"To view a human being as an isolated existent who is cast into an alien universe; to conceive the human world as possessing no inherent truth, value, or meaning; and to represent human life – in its fruitless search for purpose and significance, as it moves from the nothingness whence it came toward the nothingness where it must end – as an existence which is both anguished and absurd.”
In short: life itself is too incomprehensible and therefore seen as a joke or as absurd