 The creative subject allows us to define, for a given proposition \(p\), a binary sequence \(\langle a_n\rangle\) by \(a_n = 1\) if the creative subject has a proof of \(p\) at stage \(n\); \(a_n = 0\) otherwise. Now if the construction of these sequences is the only use made of the creative subject, then references to the latter may be avoided by postulating the principle known as Kripke’s Scheme