âReflective Oracles: A Foundation for Classical Game Theoryâ, 2015-08-17 (; backlinks; similar)â :
Classical game theory treats players as specialâa description of a game contains a full, explicit enumeration of all playersâeven though in the real world, âplayersâ are no more fundamentally special than rocks or clouds. It isnât trivial to find a decision-theoretic foundation for game theory in which an agentâs co-players are a non-distinguished part of the agentâs environment. Attempts to model both players and the environment as Turing machines, for example, fail for standard diagonalization reasons.
In this paper, we introduce a âreflectiveâ type of oracle, which is able to answer questions about the outputs of oracle machines with access to the same oracle. These oracles avoid diagonalization by answering some queries randomly. We show that machines with access to a reflective oracle can be used to define rational agents using causal decision theory. These agents model their environment as a probabilistic oracle machine, which may contain other agents as a non-distinguished part.
We show that if such agents interact, they will play a Nash equilibrium, with the randomization in mixed strategies coming from the randomization in the oracleâs answers. This can be seen as providing a foundation for classical game theory in which players arenât special.