Alan Turing and the Thinking Machine

1. Alan Turing and the Thinking Machine Prof. Dr. Martin Peterson Section for Philosophy and Ethics TU/e

2. Alan Turing (1912 – 1954) Some achievements: • The Turing Test (”the imitation test”) • The Turing Machine • ENIGMA (WWII code)

3. Can machines think? • We should replace the question ”Can machines think” by the ”Imitation game”!

4. The Imitation Game Q: Please write me a sonnet on the subject of the ForthBridge. A : Count me out on this one. I never could write poetry. Q : Add 34957 to 70764 A : (Pause about 30 seconds and then give as answer) 105621. Q : Do you play chess ? A: Yes. Q : I have K at my Kl, and no other pieces. You have only K at K6 and R at Rl. It is your move. What do you play? A : (After a pause of 15 seconds) R-R8 mate.

5. ELIZA Written by Joseph Weizenbaum 1964-66

6. John Searle (1932 - )

7. The Chinese Room Argument • Producing correct output is not sufficient for thinking!

8. Objection: The Systems Reply: "While it is true that the individual person who is locked in the room does not understand the story, the fact is that he is merely part of a whole system, and the system does understand the story.” Searle: “Let the individual internalize all of these elements of the system.”

9. Mark Sprevak

10. Sprevak on Searle 1(2) AI. Running a program is sufficient for, or constitutive of, understanding Chinese Stories. G. The man inside the Chinese room can run anyprogram. • Therefore, the man inside the room can understand Chinese stories. ------------------------------------ But this can’t be. Either AI or G must be false. G is true, therefore AI must be false.

11. Sprevak on Searle 2(2) AI. Running a program is sufficient for, or constitutive of, understanding Chinese Stories. G**. The man inside the Chinese room can run at least one program constitutive of understanding. • Therefore, the man inside the room can understand Chinese stories. ------------------------------------ But this can’t be. Either AI or G must be false. G is true, therefore AI must be false.

12. Sprevak’s Main Point “A Chinese room can reproduce the input–output behaviour of any Chinese speaker, but what Searle needs is for the Chinese room to reproduce that input–output pattern in the same way—to run the same programs—as a Chinese speaker. In particular, Searle needs the Chinese room to be able to run any program that Strong AI claims is constitutive of understanding.”

13. Sprevak on Atomic Operations “Another source of difference is that the two systems may support different types of atomic operation. As specified by Searle, the Chinese room supports the atomic operations compare, copy, and concatenate. There seems no reason why the brain should support only these operations. If there is any difference in the atomic operations supported, then the individual steps in the two programs cannot be the same, creating problems for the notion that the two machines can run the same program.”

14. Conclusion • Searle is, according to Sprevak, wrong: ”Searle’s Chinese room argument fails because G … is false. An advocate of Strong AI need not admit that even one program that is putatively constitutive of understanding can be run on a Chinese room. The architecture of brains and Chinese rooms is too different.” • But does this show that Turing is right? No!!

15. References • Searle, John (1980), "Minds, Brains and Programs", Behavioral and Brain Sciences3 (3): 417–457 • Turing, Alan (October 1950), "Computing Machinery and Intelligence", MindLIX (236): 433–460. • Sprevak, Mark (2007) The British Journal for the Philosophy of Science (2007) 58, 755–776