DE RUGGIERO, GUIDO. – Historian of philosophy and publicist, born in Naples on 23 March 1888, died in Rome on 29 December 1948. Professor of the history of philosophy, first at the Magistero, then in the Faculty of Letters at Rome. At first an actualist, of a form of actualism more intransigent than Gentile’s, he subsequently drew closer to Croce’s historicism. Later (Revisioni idealistiche, in Educazione nazionale, 3 [1933]) he rejected the reduction of philosophy to a methodology of history and endeavoured to assert the realistic exigency within idealism itself (Il ritorno alla ragione, Bari 1946): reason is not wholly immanent in the flow of reality (historical reason), but is, at the same time, transcendent (metahistorical reason); by placing himself at the apex of supreme values, man measures the insufficiency of what is in relation to what ought to be.
To D. R. is owed (and this is his most important work) a Storia della filosofia (Bari 1920 ff.) in 15 volumes. The dialectical method and the idealistic point of view often compel D. R. to adopt one-sided interpretations that do not correspond to historical objectivity (especially in the volumes on ancient and Christian thought); nor are hackneyed commonplaces of secularist rationalism lacking (particularly in the volumes on the Reformation and Counter-Reformation). The bibliography on which D. R. draws is almost exclusively limited to idealistic and Protestant works. Among his writings on the history of political thought, mention should be made of the Storia del liberalismo europeo (2nd ed., Bari 1944).