Existentialists argue that humans are fundamentally free beings who are not bound by any predetermined essence or nature. This freedom is both a source of anxiety and a source of possibility.

Existentialists argue that humans are not simply observers of the world, but rather that they are active participants who shape their world through their actions and choices.

Existentialists argue that humans should strive to live in accordance with their true selves, rather than conforming to social norms or expectations.

Existentialists argue that humans are responsible for creating their own meaning and purpose in life. There is no inherent meaning or purpose to life, but humans can create their own meaning through their actions and choices.

Albert Camus is known for his concept of "the absurd", which refers to the inherent contradiction between the human desire for meaning and the meaninglessness of the universe.

Martin Heidegger is known for his concept of "being-towards-death", which refers to the fact that humans are always aware of their own mortality and that this awareness shapes their existence.

Søren Kierkegaard is known for his concept of "the leap of faith", which refers to the decision to embrace faith in God despite the lack of rational evidence.

Jean-Paul Sartre is known for his concept of "bad faith", which refers to the act of denying one's own freedom and responsibility.

Viktor Frankl is known for his concept of "the existential vacuum", which refers to the feeling of emptiness and meaninglessness that can result from a lack of purpose in life.

Friedrich Nietzsche is known for his concept of "the will to power", which refers to the fundamental drive that motivates all human behavior.

Friedrich Nietzsche is known for his concept of "the eternal recurrence", which refers to the idea that all events in the universe will repeat themselves infinitely.

Friedrich Nietzsche is known for his concept of "the Übermensch", which refers to the ideal human being who has overcome traditional morality and values.

Friedrich Nietzsche is known for his concept of "the death of God", which refers to the idea that traditional religious beliefs are no longer tenable in the modern world.

José Ortega y Gasset is known for his concept of "the revolt of the masses", which refers to the rise of a new social class that is characterized by its lack of culture and its desire for power.

Søren Kierkegaard is known for his concept of "the existential crisis", which refers to the crisis of faith and meaning that can occur when a person becomes aware of their own mortality and freedom.