Process and Reality ends with a warning: ‘[t]he chief danger to philosophy is narrowness in the selection of evidence’ (PR, 337). Although this danger of narrowness might emerge from the ‘idiosyncrasies and timidities of particular authors, of particular social groups, of particular schools of thought, of particular epochs in the history of civilization’ (PR, 337), we should not be mistaken: it occurs within philosophy, in its activity, its method. And the fact that this issue arises at the end of Process and Reality reveals the ambition that has accompanied its composition: Whitehead has resisted this danger through the form and ambition of his speculative construction. The temptation of a narrowness in selection attempts to expel speculative philosophy at the same time as it haunts each part of its system.