"From Richard McKeon and Robert Brumsbaugh I learned to view the history of philosophy as a series, not of alternative solutions to the same problems, but of quite different sets of problems. From Rudolph Carnap and Carl Hempel I learned how pseudo-problems could be revealed as such by restarting them in the formal mode of speech. From Charles Hartshorne and Paul Weiss I learned how they could be so revealed by being translated into Whiteheadian or Hegelian terms."