Functional Programing: is Real World Stateful?

in philosophy, there's two opposite thoughts, Idealism and Materialism. Mind exist only, or matter exists only.

if you go the ways of idealism, then the problem is everything becomes mental, a sorta taoism mumbo jumbo. Gets difficult in the ways of sciences.

if you go the ways of materialism, then you have a hard time conceptualize the mind, consciousness, and can never tell if you are in a dream.

Now, some say real world is states, not functions, even functional programers. You see? now you have the situation of idealism vs materialism.

we'd intuitively think the world is one world, with states. But, if functions, you have parallel universes, i.e. parallel programing.

the clojure inventor Rich Hickey, think of parallel worlds.