 In addition to these contributions to mathematics Frank Ramsey (1925a) devoted much effort to addressing what were by then seen as problems in Whitehead &amp; Russell’s attempt in their Principia Mathematica (1910–1913), to base mathematics on formal logic, an enterprise which Ramsey initially strongly supported though he ultimately became disappointed with his efforts to correct its shortcomings, see Paul 2012 (232). Since then this approach to the foundations of mathematics has been very largely overshadowed amongst mathematicians by the practically simpler device of assuming as a foundation Zermelo-Fraenkel Set Theory.