Hmmm...how about this, now before you start going all science on my ***, remember this game has MAGIC! Now what if you weren't actually invisible, but it were indeed just an illusion on all beings alive, containing lifeforce, thus your opacity doesn't change, but a trick on the mind, causing that specific point to be veiled, a scientific answer, could be that when 'veiled' you give out a signal or frequency which forces the source to be 'invisible' when registered with the person looking's brain, thinking mechanism etc.

Two words. Invisible Woman.

From what I've seen, Illusion involves both manipulating light (like with Light and Invisibility, which have outward effects to anyone who can see) but also affecting an individual's mind and senses, such as Night-Eye and Blind, affecting one's eyes, Calm/Frenzy/Demoralize/Rally/Command, which affect the mind, and Paralysis, which affects the motor system.

Maybe its like an elemental shield of bending light. Anything in that sheild will be shielded from ligth, or soemthing :shrug:

I don't think we can say that light is bent, since that is alteration, what we can say is that a trick on the mind is performed, see my post before for more details.

I believe the concept of "Alteration" can also apply to certain spells in the School of Destruction and the School of Restoration. However, it appears that not all that is "alteration" is covered under the School of Alteration.

Well i take illusion as how you defined it CP, something which affects the senses, mind or motor system, and as far as i can tell invisibility is illusion.

I like to think that being an illusion spell, you're preventing other people's eyes from seeing you rather than doing something to yourself.

A good thing to remember is that the different 'schools' of magicka are just general labels created by the Mages Guild or some such entity. Being in a certain school doesn't necessarily govern the properties of the spell - spells (and schools) have been shifted, disappeared and changed in the past.

Ir definately is magic, so really, it can work however Bethesda says it works. And Bethesda says it makes others unable to see you, but you can still see them. How this effect is achieved I don't think we know. But one should also note that illusion also includes light, so it could be that it works by manipulating light somehow. Of course, one never knows with magic, things like making sense according to modern science or for that matter, real world logic are not a requirement.