Artificial Intelligence Intro and Topics

1. Artificial IntelligenceIntro and Topics Artificial Intelligence Lecture 1: AI Intro and TOPICS

2. AI – The Movie • The AI film by Spielberg was based on a story by Brian Aldiss ‘Supertoys last all summer long’ written in 1969. • Recently, he wrote: ‘Brains are far more than mere computers… Intelligence cannot exist without consciousness. Artificial consciousness: that sounds like a taller order, and indeed it is. … So what I believed in 1969 is what I do not believe in 2001’ (New Scientist 09/15/01). Artificial Intelligence Lecture 1: Artificial Intelligence Intro and Topics

3. AI – The History • AI is nearly as old as computing • 1941 Konrad Zuse, Germany, general purpose computer • 1943 Britain (Turing and others) Colossus, for decoding • 1945 ENIAC, US. John von Neumann a consultant • 1956 Dartmouth Conference organized by John McCarthy (inventor of LISP) • The term Artificial Intelligence was coined at Dartmouth, which was intended as a two month study. Artificial Intelligence Lecture 1: Artificial Intelligence Intro and Topics

4. AI – The Achievements • Intelligent Robots make cars in all advanced countries. • Reasonable machine translation is available for a large range of foreign web pages. • Computers land 200 ton jumbo jets unaided every few minutes. • Search systems like Google are not perfect but provide very effective information retrieval • Robots cut slots for hip joints better than surgeons. • Deep blue beat Kasparov in 1997 and the current world Go champion is a computer. • Medical expert systems can outperform doctors in many areas of diagnosis. Artificial Intelligence Lecture 1: Artificial Intelligence Intro and Topics

5. AI – A Comment Despite all these achievements, one of the major philosophers of Cognitive Science wrote recently: “… the failure of artificial intelligence to produce successful simulation of routine commonsense cognitive competences is notorious, not to say scandalous. We still don't have the fabled machine that can make breakfast without burning down the house; or the one that can translate everyday English into everyday Italian, or the one that can summarize texts..” (Jerry Fodor, The Mind doesn’t Work that Way, 2000, p.37). Artificial Intelligence Lecture 1: Artificial Intelligence Intro and Topics

6. What is Artificial Intelligence? • The use of computer programs and programming techniques to cast light on the principles of intelligence in general and human thought in particular (Boden) • The study of intelligence independent of its embodiment in humans, animals or machines (McCarthy) • The pursuit of metaphysics by other means (Longuet-Higgins) • AI is the study of how to do things which at the moment people do better (Rich & Knight) • AI is the science of making machines do things that would require intelligence if done by men. (Minsky) Artificial Intelligence Lecture 1: Artificial Intelligence Intro and Topics

7. What is Artificial Intelligence? Two approaches • Those who think AI is the only serious way of finding out how we work and • Those who want computers to do very smart things, independently of how we work. This is the important distinction betweenCognitive Scientists vs. AIEngineers. Artificial Intelligence Lecture 1: Artificial Intelligence Intro and Topics

8. Attacks on AI Part I : Lucas: Minds, Machines & Gödel Part II: Searle: Minds, Brains & Programs Part III: Weizenbaum : Computer Power & Human Reason

9. Strong AI and Weak AI • Phrases coined by John Searle • Weak AI takes the view that … • Computers are powerful tools • to do things that humans otherwise do • and to study the nature of minds in general • Strong AI takes the view that • A computer with the right software is a mind • Lucas and Searle attack Strong AI • Weizenbaum attacks all AI

10. Minds, Machines and Gödel • Title of article by J.R. Lucas • reprinted in `Minds and Machines’, ed. A.R. Anderson • Prentice Hall, 1964 • Argument is based on the following premises • 1. Gödel’s theorem shows that any consistent and powerful formal system must be limited • there must be true statements it cannot prove • 2. Computers are formal systems • 3. Minds have no limit on their abilities

11. Minds, Machines and Gödel • Premises • 1. Gödel’s theorem shows that any consistent and powerful formal system must be limited • there must be true statements in cannot prove • 2. Computers are formal systems • 3. Minds have no limit on their abilities • Conclusion • Computers cannot have minds • Should Strong AI give up and go home? • Certainly Gödel’s theorem applies to computers

12. Refuting Lucas: (1) • Turing decisively refuted Lucas • in his article `Computing Machinery and Intelligence’ • The defeat is on two counts • 1. “Although it is established that there are limitations to the powers of any particular machine, it has only been stated without any sort of proof, that no such limitations apply to the human intellect” • i.e. are we sure humans can prove alltrue theorems? • Maybe humans are unlimited? What then?

