Bobby Fischer and the delusions of a king of logic.

Abstract

This Essay relates the intriguing story of Bobby Fischer and his severe mental illness. It does so through the lens of what appears to be a paradox: how could someone whose mind was so exquisitely tuned to the logic and strategy of chess at the elite level, develop a system of firmly held beliefs that seemed to clearly to defy logic and rationality? In fact, we suggest, the case of Bobby Fischer highlights something that is often overlooked: that delusional thinking may be underpinned not by a failure of logic but rather by a train of logic that, though internally consistent, is insufficiently constrained by past experiences and by the capacity to consider prevailing assessments of environmental uncertainty and volatility. Commemorating the 50th anniversary of his unforgettable world championship victory, we examine how his persisting brilliance on the chessboard could co-exist with his profoundly anomalous conception of reality and speculate on how informative this might prove in thinking about the mechanisms of delusion formation.