Essences belong to the concept of being-in-itself. These beings—simple forms of existence distinct from humanity—have a clear purpose and innate is-ness that defines them. Being-for-itself stands in stark contrast to being-in-itself. Sartre proposes that consciousness “is characterized, on the contrary, by its decompression of being” (123). This means that consciousness is about unity rather than dualities. In the Introduction, Sartre reveals how dualities present a limited understanding of consciousness. For example, consciousness is not limited to the internal; it is the culmination of the external and the internal. Therefore, Sartre proposes that consciousness encompasses both belief and the consciousness of belief. Being is all-encompassing. This idea relates to Part I, Chapter 1’s description of nothingness. Many would view nothingness as the counterpart to being, but Sartre argues that it is synonymous. Both being and nothingness are existence; they are one. In this chapter, Sartre argues that the existence of the being-for-itself is the unification of many different dualities.

Sartre faces head-on the contradictory nature of consciousness. He begins by outlining what being-for-itself is not. Consciousness is neither presence nor is it immediate. By focusing on negation, he reveals how important this concept is to the understanding of consciousness.