existentialism "A 20th-century movement in philosophy…All existentialists are concerned with ontology, the study of being. The point of departure is human consciousness and mental processes. In contrast to most previous philosophical systems, which maintain that an a priori essence precedes or transcends the individual existence of people or of objects, the existentialists conclude that existence precedes essence. The significance of this for human beings is that the concept that one has an essential self is shown to be an illusion. A man's self is nothing except what he has become; at any given moment, it is the sum of the life he has shaped until then. The 'nothing' he begins with is thus the source of man's freedom, for at each moment it is man's will that can choose how to act or not to act. However, each such decision affects the future doubly: a man is or should be responsible for the consequences of his actions; and each action necessarily excludes the other potential actions for that moment, and their consequences, and thus at least partially limits the potentialities for future actions. "By what standards, then, should a person make decisions? The mind cannot discern any meaning for this existence in the universe; when a person abandons his illusions, he finds himself horrified by the absurdity of the human condition…a person must create a human morality in the absence of any known predetermined absolute values"