******* Language, Cognition, and Computation Lecture Series *******

 
Title                        Newcomb’s Problem and Deterministic Choice:
                                  Implications for Cognitive Design

Speaker                        Gary Drescher

Date                        Friday, May 28, 2004

Time                         3:00pm

Location                E15-070 (Bartos Theater)


Abstract

Newcomb’s Problem, a long-standing decision-theoretic paradox, posits
an imaginary situation in which a simulator can reliably predict your
actions. A large reward was previously irrevocably set up for you if
and only if the simulator’s prediction was that you would now make a
choice which (apart from the large reward) is slightly unfavorable to
you. A dilemma arises as to whether to make the choice that (almost
certainly) implies that you reap the large reward, even though the
choice does notcauseyour obtaining that reward.

The paradox bears on the compatibility of choice and determinism, a
quintessentially philosophical problem. But it also has important
ramifications for the science and engineering of cognition. Newcomb’s
Problem illuminates a fundamental controversy about the foundations of
decision theory, which translates into a central question about the
design of intelligent, choice-making agents. What sort of relation
between contemplated action and goal--causal, subjunctive, evidential,
or some other relation--must hold for it to be sensible to consider the
action ameansto the goal? That is, what constitutes a means-end
relation? And how might an agent that learns independently recognize
when this relation holds?

By appeal to relatively mundane, uncontroversial scenarios, I argue
against evidential and causal criteria for linking means to ends, and
propose instead a subjunctive criterion: an agent acts for the sake of
whatwouldbe the case if this or that action were taken, which (I argue)
is sometimes distinct from what an action either causes or gives
evidence of. I sketch a computational implementation of subjunctive
means-end recognition, and show how the proposed mechanism might
resolve Newcomb’s Problem.
 

Bio
 
Gary Drescher received his Ph.D. at the MIT AI Lab. His dissertation
proposed empirical-learning and concept-inventing machinery to account
for aspects of Piagetian cognitive development during infancy. Drescher
is the author of Made-Up Minds: A Constructivist Approach to Artificial
Intelligence. Now indulging in amateur philosophy, he is a visiting
fellow at the Center for Cognitive Studies at Tufts.


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