Like many edgy teenagers, I once embraced nihilism—the belief that nothing matters, that existence is fundamentally meaningless. I could write a book on how strongly I subscribed to this area of thought, but that’s not the point of this post; you’ll have to trust that the following comes from someone who climbed out of the pit: Everything matters. And that’s even scarier. I still don’t believe in broad concepts like “meaning” or “fulfillment”. I believe in biological reactio...