Being, the First Division of Hegel's Logic, in terms of the theory of cognition, is the first stage in the process by which people arrive at knowledge of the world.
In the study of philosophy, Being always denotes the "historical context" - the whole social, technical, cultural, political context in which the philosophy arises, and its position within that context.
When we say that the Logic is also a theory of the development of science and culture on the historical scale, we should make the proviso that it should not be used (as it tended to be by Hegel) as a straitjacket into which the real history of thought must be squeezed. Nevertheless, this aspect of the Logic brings out in especially clear form that each stage of the Logic is a self-sufficient and valid world-outlook ["a systematic whole of thought-terms", Shorter Logic §86n]. The Logic works out the basis of each outlook, its inner contradiction and where it leads to. Thus, the Logic also provides an approach to understanding different personalities, different viewpoints and political or social tendencies and methods which co-exist within a given situation.
In the history of philosophy the different stages of the logical idea assume the shape of successive systems, each based on a particular definition of the Absolute. As the logical Idea is seen to unfold itself in a process from the abstract to the concrete, so in the history of philosophy the earliest systems are the most abstract, and thus at the same time the poorest. The relation too of the earlier to the later systems of philosophy is much like the relation of the corresponding stages of the logical Idea: in other words, the earlier are preserved in the later: but subordinated and submerged. [Shorter Logic §86n].
Being - Notion - Idea
The philosophy of Being is first of all "awareness". In this century it is the point of view expressed by, for example, Krishnamurti, and is strongly present in the martial arts; among the popular applied psychologists "active listening" closely expresses the standpoint of Being. It is also called seriality - "one damn thing after another".
Pure Being is the world an instant before you see it, it is the world through the eyes of a new born baby. Like the Zen teaching that demands of the devotee absolute awareness, absolute "thoughtlessness", it is, for consciousness, an unattainable moment - even though it is equally the beginning of all consciousness!
In the words of Jean Piaget:
"at first the universe consists in mobile and plastic perceptual images centred about personal activity. But it itself-evident that to the extent that this activity is undifferentiated from the things it constantly assimilates to itself, it remains unaware of its own subjectivity; the external world therefore begins by being confused with the sensations of a self unaware of itself, before the two factors become detached from one another and are organised correlatively" [The Construction of Reality in the Child, Conclusion]
As Hegel says, there is absolutely nothing you can say about being without in doing so "further determining" it, without putting in place of pure Being some particular, some finite, an example. Being is absolutely featureless, or rather does not yet show any feature. Thus, as Hegel says "Being is Nothing" [§86n], , a discovery which impels us forward, to the necessity of further determination, to recognise things, to discover what lies behind Being.
Such reflection is only possible because we are natural human beings, with material brains, sense organs and material needs founded in Nature, in other words because we are part of Being, products of Nature. Further, every act of reflection or recognition, every determination, pre-supposes that we already have in our heads some concept, or Notion. These concepts (Notions) are social products acquired over millennia and passed on to individuals through society. In other words, Being becomes only because we are also not of the world, because we have separated ourselves from the world and are its Other.
The Notion is the concept we have of the world - the Other of the world. It is abstract in the sense that each Notion corresponds to but one aspect of the world, just as each moment of Being, each event, passing impression or statistic, is abstract, meaningless and disconnected.
However, the Notion, as a summing up of millennia of human practice, in comparison to the way Being comes before us as "one damn thing after another", is rich and concrete.