Existentialism is a philosophical theory that emerged in the XIX century, and that remained very popular until the first half of the XX century, especially during World War II, a period when many of the main ideas associated to existentialism arose and were profoundly debated.
This doctrine, as the name indicates, is focused on the analysis of the existence itself, claiming that this is the basis for all human experience, that is only later individualized through personal experiences and knowledges. This way, there is an idea of continuous evolution throughout life linked to this theory, given the fact that existence comes before essence, being this last one a later individual construction
Even though the term “existentialism” was only created in the 40’s of the XX century be the French philosopher Gabriel Marcel, the origins of this current of thought go way back, and it’s commonly agreed that the Danish Søren Kierkegaard was the first philosopher to develop theories that are seen as existentialist. Kierkegaard tried to understand what the “I” is, and for that he focused mainly on the human liberty of choice, as opposed to more determinist theories, and in the unique and intriguing capacity of the human being to develop abstract ideas. This line of thought was afterwards followed and developed by many other philosophers, which helped spread existentialism through Europe, among which the French Albert Camus and Jean-Paul Sartre played a determinant role.
According to existentialism, first the individual exists in the world, and only then he defines himself, which gives to the human being a strength and a weakness at the same time: each person is responsible for himself, for his morals, for his choices and actions and for, basically, what he is, for his essence; however, with the total freedom of the definition of the individual essence, comes the anguish and the weight of being responsible for the definition of the individual path to follow. For existentialists, there is no moral a priori, it is a construction of each one, given the fact that liberty also brings responsibility, and there isn’t also any meaning for anything in the world, except the one each one attributes to each thing, being meaning also a construction and not an inherent quality of things. The existentialist theory defends that all decisions are made based on the subjective meaning each individual attributes to a given thing or situation, and not on a rational general thought that is innate.
Given this, it is understandable that one of the major critics to existentialism was always the fact that it is an extremely individualist theory, and all its responses regarding human existence are centered on the individual, not giving any credited to social constructions.
Each individual, his essence, is a construction made by himself, according to existentialism, which gives the human being a power and a sense of responsibility that are not often found in the philosophical field, making this theory on of the most important ones in Philosophy, and that until this day is still adopted, studied and developed by many authors.