 64-69)? Rather thansimply stating your opinion, take a concrete example from any of thereading from this class so far and use that example in yourargument. You can even chose an example that goes against yourintuition!

Group leaders: Stephen, Daniel, Adele, Sam, Sarah, Nico, Noah, Alex,Ryan


http://xkcd.com/329/

lcs 11: cognitive science - functionalism

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