That which is not real is an illusion. What is an illusion judged by, common sense, the amount of pain or pleasure involved, whether or not it can be touched? Illusions are real in only one place, the mind. You believe what you want to believe and hear what you want to hear. Illusions tend to reveal themselves only after they loose their luster. Surrounded by desert the hummingbirds want the flowers they see to be real, only one bird is not so sure. Past illusions litter the ground with little regard from the birds that are willing to believe the bright lure once more.