"Being can only generate being and, if man is embedded in this generational process, he will only emerge from being. If he is to be able to question this process, that is to say, to question it, he must be able to hold it under his sight as a whole, that is, to put himself outside of it and thereby weaken the structure of being it. However, it is not given to the "human reality" to destroy, even temporarily, the mass of being that is laid in front of it. What it can change is its relationship with that being. For it, putting out of the circuit a particular existing, is to put itself out of the loop in relation to that existing. In this case it escapes from him, it is out of reach, it cannot act on it, it has withdrawn beyond a nothingness. This possibility for human reality to secrete a nothingness that isolates it, Descartes, after the Stoicians, gave him a name: it is freedom."J.-P. Sartre.