Sanātana Dharma, translated as perennial philosophy from the Latin philosophia perennis, comes from the Sanskrit, meaning “the eternal law” that sustains/upholds/surely preserve.
Perennial philosophy is a pointer to the universal recurrence of philosophical insight independent of epoch or culture, including universal truths on the nature of reality, humanity or consciousness (anthropological universals).
The term was first used by Agostino Steuco (1497–1548) who used it to title a treatise, De perenni philosophia libri X, published in 1540. Steuco drew on an already existing philosophical tradition, including the ones cultivated by Marsilio Ficino (1433–99) and Giovanni Pico della Mirandola (1463–94). Pico, a student of Ficino, embodies a more ambitious attempt to use the philosophies and theologies of the past, especially the priscia theologica. Pico went further than his teacher by suggesting that truth could be found in many, rather than just two, traditions. This proposed a harmony between the thought of Plato and Aristotle, and saw aspects of the Prisca theologia in Averroes, the Koran, the Kabbalah among other sources.
Outside the European tradition of the philosophia perennis, one of the best known traditions to propose a similar pointer is Sanatana Dharma of Hinduism. Indeed this term can be seen as the original name of Hinduism, the latter being a term invented by ancient Persians. Sanatana Dharma has also influenced the Indian conception of secularism, where the notion of ‘sarva dharma sambhava’ (all religions or truths are equal or harmonious to each other) prefers to tolerate all faiths equally rather than rejecting religion per se.