In this essay, the Author outlines the acceptance by the Italian philosophical community of the early twentieth century of Piero Martinetti’s Introduzione alla metafisica. The most extensive review of the book was written by Giovanni Gentile for La Critica. It helps us to understand some of the structural reasons distancing Gentile’s immanent idealism from Martinetti’s religious idealism, interpreted as a development of Wilhelm Schuppe’s Immanenzphilosophie. Other readers of the Introduzione alla metafisica were Antonio Aliotta, Giovanni Vidari and Aurelio Pelazza (a disciple of Martinetti). The concluding part of the essay analyzes the reading of Introduzione alla metafisica made in 1932 by Eugenio Colorni. He found in Martinetti’s book ideas for opposing absolute idealism, which had, in his opinion, unjustifiably monopolized the legacy of Kant.
Keywords: Piero Martinetti, Giovanni Gentile, Eugenio Colorni, 20th-century Italian philosophy, idealism, Immanenzphilosophie