A contrast heralded in the phenomenology of Husserl and Heidegger, and central to Sartre's work Being and Nothingness. Being for-itself (pour-soi) is the mode of existence of consciousness, consisting in its own activity and purposive nature; being in-itself (en-soi) is the self-sufficient, lumpy, contingent being of ordinary things. The contrast bears some affinity to Kant's distinction between the perspective of agency or freedom and that of awareness of the ordinary phenomenal world.