Story about a wealthy atheist seeking to (not) locate God

I ran across a short story somewhere around 2005-ish, and now I can’t seem to find it again.

The main character is a very wealthy person who firmly believes that God does not exist, and is out to prove it by process of elimination: by demonstrating conclusively that God is not located in any place. Much like Bruce Wayne or Tony Stark, our protagonist is someone with vast resources, which he puts to work in service to the cause, developing ever-greater technologies to scour the universe and rule out the existence of God by process of elimination, eventually becoming capable of monitoring the entirety of the universe simultaneously, to rule out God moving around in order to hide from his search.

Despite this obsession, he is a basically good person, one who believes that there is no need for God to establish good morality in society. He does his best to encourage positive change in the world, both at the individual and the societal level, and ends up becoming better-known for his philanthropy and his self-help writings than for anything else he’s done.

When his search eventually proves successful by proving completely and ultimately fruitless, one nagging doubt remains: a being as powerful as God is said to be might be able to evade his search by escaping along the fourth dimension. So he bends his resources to inventing time travel, which is ultimately successful, and begins to search for God as far back as The Beginning, while still continuing to actively pursue his philosophy of benevolence and morality.

It’s not until he gets back far enough that people begin to refer to the philanthropic entreaties they bring to this all-seeing, all-knowing, all-powerful, all-benevolent entity as "prayers" that he realizes that the joke’s on him and always has been…

Can anyone help me find this story again?