If we look at the way the universe behaves, quantum mechanics gives us fundamental, unavoidable indeterminacy, so that alternative histories of the universe can be assigned probability.

• Murray Gell-Mann

"it posits that the universe functions according to predictable rules"

• you

Not quite. Cosmologists accept a certain distribution of predictable phenomena within known parameters while leaving the door open to chaos, outliers, the as of yet unknown and unknowable.

Complexity theory is a model that posits components interact in multiple ways and behave according to local rules. From quantum physics to cosmology and the aspirational yet elusive grand theory of everything, science is prepared for a world weirder than we understand, and possibly weirder than we can understand.

Just because empirical evidence and the development of predictable rules are a very fruitful line of inquiry doesn't mean we believe that is truth.

Philosophers of Science have rather lengthy volumes of work on the subject. I'm just a novice on the topic, but my take on the state of the subject is that we don't accept science and even it's laws as absolute truth, just a very practical, reliable, utilitarian form of inquiry and understanding which includes uncertainty (Heisenberg), probability, complexity and chaos. Scientists are prepared to abandon everything in exchange for something better.

Look at newtonian physics. No one thinks it's the truth, it's just simpler and useful for everyday engineering.