Why do I believe that the universe is lawful? Because it appears lawful, and due to reasons discussed in other replies to my post, and my common sense has marked the alternative as insane.

Well then, there's how you:

distinguish between the hypothesizes that the universe is lawful, and the hypothesis that the universe is determined by my beliefs, and I believe it to be lawful.

You observe lawfulness, not just believe in lawfulness. Whatever the source of that lawfulness, the lawfulness itself is right there in your observations.

Is it lawful independently of you, or is it lawful because you are God but have forgotten yourself? I suppose you could seek out and practice spiritual exercises to remember your true being as God, and only if that fails to produce a smidgen of miracle-working ability, consider that you might not be God after all. But "we are subject to physical law because we have forgotten our divine nature" is already too much like claiming to have an invisible dragon.