from
The Collaborative International Dictionary of English v.0.48
existentialism \ex`is*ten"tial*ism\, n. (Philosophy)
a philosophical theory or attitude having various
interpretations, generally emphasising the existence of the
individual as a unique agent with free will and
responsibility for his or her own acts, though living in a
universe devoid of any certain knowledge of right and wrong;
from one's plight as a free agent with uncertain guidelines
may arise feelings of anguish. Existentialism is concerned
more with concrete existence rather than abstract theories of
essences; is contrasted with {rationalism} and {empiricism};
and is associated with Kierkegaard, Heidegger and Sartre, as
well as others.
[PJC]