If we are all just for our own sake, what conclusion could we ever come to? What are we then, how--what makes us so great that even our mere existance is the explanation of our presence; each some sort of unique gift to the universe? I, you, we are each a bundle of cells, hormones, arguably a soul, but definitely atoms in space-- space, which is both infinitely large & infinitely small.
Instead of right or wrong, we are diminished to foolish little snowflakes, all dumbly in our own way, "human." "Art for art's sake," we are all paintings on the mantle: abstract & upside-down, but nobody can tell the difference.