Detecting design: Fast and frugal or all things considered?

Within the Cognitive Science of Religion, Justin Barrett has proposed that humans possess a hyperactive agency detection device that was selected for in our evolutionary past because ‘over detecting’ (as opposed to ‘under detecting’) the existence of a predator conferred a survival advantage. Within the Intelligent Design debate, William Dembski has proposed the law of small probability, which states that specified events of small probability do not occur by chance. Within the Fine-Tuning debate, John Leslie has asserted a tidiness principle such that, if we can think of a good explanation for some state of affairs, then an explanation is needed for that state of affairs. In this paper I examine similarities between these three proposals and suggest that they can all be explained with reference to the existence of an explanation attribution module in the human mind. The forgoing analysis is considered with reference to a contrast between classical rationality and what Gerd Gigerenzer and others have called ecological rationality.