Handbook of the History of Logic: - Fordham University Faculty

534 Simo Knuuttila
Socratem currere’. When this is understood in accordance with its grammatical
construction, it is not a genuine modal proposition, the mode itself being said of
the grammatical subject which is the accusative and infinitive phrase. The nominal
mode can also be understood in an adverbial manner, however, in which case
the proposition expresses a modalized predication. 96 In Abelard’s view, these and
some further ambiguities demanded a systematic investigation of the properties
of various propositions including modal terms. In his approach, grammatical distinctions
were transformed into a logical distinction between de sensu modes and
de re modes. Abelard states that in the present treatise he uses the terms de
sensu and de re in the same way as Aristotle uses the expressions ‘in a compound
sense’ (per compositionem or coniunctionem) and ‘in a divided sense’ (per divisionem)
inSophistici elenchi 4, 166a23-30, and that the distinction, understood
in this way, maintains an inference from an affirmative possibility proposition de
sensu to a corresponding affirmative possibility proposition de re. When possibility
propositions de sensu are interpreted in a compound sense, both de sensu
readings and de re readings are in fact de re readings which express modalized
predications about actual things. The difference between these is that a modal
proposition de sensu in a compound sense asserts that a subject which is said to
have a predicate possibly, necessarily, or impossibly has it together with all descriptions
of the subject mentioned in the proposition. A modal proposition de re
does not imply this combination. 97 The compound de sensu reading of ‘An F is
necessarily/possibly/impossibly G’ is:
(7) An x which is F is necessarily/possibly/impossibly G while remaining F
and the de re reading is
(8) An x which is F is necessarily/possibly/impossibly G.
In addition to this analysis, Abelard mentions that de sensu modalities can also be
understood in an impersonal manner in which case they do not refer to capacities or
incapacities embedded in actual beings but instead to what can or cannot be. A de
sensu possibility proposition in this strict sense does not imply a de re possibility
proposition with an existential import. Abelard’s examples are ‘Every substance
is a spirit’ and ‘My son is living’ said by a person not having a son. These are not
true in the Aristotelian sense, but possible in the sense of what is not repugnant
to nature. 98 The differences between Abelard’s strict de sensu — reading and (7)
and (8) could be expressed in standard modern notation as follows:
(9) ♦Ex(Fx & Gx)
96 Super Periermenias 3.7-11.16.
97 Super Periermenias 13.15-14.4; 30.25-31.10.
98 Super Perihermenias 29.13-30.25; cf. 20.13-21.15. For impersonal modal constructions in
Abelard, see K. Jacobi, ‘Diskussionen über unpersönliche Aussagen in Peter Abaelards Kommentar
zu Peri hermeneias’ inE.P.Bos(ed.),Medieval Semantics and Metaphysics, Artistarium
Supplementa 2 (Nijmegen: Ingenium Publishers, 1985), 30-40.