I decided to simplify the argument from the last post to post in the comments on the Templeton Big Question site, "Does Science Make Belief in God Obsolete?" Before offering the argument, however, I'd like to note two objections and my rejoinder to teach.
Objection 1: Metaphysics is the projection of human grammar into a realm beyond where it has any knowable object.
Reply to Objection 1: The following argument is an entailment of language used in science as it engages this world.
Objection 2: Arguments for Belief in God are attempts to know something inherently metaphysical. Ergo, go back to objection 1.
Reply to Objection 2: To say that something is entailed metaphysically is not to say that it is known. For instance, immense gravitational fields have led physicists to posit dark matter. One does not need to know what dark matter is to posit that there is something that creates the gravitational field. The same holds for the eternal being entailed in the argument to follow.
The Simplified Argument:
To explain something scientifically requires explaining how it came to be (or how it brings something else about). Consequently, something that has always been cannot be explained scientifically. But "has always been" has two relevant meanings here: 1. "has always been" temporally, and 2. "has always been" as the source of being for what is here now. For purposes of scientific explanation, however, "has always been temporally" depends for its coherence--literally--on "has always been as a source of being for what is here now" (otherwise temporal succession would comprise ontologically discrete elements with respect to being, and there could--literally--be no coherent explanation of how the discrete elements in the temporal sequence came to be). But as already noted, what has always been cannot be explained scientifically. Therefore, either there is no scientific explanation, or there is being that has always been as a source of being for what is here now, and such a being cannot be explained scientifically. But there is scientific explanation. Therefore, there is a scientifically mysterious eternal source of being for what there is here now, which we refer to as God.