Your correct. You'd have to run the universe simulation a bunch and pick the most probable outcomes (which makes you the most brutal serial killer in existence). The probability graph would represent the state stability of the underlying structures that guide what you're trying to measure.

In weather you have things that are chaotic, but follow rules and don't create them. Things can surprise you, but you'll mostly center around particular solutions.

With humans this gets a lot more complicated because you are messing with systems that follow fixed rulesets (chemistry) and things that follow self modifying rulesets (social conventions). A very unstable system on top of a semi-chaotic probability state.

A good example of this would be if I deleted the concept of rain from the human mind and all of human history and knowledge. Humanity would be very surprised on the thunderstorms that popped up, but they'd continue on just as they did before.

Now lets imagine I delete the concept of all gods. Would the idea of gods come back, for sure. Would they look like our gods now. Very questionable indeed. We wouldn't be getting jesus back. And the new set of religions could have wildly large effects on how the people act.