Existentialism is an attempted solution to the problem of nihilism - the feeling that life is meaningless and there is no point, perhaps because you feel that all your efforts, relationships and projects will be rendered futile by the fact that you will die and ultimately be forgotten, because you feel insignificant in the face of the enormity of the universe, or that the world seems unfair given the unjust pain, suffering and death - the feeling might be akin to depression or angst or despair or anxiety or even panic. Camus says that this is the feeling of absurdity, which arises from The Absurd: the dissonance between how I want the world to be and how the world really is. Schopenhauer seemed depressed and miserable for much of his life, believing that life was ultimately pointless and miserable - he wasn't persuaded by people telling him to put on a happy face!

    Nietzsche – ‘The Madman’, from The Gay Science

    Edwin Muir – ‘The Child Dying’

    Unfriendly friendly universe,
    I pack your stars into my purse,
    And bid you so farewell.
    That I can leave you, quite go out,
    Go out, go out beyond all doubt,
    My father says, is the miracle.

    You are so great, and I so small:
    I am nothing, you are all:
    Being nothing, I can take this way.
    Oh I need neither rise nor fall,
    For when I do not move at all
    I shall be out of all your day.

    It's said some memory will remain
    In the other place, grass in the rain,
    Light on the land, sun on the sea,
    A flitting grace, a phantom face,
    But the world is out. There is not place
    Where it and its ghost can ever be.

    Father, father, I dread this air
    Blown from the far side of despair
    The cold cold corner. What house, what hold,
    What hand is there? I look and see
    Nothing-filled eternity,
    And the great round world grows weak and old.

    Hold my hand, oh hold it fast-
    I am changing! - until at last
    My hand in yours no more will change,
    Though yours change on. You here, I there,
    So hand in hand, twin-leafed despair -
    I did not know death was so strange.

    Nietzsche's allegory/parable/story/metaphor of "The Madman" and Muir's poem push us toward a feeling of despair, and nihilism as a philosophical perspective:

    you realise the significance of no God (that you can’t go on as before)
    that there is no (objective) grounding for ethics; no purpose; no meaning; no point


    [nihilists are not satisfied by existentialist responses that advocate a subjective purpose while acknowledging there is no objective purpose - for the nihilist, just as for e.g. a (realist) Christian, an objective purpose is the only type of purpose that could exist - they might argue that the concept of a "subjective purpose" is inherently contradictory]