  Another contemporary source with information about the question is the discussion in Cur deus homo II.17 by Anselm of Canterbury, some thirty years later. Anselm makes a distinction between two kinds of necessity: there is preceding necessity (necessitas praecedens) and there is subsequent necessity (necessitas sequens). Preceding necessity is an efficient kind of necessity, and it is the cause of a thing’s being the case. The subsequent necessity does not cause anything, but is caused by a thing’s being the case. The necessity which follows from any true singular statement in any tense is subsequent necessity. Anselm’s discussion implies that the question about the consequence of necessity and impossibility arises from the failure to keep the two kinds of necessity separate (Knuuttila 1993, 74; Knuuttila 2004, 122–124; Marenbon 1996, 12–16; Holopainen 1999; Binini 2017, 251–253).