[smtucker]

Simple doesn't necessarily mean easy to understand, particularly when the thing doing the understanding is part of (and constrained by the rules of) the system being analysed. It is conceivable that there are simple aspects about our universe we will never understand because they are hidden behind some threshold of observation.

[rndn]

Exactly. I was trying to say that equivalently to "the unreasonable effectiveness of mathematics", we could also wonder at "the unreasonable simplicity of physical laws" (simple in the sense that we are able to understand the properties of it—at least superficially, but often also deeply). There is perhaps also an anthropic principle here: If the systems we find ourselves in would be much more complex, life would have likely been unable to form as prediction and organization would have been too difficult.

It's actually hard to quantify simple systems so perhaps I should have replaced the word "most" with "many" in my comment above. There are also typos e.g. s/its/their/, sorry for that.