Minds, Machines and Turing: The Indistinguishability of Indistinguishables

Harnad, Stevan (2001) Minds, Machines and Turing: The Indistinguishability of Indistinguishables. [Journal (Paginated)]

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Turing's celebrated 1950 paper proposes a very general methodological criterion for modelling mental function: total functional equivalence and indistinguishability. His criterion gives rise to a hierarchy of Turing Tests, from subtotal ("toy") fragments of our functions (t1), to total symbolic (pen-pal) function (T2 -- the standard Turing Test), to total external sensorimotor (robotic) function (T3), to total internal microfunction (T4), to total indistinguishability in every empirically discernible respect (T5). This is a "reverse-engineering" hierarchy of (decreasing) empirical underdetermination of the theory by the data. Level t1 is clearly too underdetermined, T2 is vulnerable to a counterexample (Searle's Chinese Room Argument), and T4 and T5 are arbitrarily overdetermined. Hence T3 is the appropriate target level for cognitive science. When it is reached, however, there will still remain more unanswerable questions than when Physics reaches its Grand Unified Theory of Everything (GUTE), because of the mind/body problem and the other-minds problem, both of which are inherent in this empirical domain, even though Turing hardly mentions them.

Commentary on:Turing, A. M. (1950) Computing Machinery and Intelligence. [Journal (Paginated)]
Item Type:Journal (Paginated)
Keywords:cognitivism, computationalism, consciousness, epiphenomenalism, intelligence, machines, mind/body problem, other minds problem, philosophy of science, qualia, reverse engineering, robotics, Searle, symbol grounding, Turing Test, underdetermination, Zombies
Subjects:Psychology > Cognitive Psychology
Philosophy > Philosophy of Mind
Computer Science > Artificial Intelligence
Computer Science > Robotics
ID Code:2615
Deposited By:Harnad, Stevan
Deposited On:21 Nov 2002
Last Modified:11 Mar 2011 08:55

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Alcock, J.E. (1987) Parapsychology: Science of the anomalous or search for the soul? Behavioral and Brain Sciences 10 (4): 553-565.

Black M. (1952) The Identity of Indiscernibles. Mind 61: 152-164.

Crockett, L. (1994). The Turing Test and the Frame Problem: AI's Mistaken Understanding of Intelligence. Norwood, NJ: Ablex.

Davidson, D. (1990) Turing's Test. In: "Modelling the mind." Karim A. Mohyeldin Said, W. H. Newton-Smith, R. Viale, K. V. Wilkes (Eds.) Clarendon Press/Oxford University Press, Oxford, England. (Cognitive Science Seminars, 1985, U Oxford, Oxford, England) 1990. p. 1-11.

Dennett, D. (1985). Can machines think? P. 121. In How We Know. (ed.) M. Shafto. San Francisco, CA: Harper & Row.

Dennett, D.C. (1994) Cognitive Science as Reverse Engineering. Proceedings of the 9th International Congress of Logic, Methodology and Philosophy of Science. Pp. 679-689. Ed. D. Prawitz, B. Skyrms, and D. Westerstahl. North-Holland.

Dennett, D.C. & Kinsbourne, M. (1995). Time and the observer: The where and when of consciousness in the brain. Behavioral and Brain Sciences 15 (2): 183-247.

French, R. (1990). Subcognition and the limits of the Turing Test. Mind, 99(393):53-65.

Hadamard, J. (1949) An essay on the psychology of invention in the mathematical field. Princeton University Press.

Harnad, S. (1982a) Neoconstructivism: A unifying theme for the cognitive sciences. In: Language, mind and brain (T. Simon & R. Scholes, eds., Hillsdale NJ: Erlbaum), 1 - 11.

Harnad, S. (1982b) Consciousness: An afterthought. Cognition and Brain Theory 5: 29 - 47.

Harnad, S. (1984) Verifying machines' minds. (Review of J. T. Culbertson, Consciousness: Natural and artificial, NY: Libra 1982.) Contemporary Psychology 29: 389 - 391.

Harnad, S. (1985) Bugs, Slugs, Computers and Consciousness. American Psychologist 73(2): 21

Harnad, S. (1989) Minds, Machines and Searle. Journal of Theoretical and Experimental Artificial Intelligence 1: 5-25.

Harnad, S. (1990a) The Symbol Grounding Problem. Physica D 42: 335-346.

Harnad, S. (1990b) Against Computational Hermeneutics. (Invited commentary on Eric Dietrich's Computationalism) Social Epistemology 4: 167-172.

Harnad, S. (1990c) Lost in the hermeneutic hall of mirrors. Invited Commentary on: Michael Dyer: Minds, Machines, Searle and Harnad. Journal of Experimental and Theoretical Artificial Intelligence 2: 321 - 327.

Harnad, S. (1991) Other bodies, Other minds: A machine incarnation of an old philosophical problem. Minds and Machines 1: 43-54.

Harnad, S. (1992a) Connecting Object to Symbol in Modeling Cognition. In: A. Clark and R. Lutz (Eds) Connectionism in Context. Springer Verlag, pp 75 - 90.

Harnad, S. (1992b) The Turing Test Is Not A Trick: Turing Indistinguishability Is A Scientific Criterion. SIGART Bulletin 3(4) (October) 9 - 10.

