Esotericism is a multi-disciplinary field of spiritual knowledge contained within all religions which concerns the principles and qualities of magic and mysticism. No matter what religion (Christinaity, Islam, Hinduism, etc.), all spiritual paths have an esoteric aspect that focus on an interpersonal relationship with God, Spirit, the Divine, etc. In essence, all religion has two components within its make-up, regardless of denomination: the exoteric and esoteric. The exoteric aspect is the more public persona of a spiritual practice: its community, rituals, and liturgic practices. The esoteric side of a religion regards the inner world, the more intimate and arcane elements.
Pinpointing an exact definition of esotericism is difficult. However, an understanding can be reached by defining its two main components: mysticism and magic.
One of the most notable scholars of esotericism in the 20th Century, Manly P. Hall, wrote about mysticism in his work The Mystical Christ:
"Mysticism is not a sect or creed ; it is a conviction , deriving its authority from the natural instincts of the human heart. [...] Mysticism teaches the imminent availability of the divine power. It transforms, by a process of interpretation, all doctrines from codes into qualities of conviction." (p.1, 8)
What Hall is saying is that mysticism removes the hierarchy of institution in an organized religion and makes the religious experience personal. Mysticism denotes that a true spiritual walk should not be based on formalities, but on one's passion for connection with the Divine. Through that, a life of conscience can blossom; rather than the other way around.
When one hears the word "magic," the mind is likely to conjure images of Merlin the wizard shooting fireballs from his hands. As entertaining as that picture is, it is far cry from the actual application of magic in the esoteric disciplines. To paraphrase many of the most renowned magicians in history (Dion Fortune, W.E. Butler, Aleister Crowley, etc.) magic is simply the art of causing changes in consciousness at will. So, in many ways, there is nothing supernatural about it. In essence, magic is a system that, through symbols and ritual, speaks to the human subconscious mind and produces a deliberate change in perspective, action, and/or both in the conscious mind. Some could even say magic is an advanced form of psychology; in fact, its techniques have been utilized by psychoanalysts for over a century, including in the acclaimed Carl Jung.
Now, sometimes the word "esotericism" is used in conjunction with or synonymous to the word "occult." Unfortunately the usage of the term "occult" has been bastardized over time and is now commonly referred to connotations of Devil-worship or malignant cults. This could not be further from reality.
The word "occult" comes from the Latin word occultus which means "hidden" or "secret." It was originally used to describe that area of knowledge that dealt with the hidden realities, i.e. - the spiritual reality of God. This is because God as we know it is invisible, remains hidden, and any knowledge of God is considered "hidden" knowledge. This is the foundation of so-called "secret societies;" they do not retain secrecy in support of conspiracy against their fellow man, but to protect the fragile body of spiritual knowledge that they so practiced.
I often use the word "esoteric" and "occult" interchangeably, as do many writers and researchers, but for the purposes of sharing my own thoughts and ideas with the public I have shown the term "esoteric" when discussing this particular subject matter on my web platform.
Hope this clears up some definitions for readers. I look forward to any comments, questions, or conversation about this topic.
*Image by Robert Fludd (16th Century)