 Finally, another significant development related to the ‘accretion’ is its connection with the ‘knowing that one knows’ principle in epistemic logic, first introduced in Jaakko Hintikka’s ground-breaking Knowledge and Belief (Hintikka 1962). Hintikka argued for the equivalence between ‘I know that p’ and ‘I know that I know that p’ or, more generally, that ‘i knows that p’ (Kip) implies ‘i knows that i knows that p’ (KiKip) (Hintikka 1962, chap. 5). In connection with this, he noticed that Prichard’s introduction the idea of “reflection” (see Prichard (1950, 88) quoted above) turns the argument into an argument from introspection that does not sustain the more general claim that ‘i believes that p’ (Bip) implies ‘i knows that i believes that p’ (KiBip) (Hintikka 1962, 109–110). Still, Hintikka thought that Cook Wilson and Prichard would be right, if their remarks were to be understood as restricted to the case where i is the first-person pronoun ‘I’ (Hintikka 1962, 110). 