Fools act on imagination without knowledge, pedants act on knowledge without imagination.

Whitehead contrasts two intellectual failures: the “fool,” who is driven by ungrounded fancy and acts without the discipline of evidence, and the “pedant,” who clings to accumulated facts or rules but cannot creatively reimagine them. The implied ideal is a balanced mind in which imagination proposes possibilities and knowledge tests, refines, and applies them. In Whitehead’s broader philosophy of education and inquiry, progress depends on this interplay: imagination without knowledge becomes delusion, while knowledge without imagination becomes sterile repetition. The line thus functions as a compact warning against both credulity and scholastic rigidity, urging a synthesis that makes understanding both accurate and alive.