Most of the early scientific practices rooted in alchemy are based on the belief that one must taste, touch, see, feel, hear and smell a tangible result--and be able to duplicate it--rather than take the results for granted.
Our history has produced mechanical science as its primary tool for technological advancement; the FMA history produced alchemy to the same ends.
There's a bit of a debate in classics over whether or not the Fates are the supreme beings of the world, whose power cannot be trumped even by Zeus, King of the gods.
Who can do alchemy? If alchemy is a route to understanding/embracing one's own godhood, do all humans have such godhead potential as a state of being human?