… fact becomes shadow, law becomes probability.
This is from the essay ‘Thoreau’s Vision of the Natural World’ found in The Star Thrower by Loren Eiseley (1978):
… Behind all religions lurks the concept of nature. It persists equally in the burial cults of Neanderthal man, in Cro-Magnon hunting art, in the questions of Job and in the answering voice from the whirlwind. In the end it is the name of man’s attempt to define and delimit his world, whether seen or unseen. He knows intuitively that nature is a reality which existed before him and will survive his individual death. He may include in his definition that which is, or that which may be. Nature remains an otherness which incorporates man, but which man instinctively feels contains secrets denied to him.
A professional atheist must still account for the fleeting particles that appear and vanish in the perfected cyclotrons of modern physics. We may see behind nature a divinity which rules it, or we may regard nature itself as a somewhat nebulous and ill-defined deity. Man knows that he springs from nature and not nature from him. This is very old and primitive knowledge. Man, as the “thinking reed,” the memory beast, and the anticipator of things to come, has devised hundreds of cosmogonies and interpretations of nature. More lately, with the dawn of the scientific method, he has sought to probe nature’s secrets by experiment rather than unbounded speculation.
Still, of all words coming easily to the tongue, none is more mysterious, none more elusive. Behind nature is hidden the chaos as well as the regularities of the world. And behind all that is evident to our senses is veiled the insubstantial deity that only man, of all earth’s creatures, has had the power either to perceive or to project into nature.
As scientific agnostics we may draw an imaginary line beyond which we deny ourselves the right to pass. We may adhere to the tangible, but we will still be forced to speak of the “unknowable” or of “final causes” even if we proclaim such phrases barren and of no concern to science. In our minds we will acknowledge a line we have drawn, a definition to which we have arbitrarily restricted ourselves, a human limit that may or may not coincide with reality. It will still be nature that concerns us as it concerned the Neanderthal. We cannot exorcise the word, refine it semantically though we may. Nature is the receptacle which contains man and into which he finally sinks to rest. It implies all, absolutely all, that man knows or can know. The word ramifies and runs through the centuries assuming different connotations.
Sometimes it appears as ghostly as the unnamed shadow behind it; sometimes it appears harsh, prescriptive, and solid. Again matter becomes interchangeable with energy; fact becomes shadow, law becomes probability. Nature is a word that must have arisen with man. It is part of his otherness, his humanity. Other beasts live within nature. Only man has ceaselessly turned the abstraction around and around upon his tongue and found fault with every definition, found himself looking ceaselessly outside of nature toward something invisible to any eye but his own and indeed not surely to be glimpsed by him.