1. josh.ppt version:20091008

2. Artificial Intelligence, Natural Language, and the Chinese Room William J. Rapaport Department of Computer Science & Engineering, Department of Philosophy, Department of Linguistics, and Center for Cognitive Science rapaport@buffalo.edu http://www.cse.buffalo.edu/~rapaport

3. What Is AI? 1.“The science of making machines do things that would require intelligence if done by humans.” –Marvin Minsky –Using humans to tell us how to program computers e.g., play chess, solve calculus problems, … e.g., see, use language, … –“classical AI”

4. What Is AI? (continued) 2.“The use of computer programs and programming techniques to cast light on the principles of intelligence in general and human thought in particular.” –Margaret Boden –Using computers to tell us something about humans. –Cognitive science

5. What Is AI? (cont’d) Can computers think? Is thinking computable? –E.g., is natural-language understanding computable? –In general: Is “cognition” computable? If so: –how can we program computers to do it? –how will we know when we’ve succeeded? one possible answer: The Turing Test

6. Alan Turing British, 1912-1954 “invented” the idea of computation –Turing “machine” cracked the Nazi “Enigma” code during WW II devised test for AI: –Turing “test”

7. Turing Machine Everything that is computable can be computed using: –a machine with: an infinite tape divided into squares (with ‘0’ on each) a movable read-write head –a programming language with only: 2 nouns: 0, 1 2 verbs: move(left or right), print(0 or 1) 3 grammar rules: –sequence (begin do this; then do that end) »where “this”/“that” = print, move, or any grammatical instruction –selection (if current square=0 then do this else do that) –repetition (while current square=0 [or: current square=1] do this) Not everything can be computed! –“halting problem”: can’t always detect infinite loops –can cognition be computed?

8. How Computers Can Think If (human) cognition is computable, then (human) cognitive states & processes can be expressed as algorithms If cognitive states & process can be expressed as algorithms, then they can be implemented on non-human computers

9. How Computers Can Think (cont’d) Are computers executing such cognitive algorithms merely simulating cognitive states & processes? Or are they actually exhibiting them? –Do such computers think? Answer: Turing’s Test Objection: Searle’s Chinese-Room Argument My reply: Computers can understand just by manipulating symbols (like a Turing machine)

10. The Imitation Game MAN “I’m the woman” WOMAN “I’m the woman” INTERROGATOR

11. The Turing Test The Imitation Game MAN “I’m the woman” WOMAN “I’m the woman” INTERROGATOR COMPUTER

12. The Turing Test #2 The Imitation Game MAN “I’m the woman” WOMAN “I’m the woman” INTERROGATOR COMPUTERMAN man

13. The Turing Test #3 The Imitation Game MAN “I’m the woman” WOMAN “I’m the woman” INTERROGATOR COMPUTERHUMAN human

14. The Turing Test “I believe that at the end of the century 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.” - Turing 1950 Questions Responses I H? / C?

15. Thinking vs. “Thinking” © The New Yorker, 5 July 1993

16. Thinking vs. “Thinking”, cont’d. Cartoon works because: –You don’t know whom you’re communicating with via computer Nevertheless, we assume we are talking to a human –I.e., entity with human cognitive capacities = Turing’s point, namely: Argument from Analogy: –Solution to Problem of Other Minds = I know I think; how do I know you do? –You are otherwise like me  (probably) you are like me w.r.t. thinking

17. What Is a Computer?

19. Thinking vs. “Thinking”, cont’d. pre-1950:computers were (only) human 2000:computers are (only) machines General educated opinion: –Computers are viewed not as implementing-devices but in functional, I/O terms –Ditto for ‘think’ (more later) –BUT: it’s not really thinking (?)

20. The Chinese Room © MacroVU Press

22. The Chinese-Room Argument It’s possible to pass TT, yet not (really) think story + questions H I (in Chinese) (who can’t (native Chinese understand Ch.) speaker) + responses (Eng.) program (in fluent Chinese) for manipulating [Ch.] “squiggles”

23. Searle’s Chinese-Room Argument (s1) Computer programs just manipulate symbols (s2) Understanding has to do with meaning (s3) Symbol manipulation alone is not sufficient for meaning (s4)  No computer program can understand ¬ (s3): You can understand just by manipulating symbols!

