But what does Heidegger mean by “being” ? The question is difficult
and controversial. To get a clear and complete concept of being, we would
need to have completed the project of Being and Time itself. However, as
Heidegger emphasizes from the outset, we already have an implicit, vague
understanding of being that we can work with — as he does in his book. The
following remarks, then, are inexact elucidations of Heidegger’s usage of
the word Sein, not strict definitions.
First, Heidegger often uses “being” as one might use “essence” or
“nature” : for instance, to examine “the kind of Being which belongs to
the living as such” is to establish what defines something as alive (BT 10).
Heidegger calls this “what-being” (BP 77 – 121).
“Being” also has what is often called an existential sense, or “that-being.”
An entity, something that is (or, in common parlance, exists), is something
instead of nothing. “Being lies in the fact that something is [as well as] its
Being as it is” (BT 7).
Furthermore, Heidegger emphasizes that being is not an entity. It “is”
not, but it is given to Dasein as the entity who understands being (BT 183).
Being is essentially related to Dasein’s understanding; it is that in terms of
which Dasein understands entities as entities (BT 6).
These various usages cohere, as long as we are willing to challenge some
standard distinctions such as the split between what-being and that-being.
What it means for something to “ exist ” (that-being) may depend on what
sort of entity it is (what-being), and vice versa. If we keep what-being and
that-being utterly separate, we easily end up assuming that “existence” has
one and the same sense for all kinds of entities. That is precisely the unquestioned,
reductive understanding of being that Heidegger found pernicious