He was also a very effective literary critic. Man desires to be god. Existence is the process wherein a thing becomes what it will be , a dynamic development of essence from the ground of being. Such freedom, which is at the heart of human existence carries with it the burden of personal responsibility, because of this Sartre refers to it as a condemnation. Freedom is not freedom from , but is, freedom for .
Existence is a process of becoming that projects into the future.
One's existence is always a projection of possibilities to choose from. Thus freedom is always a projection of future possibilities for possible action. The lack of a pre-determined essence is the nothingness at the heart of being that drives the human to seek to define himself, such drive for the fulfillment of definition being the motor within existence. Man defines himself by the choices he has made. As there is no pre-determined essence every act of projection and choice is a defining and hence, essential, act.