  Whereas according to Augustine the sign, being an external entity by definition, was precluded from the sphere of the mind, it is now the mental sign, i.e., the mental concept or mental term (terminus mentalis), that is seen as the primary and most principal sign (signum mentale est primum et principalissimum signum, sine quo voces et scripta significare non possunt) (Florentius Diel, Modernorum summulae log., 1489, fol. a5v) as well as the ultimate ground of all  signification.[58]  Without such an ultimate and immediate signification instantiated in the formal signification of the mental concept, there would be, as John Raulin remarks, an infinite regress (processus in infinitum) in any signification, something like a Peircean ‘infinite semeiosis’.[59]  Unlike the infinite semeiosis of Peirce, however, such a regress, according to late medieval authors, would not have the character of a steady and permanent differentiation of signification but rather would be, as John Major calls it, an “abyss in signifying” (abyssus in significando) (John Major: Introd. perutile in Arist. dial. (1527: fol. 14ra), i.e., a process never resulting in a actual signification.