Natura Naturans
Nature always in the process of becoming; nature "naturing" (WCT 25). "Nature in the active sense" (Coleridge, WCT 24). Nature not phenomenal, but nonetheless real, "supersenuous, but not supernatural" (WCT 25). What we call "laws of nature" were once experienced as natura naturans.

Greek thought was at home in natura naturans and was, in fact, a direct experience of it (RCA 54-55). In the minds of the Naturphilosophen [Schelling, etc.], natura naturans was essentially one with "what we call intelligence" (RM 182).

Natura naturans is equivalent to what Steiner calls the etheric (RM 182).

See in particular "Naturata and Naturans" (WCT 22-25).