Quote from : Irrational Man: A Study in Existential Philosophy Book

Positivist man is a curious creature who dwells in the tiny island of light composed of what he finds scientifically "meaningful," while the whole surrounding area in which ordinary men live from day to day and have their dealings with other men is consigned to the outer darkness of the "meaningless." Positivism has simply accepted the fractured being of modern man and erected a philosophy to intensify it. Existentialism, whether successfully or not, has attempted instead to gather all the elements of human reality into a total picture of man. Positivist man and Existentialist man are no doubt offspring of the same parent epoch, but, somewhat as Cain and Abel were, the brothers are divided unalterably by temperament and the initial choice they make of their own being.