Phenomenology is the study of appearance as such. It is a branch of both Ontology and Epistemology, since appearing is being known. By an ÔappearanceÕ is meant any existent which impinges on consciousness, anything cognized, irrespective of any judgment as to whether it be ÔrealÕ or Ôillusory.Õ The evaluation of a particular appearance as a reality or an illusion is a complex process, involving inductive and deductive logical principles and activities. Opinion has to earn the status of strict knowledge.