What are the key concepts of existentialism in philosophy?

Existentialism is a philosophical movement that emphasizes individual existence, freedom and choice. It originated in the 19th and 20th centuries, and it is still an important movement today. The key concepts of existentialism are:

• Existence precedes essence: The idea that there is no pre-existing meaning or purpose to life, and that individuals must create their own meaning through their actions and choices.
• Authenticity: The idea that individuals must take responsibility for their own lives and choices, and that they should not conform to society's expectations.
• Freedom: The belief that individuals have the freedom to choose their own path in life, and that they should embrace this freedom rather than try to avoid it.
• Anxiety: The feeling of anxiety that arises from the realization that individuals must create their own meaning in life, and that there is no pre-existing purpose to their existence.
• Death: The realization that death is an inevitable part of life, and that individuals must confront the fact that they will one day die.

Existentialism has had a significant impact on philosophy, literature, and the arts. Some of the most well-known existentialist philosophers include Jean-Paul Sartre, Friedrich Nietzsche, and Martin Heidegger.