 In Lewis Carroll’s presentation of the paradox, the Tortoise refuses to infer the conclusion when faced with an instance of the rule of Modus Ponens and Achilles suggests that one should then add the rule as a further premise, but the Tortoise still refuses to infer, so that Achilles then suggest to add the whole formula resulting from adding the rule as a premise as yet a further premise to no avail, and so forth. It is often claimed that the Tortoise’s repeated refusals indicates that rules of inference are in themselves normatively inert, so that a further ingredient is needed for one to infer, e.g., a ‘‘rational insight’’ (Bonjour 1998, 106–107). Cook Wilson’s claim that one can only ‘apprehend’ the validity of the rule in a particular inference, thus ‘seeing the truth directly’ or possessing a ‘direct intuition’ (SI, 441), is an analogous move.