A head-up: I am from an analytic background, and I have only read continental philosophy via second sources.
I am confused about what 'nothingness' mean in Sartre's ⟪Being and Nothingness⟫. Some authors explain that 'nothingness' is the denial of thinking of one's consciousness as a concrete entity with predefined essence. Consciousness is nothing more than the state of perceiving numerous individual stimulations; consciousness is nothingness. Sartre's 'nothingness' is an affirmation of vanishing the boundary between the subject(consciousness) and the object(the external world).
Other authors explain that 'nothingness' represents the unique ability of a human to perceive a lack of something in the world. Ordinary objects can only exist, and in that sense, it is a being-in-itself. Humans, on the other hand, can perceive a lack of something and can strive forward to solve its deficiency, and in that sense, it is a being-for-itself.
Which explanation is correct? Are both correct? Or is my understanding just wrong?