Introduction to AI & AI Principles (Semester 1) WEEK 3 John Barnden Professor of Artificial Intelligence School of Computer Science University of Birmingham, UK

WHAT DOES “ARTIFICIAL” MEAN??

Links to Other Disciplines uPsychology: on how human and other animal minds and behaviour work. uPhysiology & Neurophysiology: on how bodies & brains work. uPhilosophy: on the nature of mind, thought, consciousness, language, morality, imagination, reasoning, representation, … uLinguistics: on the nature of communication via language uSociology: on the nature and operation of society uothers

How Do the Aims of AI Differ from those of the Rest of CS? uSystem ability on broader tasks or broader ranges of tasks; Extrapolation to new variants of tasks. uVariable organization of major actions. uAdaptability, learning. uHandling of imperfections: uncertainty, vagueness, inconsistency, incorrectness, missing info, system damage. u“Graceful degradation” as info or system damage gets worse. u“Satisficing”: being good enough rather than perfect. uDiversity of information. uSelf-reflection.

Expert versus Everyday/Common-Sense uExpert AI: e.g., l Expert systems for medical diagnosis, etc. l Chess programs l Mathematical theorem provers l Aircraft movement planning systems l Specialized manufacturing robots uEveryday/Common-Sense AI: e.g., l Language processing, for no specific domain l Common-sense reasoning about the everyday world l Seeing the everyday world

WHY IS EVERYDAY AI CHALLENGING?

Who … … ? How many of you … … ?

Notice on van: CAUTION CHILDREN What could this mean?

Some Possible Meanings (of the phrase in isolation, at least) uBe cautious, you might harm a child. uBe cautious, a child might harm you! uChildren, be cautious. uCaution some children, please. uThis locker (say) is for the children of the Caution family. uThese are the children who have been cautioned. uThese are the children who have done some cautioning. uThese are the children who are “a caution.”

at Birmingham airport EU Nationals this way Other passports this way

Three Touching Tales uJohn got to his front door, but realized he didn’t have his key. uMary went to a restaurant for lunch. Afterwards she didn’t have enough money to take a taxi. uMary went to a restaurant for lunch. Afterwards she didn’t have enough money to buy the car she wanted.

Some Lessons from the Above uRole of context (co-text and discourse situation). uRole of extensive, diverse knowledge of the world. uEfficient, appropriate accessing of that knowledge. uRole of inference, to join things up. uRole of conjectured goals of the other participants in a conversation.

Further Difficulties with Language, 1 uNL expressions can be syntactically ambiguous. l She hit the man with the telescope. Does the prepositional phrase with the telescope “attach” to hit or to the man? l I saw that gasoline can explode. Is can a noun or a verb here? Is that a complementizer or a demonstrative determiner?

Further Difficulties with Language, 2 uLexical ambiguity: Words often have a range of distinct meanings, possibly without varying the part of speech (noun, verb, or whatever). l ball, newspaper, bank, mole, sloth,... The different meanings may or may not be related to each other. When they are: POLYSEMY. When they’re not: HOMONYMY.