Our existential angst seems to be the curse of our intelligence. The theories of existentialism, nihilism and absurdism explore the problem of human existence; and converge on the idea that life has no inherent meaning. All three philosophies approach the problem differently.
The three theories questioning the meaning of life.
Nietzsche's Nihilism
Sartre's Existentialism
Camus' Absurdism
In conclusion