Two senses of ‘Nature’ in MFNS
- ‘Nature’ in its formal meaning: ‘the first inner principle of everything that belongs to the existence of a thing’ (4:467)
- ‘Nature’ in its material meaning: ‘The sum of all things, insofar as they are object of our senses’ (4:467)
From @plaass1994:
The development of these concepts in Kant can be followed from an unpublished sketch around 1773-5 (Reflexion 40, AA XIV, 118, L.Bl.), in which the distinction is not made at all and only the material meaning of the word is used in order to define the concept of naœtural science. It proceeds via the first edition of the Critique (comp. e.g., A 216, B 263; A 418, B 446 notes), the Prolegomena, where in §§ 14 and 16 (AA IV, 294 and 295f) it is more precisely elaborated, and the Groundwork of the Metaphysic of Morals of 1785 (AA IV). After the MF, e.g., in the second edition of the Critique (B 163ff), the two-fold meaning is fixed in the sense made precise here.
Essence
Essence is ‘that upon which the inner possibility of a thing rests’ (4:511)