Agenda Pomona College ֠ Functionalism LCS 11: Cognitive Science ֠ Turing, 1950 Functionalism ֠ Group discussions of objections ֠ GQ 2.2 due Tue, 9PM ֠ Reading Jesse A. Harris • Cunningham, 2000, pp. 54-69 • Ramachandran, 2005, pp. 83-89 February 18, 2013 Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 1 Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 2 Functionalism Multiple realizability Functionalist slogan In a nutshell What matters is the software, not the hardware; cognitive Define the mind not in terms of its composition, but rather its systems can be realized in muliple ways and are equivalent so function – what can it do? long as they perform the same functions. Exercise: functionalist definitions Take any object and write out a functionalist definition for it. Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 3 Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 4
Multiple realizability Multiple realizability – the eye 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 Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 6 Functionalism – some history Functionalism – some history ◮ Babbage’s Analytical Engine ◮ Coincided with the stellar rise of computation and built from gears and cylinders, computing machines in the 50s and 60s occupied the space of a train car ◮ Computing machines in the 50s ◮ Machines are constructed in different manners, yet may and early 60s; vacuum tubes perform essentially the same abstract computation ◮ Transistors in slivers of silicon, and more advances being made Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 7 Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 8
Turing machines Turing machines Turing machines Computers At Turing’s time, computers typically referred to people who 1. Abstract – Concepts, not implementation, important computed, not machines. 2. Universal – All digital computers are equivalent in a sense 3. Discrete – Consist of discrete states Computing machines Effective computability 1. Store – Store of information (paper/memory) Can compute a task if you can specify a set of procedures 2. Executive unit – Carries out operation in computation carried out by the machine to complete the task. The Turing 3. Control – Checks that the computation follows table of machine provides a set of devices which are equivalent in instructions. terms of their computational power. Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 9 Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 10 Turing machines Turing test Structure 1. Tape (infinite) with cells to be filled by predetermined symbols (0,1) 2. Scanner to read/write symbols in cells on tape The question Can machines think? to 3. Program ; finite list of instructions (algorithm) be replaced with a less ambiguous formulation: Could some conceivable digital computer perform well in the imitation game. http://www.youtube.com/watch?v=AgW6HplOZV0 Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 11 Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 12
Imitation game Behavior ◮ All that matters is that the A a digital computer machine emulates the B a human participant appropriate behavior of a C a judge human. ◮ The actual sorts of processes C communicates with A and B via might well differ. teleprinter or similar device Turing’s 1950 prediction “The machine ... would not attempt to give the right answers to the In 50 years time, there will be digital arithmetic problems. It would computers who will pass the deliberately introduce mistakes in a imitation game 30% of the time after manner calculated to confuse the 5 minutes of questioning, p. 442 interrogator.” p.448 Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 13 Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 14 7 objections Learning Each group will consider Turing’s responses to one objection: Shaping of mind Objection 2: The ‘Heads in the Sand’ Objection (page 444) 1. Initial state of mind Objection 3: The Mathematical Objection (page 444) 2. Education Objection 4: The Argument from Consciousness (page 445) 3. Other experience Objection 5: Argument from Various Disabilities (page 447) Mind as blank sheet Objection 6: Lady Lovelace’s Objection (page 450) “Presumably the child-brain is something like a notebook as one buys it from the stationers. Rather little mechanism, and Objection 7: Continuity in the Nervous System (page 451) lots of blank sheets.” What viewpoint does this remind you of? Objection 8: Argument from Informality of Behavior (page 452) Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 15 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 http://www.manifestation.com/neurotoys/eliza.php3 Joseph Weizenbaum (1923–2008) Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 17 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 Brief question Loebner prize Turing’s prediction did not come true. Do you think it will come true ◮ In 1990, Hugh Loebner offered in the next 50 years, or at all? Why? $100,000 to the first group who could create a computer Brief question 2 capable of passing the Turin Is it possible for machines to possess test intelligence? Is the Turing test an ◮ Each year, $2,000 awarded to appropriate method of assessing the the most human-computer general question of intelligence? ◮ 2013 contest to be held on http://xkcd.com/329/ September 14th in Ireland Jesse A. Harris: LCS 11: Cognitive Science, Functionalism 21 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
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