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describing the excuse for mistake or overreaching as a rule of law is a statement that on certain factual circumstances, an otherwise okay contract will not be enforced: for prediction purposes it is unnecessary to consider why non-enforcement follows from mistake or over-reaching

however, if one wishes to explain why the law-giver gave the rule for mistake/overreaching, a possible explanation is implied mutual intent and the higher rule that contract enforcement is to serve intention. but only if the law-maker has some empirical foundation for a particular implied intent [implausible as a mutual intent in the overreaching case] is that intent an explanation: if the lawmaker implies the intent not because he believes it to be true, but because he wishes it were true [a natural law position?] or wishes that he could think of another contract excuse, the intent thus imputed is not an explanation but the beginning of another inquiry???