When Friedrich Nietzsche, who had fully absorbed the implications of Darwinian evolution, announced that “God is dead,” he was not merely addressing orthodox religion. He was telling moderns that there was no meaning or direction to be found in nature or history at all. He was telling them that Georg W. F. Hegel, Auguste Comte, Herbert Spencer, and Karl Marx were victims of the residual influence of the idea of Providence, that their visions of an unfolding historical necessity were delusions. The thing that really mattered in the long run about Charles Darwin wasn’t the impact of “we are descended from monkeys” on reactionaries; it was the impact of “we are a meaningless accident” on progressives. Think of the tone in Max Weber, Sigmund Freud, and Theodor Adorno, the stoic willingness to face up to irredeemable loss and make the best of it. Think of the ferocious absolutism of twentieth century totalitarian regimes. These represent opposing but characteristic moods, and both were responses to a condition of utter abandonment and a consequent shift of the burden of responsibility for human practices to human beings.
This paragraph isn't really representative of the larger essay; I just thought it was an elegant encapsulation of all the light and heat surrounding that famous phrase. Still, calling humanity a "meaningless accident" seems a bit like an overcorrection — an accident typically implies a regrettable deviation from purpose. If human existence, with all its myriad wonders and joys, is an accident, then what must the implied purpose be? It could only be pointlessness, nothingness, entropy. As I've said often, nihilism is a last-gasp attempt to find universal meaning by inverting the concept when all other options have failed. If meaning and value can't be grounded in something eternal, then nothing ever has any meaning at all. (It's the same logical error that says, if you can't get an absolute perfect score on a test, fuck it, might as well turn in a blank page and get a zero.) God's brittle skeleton gets propped up on the throne out of desperation.
It seems just as accurate, without being quite so bitterly spiteful, to say that humans aren't guaranteed anything. We weren't guaranteed to come into existence as a species. We're not guaranteed to keep molding our world to our satisfaction. We're not guaranteed to figure out the answers to any questions or problems we can conceive of. And we're not guaranteed to exist indefinitely. Nonetheless, we're here, and what we do matters to us. Let that be good enough.