Some philosophers deny that the concept of "being" has any meaning at all, since we only define an object's existence by its relation to other objects, and actions it undertakes. The term "I am" has no meaning by itself; it must have an action or relation appended to it. This in turn has led to the thought that "being" and nothingness are closely related, developed in existential philosophy.
Existentialist philosophers such as Sartre, as well as continental philosophers such as Hegel and Heidegger have also written extensively on the concept of being. Hegel distinguishes between the being of objects (being in itself) and the being of people (Geist). Hegel, however, did not think there was much hope for delineating a "meaning" of being, because being stripped of all predicates is simply nothing.
Heidegger, in his quest to re-pose the original pre-Socratic questions of Being (of why is there something rather than nothing), wondered at how to meaningfully ask the question of the meaning of being, since it is both the greatest, as it includes everything that is, and the least, since no particular thing can be said of it. He distinguishes between different modes of beings: a privative mode is present-at-hand, whereas beings in a fuller sense are described as ready-to-hand. The one who asks the question of Being is described as Da-sein ("there/here-being") or being-in-the-world. Sartre, popularly understood as misreading Heidegger (an understanding supported by Heidegger's essay "Letter on Humanism" which responds to Sartre's famous address, "Existentialism is a Humanism"), employs modes of being in an attempt to ground his concept of freedom ontologically by distinguishing between being-in-itself and being-for-itself.
As far as we can discern, the sole purpose of human existence is to kindle a light of meaning in the darkness of mere being. - Carl Jung
Under the heading ‘Individuality in Thought and Desire’, Karl Marx, (German Ideology 1845), says:
"It depends not on consciousness, but on being; not on thought, but on life; it depends on the individual's empirical development and manifestation of life, which in turn depends on the conditions existing in the world."