Full Idea
We reject the dualism of appearance and essence. The appearance does not hide the essence, it reveals it; it is the essence.
Gist of Idea
Appearances do not hide the essence; appearances are the essence
Source
Jean-Paul Sartre (Being and Nothingness [1943], p.4-5), quoted by Kevin Aho - Existentialism: an introduction 2 'Phenomenology'
Book Reference
Aho,Kevin: 'Existentialism: an introduction' [Polity 2014], p.28
A Reaction
This idea, expressed in the language of Hegel and Husserl, strikes me as the same as the analytic phenomenalism of Mill and Ayer. Hence I take it to be wrong.