The term “perennial philosophy” . . . refers to a fourfold realization: (1) there is only one Reality (call it, among other names, God, Mother, Tao, Allah, Dharmakaya, Brahman, or Great Spirit) that is the source and substance of all creation; (2) that while each of us is a manifestation of this Reality, most of us identify with something much smaller, that is, our culturally conditioned individual ego; (3) that this identification with the smaller self gives rise to needless anxiety, unnecessary suffering, and cross-cultural competition and violence; and (4) that peace, compassion, and justice naturally replace anxiety, needless suffering, competition, and violence when we realize our true nature as a manifestation of this singular Reality. The great sages and mystics of every civilization throughout human history have taught these truths in the language of their time and culture. —Rami Shapiro 

Rami Shapiro, Perennial Wisdom for the Spiritually Independent: Sacred Teachings—Annotated & Explained (Skylight Paths Publishing: 2013), xiv.