This is what novice Illusionists are taught:
There are elements: acid, stone, fire, water, air, ice, and lightning. Creation also contains living matter (trees, beasts) and dead matter (soil, dead people). It also contains "radiative effusions".
LightLight is emitted from a source and travels in straight lines. It is reflected or absorbed by some substances. Some very clever experiments have proven that light is not emitted by the eye at all, as unlearned people claim. The light carries information about the things it has struck to the brain. For example, light from a torch that strikes a stone wall will investigate the stone, discover that it is grey and dark, and carry this information to the eye.
The sun, which is not made of fire but seems to be made of solid light, emits light. If you split this light (or, indeed, any other bright light) through a glass prism, you produce what is known as a spectrum of colours. Light from the sun is split into a range of colours, from red to violet. If you use an eight-sided prism, you also produce octarine.
However, this spectrum is merely the echo of true colours. True colours can only be produced through magic. They cannot be produced by matter for matter lends some of its nature to the light. True red is brighter and truer than any red dye, paint, or fabric. Each colour is unmistakable. Once seen, the colours of Creation are seen as tints, shades, and mixtures of the true colours. There are eight true colours, mixtures of which comprise all other colours observed in nature.
Red. Red contains heat as well, for it is known that the sun's light also heats Creation.
Violet. Also contains a kind of heat, although this heat is a harsh and blistering one, which blinds and scars.
Octarine. The colour of magic.
Octarine is instantly recognizable to anyone who has seen a spell cast. If you have not, close your eyes and rub them vigorously. The greenish-purple-pink-white colour produced is close to octarine. Alternatively, strike your head quite hard with a blunt object. The spots of dancing light produced are close to octarine as well.
The History of IllusionFor centuries, illusion magic languished in obscurity. Records from antiquity told of magicians summoning "phantasmal armies" or entire cities, but until the reign of King Althalbert, the most learned magicians in the land could produce nothing more than a few illusory birds or some feeble smoke. It was understood that brightly coloured clothed assisted the illusionist.
With the discovery of the lens, the prism, and the nature of light, illusion magic experienced a great revival. It became clear that Illusion spells were creatures of Light. To store and use these spells, the wizard's mind must be nourished with all colours of light. The use of rainbow-coloured gloves, proper training in the theory of light, and the abomination of the colour purple enabled Illusionists to rise from mere conjurors to the highest courts in the land.
Darkness is light's opposite. It is also radiative, but it seems to emerge naturally from all objects. The greatest Illusionist scholars work furiously to build a dark prism capable of spectrumating darkness. The task is made obscenely difficult by the nature of matter, no matter how carefully handled, to emit some trace amount of light, which inevitable spoils the experiment. Additionally, spellcasters naturally radiate faint rays of octarine.
This is what more advanced Illusionists are taught:
Life seems to also emit some intrinsic effusion, as does Un-life. Life effusions that strike Unlife are returned to the eye (or some other sensory organ, possibly the mind directly), as feelings of cold, dread, and horror. Unlife effusions that strike Life return and induce feelings of hatred and hunger.
Strong emotions are radiative. While the untrained can effuse hatred, love, or fear into Creation without any effect whatsoever, a trained mind can focus these emotions and emit them in dangerous or beneficial ways. There are tales of monks capable of calming a storm by radiating tranquility. There are shamans in the ice wastes who will hate an enemy to death - or at least, to very near death - for a fee. Courtly love is another form that proves this principle. A knight, far from his lady, produces rays of love which pass through the air and, owing to sympathetic resonance, strike and affect only his beloved.
Wisdom is also radiative. This is how universities and guilds operate. Sound is also radiative, as are kingship and holiness.
MirrorsAny fully reflective surface (that which allows differentiation of the shapes reflected, rather than just the reflection of light in general, which all objects possess) may not, in fact, be reflective. If the light received contains sufficient octarine, the mirror may reflect a parallel world instead of our own. These worlds have been studied very little due to the dangers they pose to our world. Most mirror-worlds are identical to ours in every respect. A wizard examining himself in the mirror might see a true reflection or an identical mirror-wizard, who is performing precisely the same actions and thinking precisely the same thoughts.
Some mirrors, especially those saturated with octarine light, show very different worlds. These worlds contain creatures unknown in Creation, air that corrodes metal, and other, stranger things.
Illusionists may use mirrors to assist their spells. For example, an illusionist can pull an illusory copy of a key from a parallel world. In truth, the key does not leave the mirror-world, but the spell allows the wizard to copy it precisely. Mirror copies, who are merely illusions assisted by the power of a mirror to reflect creation, can also be created. True mirror-passage is both rare and dangerous.
This is what Grand Illusionists ponder during sleepless nights:
Why do different effusions travel at different rates? Light and darkness both travel instantaneously. Sound travels considerably slower. Wisdom seems to travel very slowly indeed.
How can heat be transferred by contact as well as by light? How can heat be created by rubbing two objects of equal temperature together, if no light is produced?
What are Beholders, and what is their true purpose?
Illusions weigh next to nothing, but not quite nothing. Does light have a weight? Does darkness? Certainly, sound seems to have a weight, but what about hatred?
How intelligent are illusion spells? They seem to be able to imitate subtle details and even improvise.
If there are an infinity of mirror realms, are there also an infinity of Authorities and an infinity of Churches?