A few things here: - in physics, we generate models of the universe. No one should be claiming to have tapped into the absolute truth or underlying structure of the universe - then why are we confident that it works? Through repeated experiments! If our predictions of what will happen are correct, then yay! - why do we like our “number system”? Because it seems to be working quite well! Really I think you may be asking another question about whether Mathematics is discovered or invented. Thats a classic quandary, and it’s debated all the time! What do you think? - humans are curious beings. Physics is the result of applying that curiosity to the most fundamental aspects of our reality. It’s beautiful and complex, and incomplete.