Is the universe's behavior such that it's literally impossible for anything other than those things that lie within its natural law to happen

...Or is it simply a very efficient and, as far as we've observed, perfectly working system for making it the case that its current behavior is perpetuated?

To put this another way, is the universe's behavior analogous to a jello fitting perfectly into a mold because that's all it can do, or is it more analogous to a mechanical machine being propelled to behave as it does due to internal mechanisms which are in this case just very robust, to the point where we can't even see them?