Being and Time describes his project in the following way: "our aim in the following treatise is to work out the question of the sense of "being" and to do so concretely." Heidegger claims that traditional ontology has prejudicially overlooked this question, dismissing it on the basis that being is the most universal and emptiest concept, that is indefinable or obvious. Instead Heidegger proposes to understand being itself, as distinguished from any specific entities (beings). "'Being' is not something like a being." Being, Heidegger claims, is "what determines beings as beings, that in terms of which beings are already understood." Heidegger is seeking
Being in itself 'Being in itself' to be at the same time the most vague and general concept possible to contemplate, but also the topic of greatest interest to him as a philosopher. In Sartrean existentialism, being-in-itself ("être-en-soi") is also contrasted with the being of persons, which he describes as a combination of, or vacillation or tension between, being-for-itself ("être-pour-soi") and being-for-others ("I'être-pour-autrui"). Being-in-itself refers to objects in the external world — a mode of existence that simply is. It is not conscious so it is neither active nor passive and harbors no potentiality for transcendence. This mode of being is relevant to