I don't.<quoted text>
How do you know the universe always existed?
But no evidence points to a creator or a cause.
As far as I can tell, all of the evidence we have so far indicates that there is no need for a god.
I'm able to say to myself "I don't know" without needing to fill in the gap with "therefore, god".
We may understand the singularity someday, and we may not.
In the meantime, that's about the only missing piece of the puzzle.
If there's one thing I've learned is that if there is a god, it's nearly completely unreliable and definitely not worth counting on.
I've only got myself for that.