Friedrich Nietzsche famously stated that “Christianity is Platonism for the masses” in his introduction to Beyond Good and Evil. His reason for giving Christianity this label was because of Christian obsession with the supreme Good talked about in Plato. This was Augustine’s summum bonum.
Nietzsche rejected Plato and other introspection orientated philosophy. It was in this context he made his famous remark:
Let us not be ungrateful to it, although it must certainly be confessed that the worst, the most tiresome, and the most dangerous of errors hitherto has been a dogmatist error–namely, Plato’s invention of Pure Spirit and the Good in Itself. But now when it has been surmounted, when Europe, rid of this nightmare, can again draw breath freely and at least enjoy a healthier–sleep, we, WHOSE DUTY IS WAKEFULNESS ITSELF, are the heirs of all the strength which the struggle against this error has fostered. It amounted to the very inversion of truth, and the denial of the PERSPECTIVE–the fundamental condition–of life, to speak of Spirit and the Good as Plato spoke of them… But the struggle against Plato, or–to speak plainer, and for the “people”–the struggle against the ecclesiastical oppression of millenniums of Christianity (FOR CHRISITIANITY IS PLATONISM FOR THE “PEOPLE”), produced in Europe a magnificent tension of soul, such as had not existed anywhere previously; with such a tensely strained bow one can now aim at the furthest goals.
Although Nietzsche was a nihilist, he correctly saw modern Christianity as an infantile version of Platonism.