There are the myths that say there was a beginning, and those that say the Universe has always been, and that you can step in the same river twice. Ralph Waldo Emerson's first book, which appeared in 1836, was titled, simply, Nature . He walked close up to the fall, and, after looking at it a moment, with an air as if thinking how he could best appropriate it to his own use, he spat into it. But then, there have always been those who looked to Nature as our best Teacher, and with good reason, because we are Nature, and not something separate from Nature. Nature as Teacher.
Nature is all one stuff.
We are the discovers of Nature's secrets, but we are one of Nature's secrets still unknown to whatever intelligent life exists out there beyond the little place we inhabit in spacetime. And a guiding identity runs through all the surprises and contrasts. We do not understand the mysteries of gravity, or electromagnetism, or consciousness, but there they are, not waiting for us to penetrate their mysteries. Nature confronts us as a vast promise, its secret untold. No archangel can follow a rainbow to tell of its source.