Atheism

The exact same thing as nihilism.

both deny any true reason to persevere.

both say that we're a little inferior piece of stardust without a purpose other than eat, poop, and reproduce.

Both are often associated with hedonism and egoism.

Neither offer any reason to live.

"Welp, I'm an atheist. I believe in Atheism. I'm nothing but a little insignificant spec. I might as well kill myself and it won't really matter, other than the fact that other little insignificant specs will be sad for a little while. but why does it matter?!"