Antoine Faivre
Antoine Faivre (1934–2021) was the first scholar to hold an academic chair dedicated to Western Esotericism (at the École Pratique des Hautes Études in Paris). He provided the field with its first rigorous empirical framework.
The Four-Point Definition
To prevent "esotericism" from remaining a vague, catch-all term, Faivre proposed a strict typology. For a current of thought to be classified as esoteric, it must exhibit four intrinsic characteristics: 1) A belief in universal Correspondences (macrocosm/microcosm), 2) The concept of a Living Nature (the cosmos animated by spiritual forces), 3) The necessity of Imagination and Mediations (rituals, angels, symbols to access the divine), and 4) The experience of Transmutation (inner spiritual alchemy). While highly influential, later scholars like Hanegraaff criticized this definition as being overly tailored to Renaissance Hermeticism and Christian Theosophy, excluding later secular or psychological occultisms.