LCS 11: Cognitive Science Turing, 1950 Functionalism Group - - PowerPoint PPT Presentation

Pomona College

LCS 11: Cognitive Science

Functionalism

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

Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 2

Functionalism

In a nutshell

Define the mind not in terms of its composition, but rather its function – what can it do?

Exercise: functionalist definitions

Take any object and write out a functionalist definition for it.

Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 3

Multiple realizability

Functionalist slogan

What matters is the software, not the hardware; cognitive systems can be realized in muliple ways and are equivalent so long as they perform the same functions.

Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 4

Multiple realizability

Brief question

How does the idea of multiple realizations contrast with physicalism? What facts can multiple realizations capture that some types of physicalism could not?

Brief question 2

Are functionalism and physicalism incompatible?

Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 5

Multiple realizability – the eye

Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 6

Functionalism – some history

◮ Coincided with the stellar rise of computation and

computing machines in the 50s and 60s

◮ Machines are constructed in different manners, yet may

perform essentially the same abstract computation

Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 7

Functionalism – some history

◮ Babbage’s Analytical Engine

built from gears and cylinders,

• ccupied the space of a train car

◮ Computing machines in the 50s

and early 60s; vacuum tubes

◮ Transistors in slivers of silicon,

and more advances being made

Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 8

Turing machines

Computers

At Turing’s time, computers typically referred to people who computed, 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 of

instructions.

Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 9

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

Effective computability

Can compute a task if you can specify a set of procedures carried out by the machine to complete the task. The Turing machine provides a set of devices which are equivalent in terms of their computational power.

Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 10

Turing machines

Structure

• 1. Tape (infinite) with cells to be filled by predetermined

symbols (0,1)

• 2. Scanner to read/write symbols in cells on tape
• 3. Program; finite list of instructions (algorithm)

http://www.youtube.com/watch?v=AgW6HplOZV0 Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 11

Turing test

The question Can machines think? to be replaced with a less ambiguous formulation: Could some conceivable digital computer perform well in the imitation game.

Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 12

Imitation game

A a digital computer B a human participant C a judge C communicates with A and B via teleprinter or similar device

Turing’s 1950 prediction

In 50 years time, there will be digital computers who will pass the imitation game 30% of the time after 5 minutes of questioning, p. 442

Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 13

Behavior

◮ All that matters is that the

machine emulates the appropriate behavior of a human.

◮ The actual sorts of processes

might well differ. “The machine ... would not attempt to give the right answers to the arithmetic problems. It would deliberately introduce mistakes in a manner calculated to confuse the interrogator.” p.448

Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 14

7 objections

Each 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)

Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 15

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 as

• ne buys it from the stationers. Rather little mechanism, and

lots of blank sheets.” What viewpoint does this remind you of?

Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 16

Chatbots

ELIZA

◮ Modeled after non-directive

Rogerian therapy

◮ Inverts words with keywords, as

a kind of language game

◮ Remarkably effective

Joseph Weizenbaum (1923–2008)

Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 17

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

Chatbots

Cleverbot

◮ Started out with very little

knowledge

◮ Taught 5 million lines of

conversation in 10 years

◮ 200,000 request per hour ◮ 3 million conversations a month

http://cleverbot.com/

Rollo Carpenter (b. 1965)

Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 19

Turing test in action

Loebner prize

◮ In 1990, Hugh Loebner offered

$100,000 to the first group who could create a computer capable of passing the Turin test

◮ Each year, $2,000 awarded to

the most human-computer

◮ 2013 contest to be held on

September 14th in Ireland

Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 21

Brief question

Turing’s prediction did not come

• true. Do you think it will come true

in the next 50 years, or at all? Why?

Brief question 2

Is it possible for machines to possess intelligence? Is the Turing test an appropriate method of assessing the general question of intelligence?

http://xkcd.com/329/

GQ 2.2, due Tue by 9PM

Do you think that consciousness constitutes one phenomenon or many phenomena, in Cunningham’s sense (pp. 64-69)? Rather than simply stating your opinion, take a concrete example from any of the reading from this class so far and use that example in your

• argument. You can even chose an example that goes against your

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

Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 23