 In the preface of Introduction to the Foundations of Mathematics, Raymond Wilder (1952, iv) apologizes for the errors in the text. The 1982 reprint has three pages of errata that vindicate Wilder’s humility. D. C. Makinson (1965, 205) quotes Wilder’s 1952 apology and extracts a paradox: Wilder rationally believes each of the assertions in his book. But since Wilder regards himself as fallible, he rationally believes the conjunction of all his assertions is false. If the agglomeration principle holds, \((Bp \amp Bq) \rightarrow B(p \amp q)\), Wilder would rationally believe the conjunction of all assertions in his book and also rationally disbelieve the same thing!