Being-in-itself
The idea of being-in-itself is referred to often in the text. Essentially, this is something that unchanging, unconscious, and solid. This includes the everyday objects we see around us, that do not have consciousness.
Being-for-itself
Being-for-itself is another concept Sartre refers to often. This is something that is aware of itself and conscious, but is also always changing so can never have a concrete state. As such, a human would be in the being-for-itself category.
Existentialism
The idea of existentialism is often symbolized by an idea of meaninglessness or nothingness. This is something that Sartre partly agrees with, but also suggests that from this humans are able to shape their own lives.
Observation
Observation from others symbolizes the moment we are aware of ourselves, according to Sartre. As such, this is a key aspect of his discussion about consciousness and self-awareness.
Freedom
Sartre argues that freedom is one of the best aspects of being human. However, this positive thing requires a sacrifice, which is the curse of consciousness and responsibility.
