Chisholm wrote and taught in a distinctive style that inspired his readers and students. His characteristic methodology was to begin his discussion of a philosophical issue by identifying a few key questions and citing pre-analytic data that an adequate theory should accommodate. In many cases his work began in the Aristotelian fashion with a set of “aporia” or puzzles. He sought to develop a theory that would be adequate to the puzzles. He formulated his theories by first introducing a small number of primitive or unanalyzed terms and then constructing an often elaborate system of definitions and principles all built on these primitives. The final principles and definitions were intended to provide the basis for solutions to the puzzles with which he began. The clarity and elegance of the systems were remarkable, though in some cases critics worried that the primitive concepts were for one reason or another suspect. Chisholm encouraged readers and students to criticize his systems by proposing counterexamples and objections. They were eager to do so, and Chisholm took great joy in revising and improving upon his views in the light of their comments.