Esoterica - Hidden Lore
Refining, Divining, Invoking and Altering
Behind all visible phenomena is the aether. All things, animate and inanimate are infused with this as well as greater and lesser portions of the other elements (air, earth, fire and water), in accordance with their names (numina). Such is the nature of things, and all enterprise is confined by the facts arising from this underlying nature. All arts, crafts and sciences deal on some level with manipulating the elemental and spiritual nature of things.
However, some have a deeper understanding of this nature, they know what most people know not, they have esoteric knowledge. This gives them the power to interact with the world on a more profound level than most mortals.
Refining - Alchemy and Herbary
Two main work on the aether: alchemy and herbary.
By knowing the elemental composition of items, and the interrelations between these elements, one may discern and even concentrate the magic lying within all things. This is the basis of alchemy and herbary. Unlike sorcery, these arts are seen as good and natural, even respectable crafts.
Alchemy studies the inherent qualities of a variety of substances, combining and refining them. Herbary is the study of herbs and their applications.
Neither craft requires a sensitivity to the aether - alchemy and herbary may be learned by anyone. However, those who comprehend the aether are much advantaged in the study of these disciplines.
Divination - Astrologers , Augurs and Oracles
By understanding the interrelations of the world, the movements of spirits and essences, one can try to see the hidden influences in the world, and thereby predict the future of enterprises and people.
The predictive arts seek not to control, but to predict and to understand. Any manipulation of the world is indirect, a man who knows his fortune may hope to improve it.
Some people have a talent for divination, but most forms of divination can be learned by most people. The sole exception is being an oracle.
Clergymen often try to establish a monopoly on some or all forms of divination.
"Divination" in the form of knowing and following various portents is also practiced by just about everybody.
Astrology
Astrology is the art of studying the heavenly bodies and foretelling things to come by their movements. Unlike most other forms of prediction, astrology is passive - the heavens cannot be subjected to manipulation, and predictable. Hence, intuition is far less important in astrology than in other forms of divination, and "book learning" is far more so.
Most sects agree that the practice of astrology is permissible for layfolk
Augury
Most forms of divination can be summed up as highly intuitive interpretation of unpredictable phenomena. Augury combines knowledge and imagination into prediction.
Many augurs are members of the clergy.
The media of augury are quite varied, they include reading the stars like an astrologer (astromancy), the use of tarot cards (cartomancy) and many other methods. Haruspication, the reading of eggs and entrails is considered the most difficult and the most reliable - divination by haruspication is most often considered a sacral monopoly.
Each form of augury is learned as a separate skill.
The mighty and the wealthy always try to keep an augur as a retainer, while the middle class tend to consult them before making very important decisions.
Oracles
Oracles are simultaneously the most potent and the least convenient of diviners, as these things often go.
Oracles have a gift, bestowed by nature at birth, at will by the gods, or (very rarely) acquired through a deep understanding of the nature of the world.
Oracles use their gift to read omens out of everyday things. They may not, however, pose questions.
Invocation - Calling the Spirits
Rather than merely observing and utilizing the natural laws of the world, the practice of invocation calls upon spirits to alter these laws and twist chance. Invocation forms a middle ground between the other esoteric arts and sorcery.
Sorcery - Commanding the Aether
The aether, unlike the other elements, is inferred, rather than seen.
Some, however, are aware. They can sense the aether, its might rolls and swirls. Some can even influence its movement of the aether. The latter are sorcerers.
Sorcerers can build and break, heal and harm, create and annihilate, summon and abjure. Nothing is denied to a sorcerer with a strong enough will and the right invocation.
But the perils of magic use are manifold. A miscast spell often proves a disaster. When magic goes out of control, chaos reigns the ground, and its taint takes many forms.
A spell may simply go awry, striking an unintended target, or it may change nature entirely. Bystanders may be bathed in strange energies, leaving them altered for life, or for a heartbeat. Reality may collapse into shapeless apeiron, or holes may be torn through it, into other realities.
All sorcerers are somewhat neurotic and arrogant. But many are worse, being outright mad. Other go mad gradually, worn down by their harsh craft.
The truth of magic, as known by a sorcerer.