Esotericism is knowledge that is only accessible to initiates, in contrast to exotericism, the knowledge of which is verifiable and accessible to everyone. Many philosophical movements and societies rely on such a form of knowledge that concerns both the individual and the cosmos and develop their own doctrine and methodology. Esoteric, occult and arcane have similar meanings and in most contexts the three terms are interchangeable. As an academic field of study, esotericism is the study of alternative or marginalized religious movements or philosophies whose adherents generally distinguish their own beliefs, practices, and experiences from public, institutionalized religious traditions. The research areas of esotericism include alchemy, astrology, Gnosticism, Hermeticism, Kabbalah, magic, mysticism, Neoplatonism, new religious movements related to these movements, nineteenth-, twentieth-, and twenty-first-century occult movements, Rosicrucians, secret societies, and Christian theosophy.