Maybe I'm misunderstanding something. I've always supposed that we do live in a multi-tiered causal universe. It seems to me that the "laws of physics" are a first tier which affect everything in the second tier (the tier with all of the matter including us), but that there's nothing we can do here in the matter tier to affect the laws of physics. I've also always assumed that this was how practically everyone who uses the phrase 'laws of physics' uses it.

So you mean we live in a multitier universe with no bridging laws and the higher tiers are predictable fully from the lower tiers? Why not just call it a single tier universe then? Especially because your hypothesis is not distinguishable from the single-tier, which is simpler, so you have no good reason to ever have encountered it. "Such and such is true, but that has no causal consequences, but it's truth is still somehow correllated with my belief". (note that that statement violates the markov-whatsit assumption and breaks causality).

Forgive me if I misunderstood.