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Intelligence Artificial Intelligence Ian Gent The Turing Test.

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1 Intelligence Artificial Intelligence Ian Gent The Turing Test

2 Intelligence Artificial Intelligence Part I :Turing’s Imitation Game Part II: Some sample games from the 60’s to the 90’s The Turing Test

3 3 Alan M Turing, Hero zHelped to found theoretical CS y1936, before digital computers existed zHelped to found practical CS ywartime work decoding Enigma machines yACE Report, 1946 zHelped to found practical AI yfirst (simulated) chess program zHelped to found theoretical AI …

4 4 Can Machines Think? zComputing Machinery and Intelligence yAlan M Turing yMind, Vol LIX, Number 236 (1950) yCan be found reprinted in many places ye.g. Computers and Thought

5 5 Can Machines Think? zTuring starts by defining machine & think yWill not use everyday meaning of the words xotherwise we could answer by Gallup poll yInstead, use a different question xclosely related, but unambiguous z“I believe the original question to be too meaningless to deserve discussion”

6 6 The Imitation Game zInterrogator in one room ydigital computer in another room yperson in a third room zFrom typed responses only, can interrogator distinguish between person and computer? zIf the interrogator often guesses wrong, say the machine is intelligent. zUsually done with one machine/person at a time

7 7 A sample imitation game zTuring suggests some specimen Q & A’s: zQ: Please write me a sonnet on the subject of the Forth Bridge zA: Count me out on this one, I never could write poetry zQ: Add to y(pause about 30 seconds) zA: zQ: Do you play chess? zA: Yes zQ: I have K at my K1, and no other pieces. You have only K at K6 and R at R1. It is your move. What do you play? y(pause about 15s) zA: R-R8 mate

8 8 What did Turing think? zTuring (in 1950) believed that by 2000 ycomputers available with 128Mbytes storage yprogrammed so well that interrogators have only a 70% chance after 5 minutes of being right z“By 2000 the use of words and general educated opinion will have altered so much that one will be able to speak of machines thinking without expecting to be contradicted”

9 9 Objections and Responses zTuring discusses responds to some objections ySome of them can be dealt with quite quickly zThe Theological Objection yMan has a soul, machines do not yAT: Can we deny His power to give a soul to a machine zHeads in the sand yI don’t like the idea so I will ignore it zArgument from various disabilities yNo machine can X (e.g. tell right from wrong) yAT: Becomes a less powerful argument each day

10 10 Some more objections zLady Lovelace’s [Ada’s] objection ycomputers do whatever we know how to order them to perform, so computers cannot do anything really new yAT: Machines constantly surprise us. zArgument from informality of behaviour yimpossible to write down formal rules for every situation yAT: Scientifically impossible to prove people not driven by rules zArgument from ESP yTelepathy would let humans win imitation game yAT: Put competitors in ‘telepathy-proof’ room (!)

11 11 Three more serious objections zArgument from Consciousness y“No mechanism could feel pleasure, grief … yAT: Danger of Solipsism yAT: Imitation game exists now - in oral exams yProbably the most contentious objection zArgument from continuity in the nervous system ythe brain does not operate digitally yAT: computers can simulate continuous behavior, eg. Statistically

12 12 Three more serious objections zMathematical Objection yGodel’s theorem, Halting problem, etc, show that machines cannot do ‘meta-reasoning’. yAT: We too often give wrong answers ourselves to be justified in being very pleased at fallibility of machines zThe mathematical, consciousness, and continuity arguments deserve further discussion, … y… but that’s another story

13 13 Some Famous Imitation Games z1960sELIZA yRogerian psychotherapist z1970sSHRDLU yBlocks world reasoner z1980s NICOLAI yunrestricted discourse z1990sLoebner prize ywin $100,000 if you pass the test

14 14 The problem with ELIZA zEliza used simple pattern matching myme y“Well, my boyfriend made me come here” y“Youryou y“Your boyfriend made you come here?” zEliza written by Joseph Weizenbaum zWeizenbaum so upset at credibility of users… yhis secretary wanted to use it only in private ypsychotherapists excited at prospect of Eliza-booths z… he wrote a book to debunk the possibilities y“Computer Power and Human Reason”

15 15 The problem with SHRDLU zSHRDLU had a very limited domain z“Look-ma-no-hands” AI yhard to abstract lessons learnt ynatural language processing intermingled with planning, etc zSHRDLU written by Terry Winograd ywith this and later work, he made major contributions to AI xespecially in natural language processing

16 16 The problem with NICOLAI zNICOLAI was not a computer program! zDoug Hofstadter conducted dialogue, believing NICOLAI was electronic z(Almost) passed the Reverse Turing Test zTricks like the occasional dumb answer ybut “too much cleverness in these weird responses”

17 17 The problem with the Loebner Prize zJason Hutchens programmed the 1996 winner zThen wrote an article y“How to pass the Turing test by cheating” ! y“Turing’s imitation game in general is inadequate as a test of intelligence, as it relies solely on the ability to fool people, and this can be very easy to achieve, as Weizenbaum found.”

18 18 Summary: The Turing Test zThe Turing test turns a philosophical question... xCan Machines think? z… Into an operational one xCan machines play the imitation game? zWe are not near writing programs to pass the test zThe Turing test does NOT drive much AI research zImproving the capabilities of computers DOES


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