An illusion could be done with:
an elaborate P14@2 Alter Appearance applied to the air itself.
Could the appearance be perceived even if there are no light?
I would say with this specific type of illusion the answer is no. The nearest you could get would be to create an image so highly reflective that the minimal amount of light striking it was reflected and/or focused in the desired direction, and that would probably be difficult enough to be penalized. You can make "mirrors", but you can't make "lightbulbs".
If someone try to make a firefly using this technique in the night, could anyone see it if there are no light or do the other person perceive this air as a firefly even if there is no light?
Since people can see only reflected or radiated energy, and by definition this cannot radiate energy, there must be energy to reflect--light would be required.
If someone give the air the appearance of light, can this air light the surrounding or only this air would appear bright but not affecting its surrounding?
If someone creates light, it will act in accordance with the rules imposed by its creation, within the limitations of physics; if someone causes someone else to perceive light, it will behave as the mental suggestion requires. If you create reflectors as if they were light sources (e.g., the moon), they would reflect such light as strikes them, and that light would behave appropriately according to the laws of physics.
Can something not real be affected by something else that is not real (or specifically can illusion affect delusion)?
There are too many specific cases for this to be fully explained. Here are some examples:
- If you are delusional such that you believe there is a visible object, and you create something "illusory" that will pass behind or through the object to test its reality, your mind will not permit you to see the illusion to the degree that it interferes with the delusion. Lights will vanish behind it, or bounce off it, or be absorbed by it and reappear on the other side. The delusion will act as if it is real, and the illusion will be forced to accept that.
- If someone else is delusional and you force their mind to see something "inconsistent" with the delusion, they will attempt to rectify the disparate images such that both can exist.
- If someone is being forced to see something that is not there by an outside hand and you attempt to force them to see something different, it becomes a battle of skill checks (relative success) to see to what degree one or the other illusion is perceived by the target individual, depending in part on how incompatible they are. If, for example, one practitioner is trying to force the target to see light and the other to see darkness, an intermediate light level might be achieved. If one is attempting to force the vision of a solid object and the other to remove that vision, the object might appear less than substantial. However, it might be that one side wins completely, particularly if the disparity in rolls is high enough.
Other cases could be presented, but this should give a good starting point.
Can delusion resist the suggestion of an illusion if that person think the delusion could do so and alternatively the delusion could not resist if that person think the suggestion of an illusion will be effective to the delusion?
I think this is covered in the previous examples. It largely depends on the natures of the delusion and the illusion and who is behind each. A delusional person cannot disprove his delusion to himself by any means, since whatever he does will confirm the delusion. Such a person might be forced to see inconsistent realities by an outside agent, but not by this skill. This skill would change the appearance of reality, but since the delusion is in the mind of the beholder, he is already seeing something other than what is there, and the appearance of reality is irrelevant to the perception.
--M. J. Young
