The terms, substantial necessity and substantial possibility […] refer to supposed information of the present in the present, including among the objects known all existing laws...
From the Robin Catalogue:
A. MS., G-1893-5, pp. 85-141 (pp. sog, 130 missing), with 8 pp. of variants.
Published, in part, as 4.53-56 (but not all of 56) and 4.61-79 (...