Probability theory is fundamental. Outside of the quantum stuff it's some strange macro phenomena that occurs almost separate from physics.

It's strange, I'm no physicist but at the atomic level it seems particles are fundamentally probabilistic. But then even at a macro level completely separate from the underlying physics something like rolling dice will obey the laws of physics but also at a higher macro level it converges on following the laws of probability.

It's also connected with knowledge. I dunno... it's weird, when I think deeply about probability and why it works I get confused. It started with an interest in entropy as this weird macro law that somehow lives separate from physics, but then I realized entropy is just a consequence of probability.

Maybe probability is like logic. Something completely axiomatic. Eh I'm just rambling now.