In Heidegger's philosophy being in itself is contrasted with the Being of persons, which he calls Dasein. Dasein is Being that is aware of and interested in its own Being. Dasein is, by its nature, invested in social interaction and society. The argument for this claim draws heavily on Hegel'sPhenomenology of Spirit.
Being in itself can justifiably be used as a means to an end - that is, things can be used as tools - whereas Dasein is subject to moral laws.
There is some speculation that Heidegger's anti-Semitism stemmed from the fact that he did not consider Jews to be fully Dasein because they segregated themselves from society.
Being-in-itself for Sartre
In Sartrean existentialism, being-in-itself is also contrasted with the being of persons, which he describes as a combination of, or vascillation or tension between, being-for-itself and being-for-others.
One of the problems of human existence for Sartre is the desire to attain being-in-itself, which he describes as the desire to be God - this is a longing for full control over one's destiny and for absolute identity, only attainable by achieving full control over the destiny of all existence. The desire to be God is one of the ways people fall into bad faith.
Being with a capital 'B', on the other hand, is often used in philosophy to refer to divine Being, God, or ultimate reality.
To Aristotle, only spirits and God are independent of matter, and thus these entities are purely "substance" or "being." This is the origin of the phrase "One in substance with the Father" or modernly "One in being with the Father" in the Catholic Nicene Creed.
This in turn has led to the thought that "being" and nothingness are closely related, developed in existential philosophy.
In Heidegger's philosophy being in itself is contrasted with the Being of persons, which he calls Dasein.
Being in itself can justifiably be used as a means to an end - that is, things can be used as tools - whereas Dasein is subject to moral laws.
In Sartrean existentialism, being-in-itself is also contrasted with the being of persons, which he describes as a combination of, or vascillation or tension between, being-for-itself and being-for-others.