The phrase philosophia perennis is said to have been first used by Leibniz. It has been adopted and freely employed by the Catholic Neo-Thomists, for whom it means a development of the Aristotelianism, modified by strong Neoplatonic elements, which Arabian scholars transmitted to the first Renaissance in the West. It claims also to be a return to the early Christian philosophy of religion, a fusion of Hellenistic and Jewish thought, the latter itself a syncretistic religion with many Persian and other borrowings. The controversy, directed against various modern philosophies, has been conducted with great ability by such writers as Gilson, Maritain, Sheen, Watkin, Dawson and D'Arcy, whose books would perhaps have received more attention from independent thinkers, but for the suspicion which surrounds apparent attempts to revive the methods and inhibitions of the medieval schoolmen.
There has been a parallel movement in the Orthodox Eastern Church, represented in Russian by Frank, Bardyaeff, Solovioff and Lossky. These writers are more Platonic and more fearlessly mystical than the Thomists. Origen in the East has more weight than Augustine.