 The feeling that there is an absolute realm of sets, somehow determined in spite of the non-existence of a complete axiomatic characterization, receives more of a blow from the solution (better, the unsolving) of the continuum problem than from the famous Gödel incompleteness theorems. It is not a question of realism… versus either conceptualism or nominalism, but if one chooses realism, whether there can be a “genetic” realism without axiomatic specification. (1966 [BE: 677]).