The principle Truth remains True that there is some sort of building-blocks that compose the universe.

But that's just a convention we've come to see as useful because, like you said, it has shown to be useful over and over (again, by convention).

I'd say without shared consensus on useful conventions, we don't have progress. There have been inaccurate scientific claims in the past which still brought about progress because as more people used them, we eventually found flaws and improvements which led to even better conventions and new discoveries.

We only "prove laws in nature" by our shared conventions such as the scientific method. We find direction based on how effective our epistemology is for predicting future events and describing physical reality as we observe it.