We first ask the question in a way that Kant himself in fact did, namely: What resides in what-is-known in mathematical natural-scientific knowledge? What belongs to [>314] the known as such? This question is not asking about the totality of the results these sciences produce but rather about the thought-content of any and every result qua result of mathematical physics. To put it more precisely: not the thought content but rather what has to be thought, i.e., what belongs to the known as-such in any mathematical natural science. In the most general terms this known-as-such is nature.
Phenomenologically understood, nature is an entity which can be discovered within the world and of which it can be said that it underlies all worldly things and all worldly ontological connections insofar as they are determined by materiality—in short, nature can be found in everything of the world. Now, as such an entity, nature is accessible in various ways. In one instance, for example: we come to an understanding of nature by way of the things-of-use that are most immediately given in our lived world. For example, when I lift up a chair and let it fall, I can observe “falling” in that chair—because certainly the chair falls not because it is a chair but because it is consists of wood. Insofar as I understand it as nature, I have to first of all prescind from . . .—I prescind from it insofar as it is a chair. As regards this “falling” as a way of being, there is no difference between this chair and that walking stick or hat, or any other thing-of-use. That, then, is one way that nature becomes accessible: by way of an understanding that prescinds from the primary character of things.
We can also experience nature pre-scientifically in the direct way, as when I speak of a waterfall out there in nature, or of fir cones that fall from trees out there in nature, or of a chunk of stone that cracked off from a boulder and fell. So, I have nature in the sense of “nature out there” just as originally as I have chairs, tables, and hats. And this “nature outside” is the nature of physics and biology, although not yet as discovered in its specific way of being natural. When it is understood by natural science, this entity “nature” has to be understood as  an entity that is always there on hand and that, as something ever-there, goes through changes always in such and such a way.
So in our original natural experience we see, within the same context of being, both things-of-use that humans have produced out of natural materials and things-of-nature that humans have not produced but that have emerged either by growing or by some other process. And the whole field that includes both these types of things has the character of extension and localization. What is more, each of