Why not deism?

[EgoDeath]

How so?

They assume, or believe there is some sort of god or creator, without evidence. That is called faith. Claiming you used reason to come to the conclusion that there's a god doesn't make it any more true. It doesn't even compare to having objective, verifiable evidence.

The universe itself is sufficient evidence of something not-universe. Or at least not this universe. As all arguments do, this rests on some assumptions, such as the principle of sufficient reason and a rejection of "brute fact" as a satisfactory explanation.

How does this relate to what I said?

For a deist, this is also true. This life is all there is. I'm not a deist, but I disagree that the stakes are not as high for me. They are higher, if you consider that eternal destiny rests on this one life. That doesn't even require faith: What if Nietzsche's eternal return is true? Then this life matters even more because it's not the only one and everything you do has far greater consequences.

That's not necessarily true. Plenty of deists believe in some kind of afterlife. They may not have the same idea of god as most theists, but they may still believe that consciousness exists in some way after the death of the brain. Which is another assumption based on no evidence.

I don't want to agree with "life is beautiful" but that's not true for everybody, either. It can be really not beautiful for some people, though perhaps there is no inherent beauty in simply being.

Sure there is. Life and nature are fascinating. Even people in the most terrible of circumstances can, and often do, find happiness and wonder in life. That's not to say there isn't suffering in life as well. No one's claiming it's all rainbows, grapes being fed to you and endless orgasms. Life has it's ups and downs. But it's beautiful to me. And that's enough for me.