protip Men and Women are different . But so are some men and women <| sep |> Look , I recognize that magic bends the laws of physics , but I don ' t agree that it exists outside them . If you cast Lightning Bolt on an enemy standing in the same pond as you , bad things can happen to you . Continual Flame specifies that it doesn ' t burn oxygen , but a magical fire lit by Prestidigitation does , and in a vacuum you wouldn ' t be able to light a candle with the spell . That ' s why adventurers who are level 20 and have 24 Constitution can still starve to death or suffer exhaustion , even if there are other things they do that are literally magic . That ' s why you still take bludgeoning damage from a fall . Basically , all of the laws of physics apply unless you ' ve got a specific magical reason that they don ' t . The illusion is seen even by people who the caster doesn ' t know are there , and by creatures with too low intelligences for the caster to manipulate . For that reason , we know that the caster isn ' t creating the illusion in people ' s heads . So clearly , if you ' re seeing it , photons are reaching your eyes carrying the information on the color spectrum that allows you to see them . The illusion is interacting with light . Would a mirror pick up the illusion ? If you were to invent a camera , would it ? These are objects that interact with light in order to work . Better , let ' s say there ' s the illusion of a person standing there in the darkness . If the illusion is standing between two people , and one of them holds a lantern to shine directly through the person , would a player who had failed his investigation check and believed the illusion to be there still see the light shining through him ? If so , then he must be seeing the illusion as transparent , despite his failure . If not , then the illusion IS blocking light , and therefore casts a shadow . There ' s no stipulation that it stops lantern light but not sunlight .