Its not that phenomena couldn't be explained, but that they were still undiluted in their magical appearance. Man wasn't used to the magnificent powers of chemistry. All chemistry is "fire" in that it is plasma, and by mastering fire man began the science of chemistry. The sheer amount of chemical processes involved in cooking a fish is staggering. Fire changes the earth before mans eyes, and it brings the earth under his control. Gods are that primordial fire to stare in and wonder about, the things that give power but dont explain themselves.