Harnad, S. (1993a) Grounding Symbols in the Analog World with Neural Nets. Think 2(1) 12 - 78 (Special issue on "Connectionism versus Symbolism," D.M.W. Powers & P.A. Flach, eds.).

Harnad, S. (1993b) Artificial Life: Synthetic Versus Virtual. In: Artificial Life III. Proceedings of the Workshop on Artificial Life. Ed. Chris Langton. Santa Fe Institute Studies in the Sciences of Complexity. Volume XVI. Reading, Mass.: Addison-Wesley, Advanced Book Program 1994.

Harnad S. (1993c) Discussion (passim) In: Bock, G.R. & Marsh, J. (Eds.) Experimental and Theoretical Studies of Consciousness. CIBA Foundation Symposium 174. Chichester: Wiley

Harnad, S. (1994a) Levels of Functional Equivalence in Reverse Bioengineering: The Darwinian Turing Test for Artificial Life. Artificial Life 1(3): 293-301. Reprinted in: C.G. Langton (Ed.). Artificial Life: An Overview. MIT Press 1995.

Harnad, S. (1994b) Computation Is Just Interpretable Symbol Manipulation: Cognition Isn't. Special Issue on "What Is Computation" Minds and Machines 4:379-390

Harnad, S, (1995a) Does the Mind Piggy-Back on Robotic and Symbolic Capacity? In: H. Morowitz (ed.) "The Mind, the Brain, and Complex Adaptive Systems." Santa Fe Institute Studies in the Sciences of Complexity. Volume XXII. P. 204-220.

Harnad, S. (1995b) Why and How We Are Not Zombies. Journal of Consciousness Studies 1: 164-167.

Harnad, S. (1996) The Origin of Words: A Psychophysical Hypothesis In Velichkovsky B & Rumbaugh, D. (Eds.) Communicating Meaning: Evolution and Development of Language. NJ: Erlbaum: pp 27-44.

Harnad, S. (2000a) Turing Indistinguishability and the Blind Watchmaker. In: Mulhauser, G. (ed.) Evolving Consciousness Amsterdam: John Benjamins (in press)

Harnad, S. (2000b) What's Wrong and Right About Searle's Chinese Room Argument? (M. Bishop & J. Preston, eds.)

Harnad, S. (2000) Correlation VS. Causality: How/Why the Mind/Body Problem Is Hard. [Invited Commentary of Humphrey, N. "How to Solve the Mind-Body Problem"] Journal of Consciousness Studies 7(4): 54-61.

Harnad, S., Doty, R.W., Goldstein, L., Jaynes, J. & Krauthamer, G. (eds.) (1977) Lateralization in the nervous system. New York: Academic Press.

Hauser, L. (1993). Reaping the whirlwind: Reply to Harnad's "Other bodies, other minds" Minds and Machines, 3:219-237.

Hayes, P., Harnad, S., Perlis, D. & Block, N. (1992) Virtual Symposium on Virtual Mind. Minds and Machines 2: 217-238.

Heyes, C. M. (1998). Theory of mind in nonhuman primates. Behavioral and Brain Sciences 21 (1): 101-134.

Loebner, H.G. (1994) Lessons from a restricted turing test - In response. Communications of the ACM 37(6): 79-82

J.R. Lucas (1961) Minds, Machines and Goedel. Philosophy 36 112-127.

Mitchell, R.W. & Anderson, J.R. (1998) Primate theory of mind is a Turing test. Behavioral and Brain Sciences 21 (1) 127-128.

Nagel, T. (1974) What is is like to be a bat? Philosophical Review 83: 435-451.

Newell, A. (1980) Physical Symbol Systems. Cognitive Science 4: 135 - 83.

Pylyshyn, Z. W. (1980) Computation and cognition: Issues in the foundations of cognitive science. Behavioral and Brain Sciences 3: 111-169

Pylyshyn, Z. W. (1984) Computation and cognition. Cambridge MA: MIT/Bradford

Pylyshyn, Z. W. (Ed.) (1987) The robot's dilemma: The frame problem in artificial intelligence. Norwood NJ: Ablex

Schweizer, P. (1998). The Truly Total Turing Test. Minds and Machines, 8:263-272, 1998.

Searle, John. R. (1980) Minds, brains, and programs. Behavioral and Brain Sciences 3 (3): 417-457

Searle, John R. (1984). Minds, Brains and Science. Harvard University Press, Cambridge, Mass.

Searle, John R. (1993) The Failures of Computationalism. THINK 2(1)

Searle, John R. (1990) Consciousness, Explanatory Inversion, and Cognitive Science", Behavioral and Brain Sciences 13: 585-642

Shieber, Stuart M. (1994) Lessons from a restricted Turing test. Communications of the ACM 37, 70-78.

Steklis, H.D. & Harnad, S. (1976) From hand to mouth: Some critical stages in the evolution of language. In: Harnad, S., Steklis, H. D. & Lancaster, J. B. (eds.) Origins and Evolution of Language and Speech. Annals of the New York Academy of Sciences 280.

Turing, A.M. (1950) Computing Machinery and Intelligence. Mind 49 433-460 [Reprinted in Minds and machines. A. Anderson (ed.), Engelwood Cliffs NJ: Prentice Hall, 1964.]

Watt, S. (1996) Naive Psychology and the Inverted Turing Test. PSYCOLOQUY 7(14)

Wimsatt, W. K. (1954) The verbal icon: studies in the meaning of poetry. University Press of Kentucky 1954.


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