Heidegger put forward that the relationship between man and the world is not to know and transform the world at first, but "man exists in the world", that is to say, man is the existence in the world first. So, what kind of existence is man? Heidegger said that man is lonely; Heidegger deliberately explained it with "fear of death". When we are afraid of death, we will deeply realize that our existence is our own business, and no one can replace it. In this sense, everyone is "free".

From here, Sartre went on to say that how people exist should be the result of their own choice, that is, people first exist in the world, and then people freely choose their own behavior, and human behavior determines the essence of people, so Sartre said that "existence precedes essence."

In this way, human nature is the result of free choice, or it should be the result of free choice. But Sartre believes that we are often involuntarily in reality, and this obstacle is the eyes of "others". The eyes of others are terrible. They unscrupulously interfered with my choice, making me hesitate and even forced to make a choice I don't want (I think you should feel the same way when you contact your life experience). The protagonist in Sartre's play Intermittent Break is such a situation, so he sighed at the end of the whole play: "Everyone else is hell!" " "