As early peoples caught glimpses of the divine in art or in nature, it must have been natural to think there were gods in things. In fact, I had been told.
Some elements of polytheism are merely superstitious, but other aspects are genuinely responsive to the many ways in which I present myself. It may seem odd to your modern mind to think of fire as a god, but why do you think I made fire mysterious and fascinating? It is a physical metaphor in itself—it is created out of nothing and disappears into nothing, grows and dies, gives life and warmth as well as pain and destruction, and it looks both hypnotically attractive and frightening.
As you know, I am very powerful. I do manifest Myself in storms and thunder, in the ocean and great waves—in the power that drives the universe and that manifests itself in each particular event. The large cosmic forces are divine and so are their concrete manifestations in specific incidents. That does not mean that every rainstorm is a specific communication or is there to advance or retard some particular action, but it does mean that every rainstorm expresses an aspect of Me.
Early peoples saw My presence everywhere, saw the spiritual indwelling of things, their powers and potencies and the divine element in all that. But there was always an awareness, however dim, that there was a single spiritual reality behind them all.