Nature is one of a cluster of “nat” words that are all rooted in the idea of birth (natal and nativity show this simply, and “nation” and “native” connote a common birthplace and one who was born in the place). The “nat” roots started off as “gen-uh” but in Latin the “n-uh” swallowed up the g sound (though not for the Latin “genus”, “gens” or all of the cognates). This is all to say that the root idea in all the words is that of birth or coming forth.
Implicit in the idea of birth is that the coming forth happens from something within the thing that comes forth. Trees and animals and men and even the oceans and the tides come forth “on their own” and apart from human art. The principle of their coming forth is within- sometimes this happens in a very active sense, as in living beings, sometimes the principle of coming forth is only verified in a passive sense, like happens in the tides or in evolution or the motion of the planets. But in all cases there is a pretty clear distinction between nature and art.
Nature, then, will always connote a certain source of activity and existence within. This is opposed to an artifact, which has no source of existence within. All artifacts begin to fall apart as soon as they are made- which is clear to anyone who works maintenance or has to keep things running smoothly. Natural things, for the most part, fix themselves and provide for their continued existence. All art becomes ruins, all nature arises again- I can look at the same roses as Virgil, but not the same buildings.
Although the sense of nature we are speaking about now is not the exact sense of nature we use when we speak of certain acts being contrary to nature or according to nature, there is a common note between them: all that is contrary to nature in the moral sense has no source within to keep it in existence, and all immorality involves a certain rejection of the interior source of existence that is within things, and which is always in a certain sense opposed to the human will as a principle of making.
