How Intractability Spans the Cognitive and Evolutionary Levels of Explanation.

The challenge of explaining how cognition can be tractably realized is widely recognized. Classical rationality is thought to be intractable due to its assumptions of optimization and/or domain generality, and proposed solutions therefore drop one or both of these assumptions. We consider three such proposals: Resource-Rationality, the Adaptive Toolbox theory, and Massive Modularity. All three seek to ensure the tractability of cognition by shifting part of the explanation from the cognitive to the evolutionary level: Evolution is responsible for producing the tractable architecture. We consider the three proposals and show that, in each case, the intractability challenge is not thereby resolved, but only relocated from the cognitive level to the evolutionary level. We explain how non-classical accounts do not currently have the upper hand on the new playing field.