24. Contextual Vocabulary Acquisition Could Searle-in-the-room figure out a meaning for an unknown squiggle? Yes! –Same way you can figure out a meaning for an unfamiliar word from context

25. What Does ‘Brachet’ Mean? (From Malory’s Morte D’Arthur [page # in brackets]) 1. There came a white hart running into the hall with a white brachet next to him, and thirty couples of black hounds came running after them. [66] 2.As the hart went by the sideboard, the white brachet bit him. [66] 3.The knight arose, took up the brachet and rode away with the brachet. [66] 4.A lady came in and cried aloud to King Arthur, “Sire, the brachet is mine”. [66] 10.There was the white brachet which bayed at him fast. [72] 18. The hart lay dead; a brachet was biting on his throat, and other hounds came behind. [86]

26. Cassie learns what “brachet” means: Background info about:harts, animals, King Arthur, etc. No info about:brachets Input:formal-language (SNePS) version of simplified English A hart runs into King Arthur’s hall. In the story, B12 is a hart. In the story, B13 is a hall. In the story, B13 is King Arthur’s. In the story, B12 runs into B13. A white brachet is next to the hart. In the story, B14 is a brachet. In the story, B14 has the property “white”. Therefore, brachets are physical objects. (deduced while reading; PK:Cassie believes that only physical objects have color)

27. --> (defineNoun "brachet") Definition of brachet: Class Inclusions: phys obj, Possible Properties: white, Possibly Similar Items: animal, mammal, deer, horse, pony, dog, I.e., a brachet is a physical object that can be white and that might be like an animal, mammal, deer, horse, pony, or dog

28. A hart runs into King Arthur’s hall. A white brachet is next to the hart. The brachet bites the hart’s buttock. [PK: Only animals bite] --> (defineNoun "brachet") Definition of brachet: Class Inclusions: animal, Possible Actions: bite buttock, Possible Properties: white, Possibly Similar Items: mammal, pony,

29. A hart runs into King Arthur’s hall. A white brachet is next to the hart. The brachet bites the hart’s buttock. The knight picks up the brachet. The knight carries the brachet. [PK: Only small things can be picked up/carried] --> (defineNoun "brachet") Definition of brachet: Class Inclusions: animal, Possible Actions: bite buttock, Possible Properties: small, white, Possibly Similar Items: mammal, pony,

30. A hart runs into King Arthur’s hall. A white brachet is next to the hart. The brachet bites the hart’s buttock. The knight picks up the brachet. The knight carries the brachet. The lady says that she wants the brachet. [PK: Only valuable things are wanted] --> (defineNoun "brachet") Definition of brachet: Class Inclusions: animal, Possible Actions: bite buttock, Possible Properties: valuable, small, white, Possibly Similar Items: mammal, pony,

31. A hart runs into King Arthur’s hall. A white brachet is next to the hart. The brachet bites the hart’s buttock. The knight picks up the brachet. The knight carries the brachet. The lady says that she wants the brachet. The brachet bays at Sir Tor. [PK: Only hunting dogs bay] --> (defineNoun "brachet") Definition of brachet: Class Inclusions: hound, dog, Possible Actions: bite buttock, bay, hunt, Possible Properties: valuable, small, white, I.e. A brachet is a hound (a kind of dog) that can bite, bay, and hunt, and that may be valuable, small, and white.

32. CVA as Symbol Manipulation We “solved” each sentence for the unknown word –in terms of the rest of the text together with our background knowledge Just as we can solve an algebra problem –in terms of the rest of the equation By manipulating symbols –which is what computers do!

33. Computational Natural-Language Understanding What else is needed? –besides symbol manipulation

34. Mind as a Symbol-Manipulation System To understand language, a cognitive agent must: Take discourse as input Understand ungrammatical input Make inferences & revise beliefs Make plans –For speech acts –To ask/answer questions –To initiate conversation Understand plans –Speech-act plans of interlocutor Construct user model Learn (about world, language) Have background/world/commonsense knowledge Remember –What it heard, learned, inferred, revised = have a mind! All of this can be done by computers manipulating symbols!

35. The End ?

36. A Natural-Language-Understanding Puzzle Mice eat cheese. Which mice? –Mice that cats chase eat cheese. –Mice cats chase eat cheese

37. An NLU Puzzle (cont’d) Dogs dogs dog dog dogs. –To “dog” = to follow someone or something closely –Dogs (that other dogs follow) follow (other) dogs

38. An NLU Puzzle (cont’d) Buffalo buffalo buffalo buffalo buffalo –to “buffalo” = to intimidate someone or something –Buffalo (that other buffalo intimidate) intimidate (other) buffalo.

39. An NLU Puzzle (cont’d) What about the buffalo in the Buffalo zoo? –They are the Buffalo buffalo. –They are very intimidating! –Buffalo buffalo Buffalo buffalo buffalo buffalo Buffalo buffalo Buffalo in the Buffalo zoo (the Buffalo buffalo), who are intimidated by other Buffalo buffalo, also intimidate other Buffalo buffalo.

40. An NLU Puzzle (cont’d) The Buffalo buffalo intimidate in a very special way, called “Buffalo buffaloing” Buffalo buffalo Buffalo buffalo Buffalo buffalo Buffalo buffalo Buffalo buffalo –The Buffalo buffalo, who are buffaloed in the Buffalo way by other Buffalo buffalo, buffalo other Buffalo buffalo in the Buffalo way :-)