13. Refuting Lucas: (2) • Turing’s second point is decisive • “We too often give wrong answers ourselves (to be justified in being very pleased at such evidence of fallibility on the part of machines).” • Gödel’s theorem applies only to consistent formal systems • Humans often utter untrue statements • We might be unlimited formal systems which make errors • The two arguments show that Lucas’s attack fails • Strong AI’ers don’t need to worry about Gödel’s theorem

14. The Chinese Room • John Searle • “Minds, Brains, and Programs” • The Behavioral and Brain Sciences, vol 3, 1980 • Searle attacked with the ‘Chinese Room’ argument • Remember, Searle is attacking Strong AI • he attacks claims that, e.g. story understanding programs • literally understand stories • explain human understanding of stories

15. The Chinese Room Thought Experiment • A thought experiment • Aimed at showing conscious computers are impossible • By analogy with an obviously ridiculous situation • John Searle does not understand Chinese • Imagine a set up in which he can simulate a Chinese speaker

16. Locked in a Chinese Room • John Searle is locked in solitary confinement • He is given lots of … • blank paper, pens, and time • lots of Chinese symbols on bits of paper • an in tray and out tray • for receiving and sending Chinese messages • rule books written in English (which he does understand) • telling how to take paper from in-tray, process it, and put new bit of paper with symbols on it in out-tray

17. Outside the Chinese Room • Unknown to Searle, his jailers … • regard the in-tray as containing input from a Chinese player of Turing’s imitation game • the rule books as containing an AI program • regard the out-tray as containing responses • Suppose Searle passes the Turing Test in Chinese • But Searle still does not understand Chinese • By analogy, even a computer program that passes the Turing test does not truly “understand”

18. Objections and Responses • Like Turing, Searle considers various objections • 1. The Systems Reply • “The whole system (inc. books, paper) understands” • Searle: learn all rules and do calculations all in head • still Searle (I.e. whole system) does not understand • 2. The Robot Reply • “Put a computer inside a robot with camera, sensors etc” • Searle: put a radio link to the room inside the robot • still Searle (robot’s brain) does not understand

19. Objections and Responses • 3. The Brain Simulator Reply • “Make computer simulate neurons, not AI programs” • In passing: Searle notes this is a strange reply • seems to abandon AI after all! • Searle: there is no link between mental states and their ability to affect states of the world • “As long as it simulates only the formal structure of a sequence of neuron firings … it won’t have simulated what matters about the brain, namely its causal properties, its ability to produce intentional states” • “intentional states”: that feature of mental states by which they are directed at states of affairs in the world

20. Joseph Weizenbaum • “Computer Power and Human Reason” • Penguin, 1976 (second edition 1985) • Weizenbaum wrote ELIZA in mid 1960’s • Shocked by reactions to such a simple program • people wanted private conversations • therapists suggested use of automated therapy programs • people believed ELIZA solved natural language understanding

21. Computer Power and Human Reason • Weizenbaum does not attack possibility of AI • Attacks the use of AI programs in some situations • attacks the “imperialism of instrumental reason” • e.g. story about introduction of landmines • Scientists tried to stop carpet bombing in Vietnam • but did not feel it enough to oppose on moral grounds • so suggested an alternative to bombing namely widespread use of landmines

22. What’s the problem? • “The question here is: • ‘What human objectives and purposes may not be appropriately delegated to a computer?’ ” • He claims that the Artificial Intelligentsia claim • there is no such domain • But knowledge of the emotional impact of touching another person’s hand “involves having a hand at the very least” • Should machines without such knowledge be allowed power over us?

23. What computers shouldn’t do • Weizenbaum argues that many decisions should not be handled by computer • e.g. law cases, psychotherapy, battlefield planning • Especially because large AI programs are ‘incomprehensible’ • e.g. you may know how a Deep Blue works • but not the reason for a particular move vs Kasparov • Imperialism of instrumental reason must be avoided • especially by teachers of computer science!

24. And finally … • Weizenbaum gives an example of • “a computer application that ought to be avoided” • Wreck a nice beach • Recognise speech • system might be prohibitively expensive • e.g. too much for a large hospital • might be used by Navy to control ships by human voice • listening machines for monitoring phones.

25. Topics • Searching in State Space • Adversarial Search ( Game Search) • Constraint Satisfaction Problem • Knowledge Representation • Propositional and Predicate Logic • Learning and Reasoning • Applications Artificial Intelligence Lecture 1: Artificial Intelligence Intro and Topics