Handbook of the History of Logic: - Fordham University Faculty

520 Simo Knuuttila
tions. 42 While prophetic statements are formally future contingent propositions,
their being true is based on a revelation of atemporal knowledge. This is how
Aquinas tries to combine the doctrine of divine omniscience and the lack of definite
truth and falsity in future contingent propositions. 43 (See also 1.6 below.)
An influential formulation of divine foreknowledge was put forward by Peter
Abelard. William of Champeaux, one of Abelard’s teachers, dealt with an argument
against the compatibility between contingency and divine omniscience which
was discussed in Augustine’s City of God (V.9). In response to Cicero’s De fato
and De divinatione, Augustine refuted the claim that the possibility of events
having happened otherwise implies the possibility of error in God. William stated
that the antecedent of the argument is true but the consequent is false and therefore
the consequence is not valid. Peter Abelard, in discussing the same example
in his Dialectica and Logica ‘Ingrdientibus’, applied a systematic division which
he elsewhere drew between modal statements de sensu or in the compound sense
and modal statements de re or in the divided sense. 44 Abelard’s analysis of Cicero’s
argument was often repeated in medieval theology, since it was presented
in slightly modified form in Peter Lombard’s Sententiae, which became the standard
medieval introduction to theology. Abelard states that when the proposition
‘A thing can be otherwise than God knows it to be’ is taken to mean that it is
possible that a thing is otherwise than God knows, which corresponds to what he
elsewhere calls the de sensu reading, the antecedent is false. When the antecedent
is taken to say that a thing may be otherwise than God knows it to be, which
corresponds to what Abelard elsewhere calls de re possibility, the antecedent is
true, but the consequent is false, since if things were otherwise, God would possess
different knowledge of them. This shows that the consequence is not valid. 45
Following Peter Abelard, Peter Lombard formulated the same view in stating that
‘Things cannot be other than as God foreknows them’ is true in the compound
sense and false in the divided sense. The truth of the compound sense saves God’s
infallibility and the falsity of the divided sense expresses God’s freedom and the
42 Summa theologiae II-2.171.3.
43 For various interpretations of divine knowledge and future contingents in Aquinas, J.F.
Wippel, ‘Divine Knowledge, Divine Power and Human Freedom in Thomas Aquinas and Henry
of Ghent’ in T. Rudavsky (ed.), Divine Omniscience and Omnipotence in Medieval Philosophy,
Synthese Historical Library 25 (Dordrecht: Reidel, 1985), 213-41; Goris 1996, 213-54; W.L.
Craig, The Problem of Divine Foreknowledge and Future Contingents from Aristotle to Suarez
(Leiden: Brill, 1988), 103-26. See also J. Marenbon, Le tempts, l’éternité etlapresciencede
Boèce à Thomas d’Aquin (Paris: Vrin, 2005).
44 For this terminology, see Super Periermenias XII-XIV, ed. L. Minio-Paluello in Twelfth
Century Logic: Texts and Studies II: Abaelardiana inedita (Rome: Edizioni di Storia e Leteratura,
1958), 3-47. Later authors often used the expression de dicto instead of de sensu. See
below, section 2. For the historical background of Abelard’s argument, see J. Marenbon, The
Philosophy of Peter Abelard (Cambridge: Cambridge University Press, 1997), 226-8.
45 Peter Abelard, Philosophische Schriften I. Die Logica ‘Ingredientibus’, ed. B. Geyer,
Beiträge zur Geschichte der Philosophie und Theologie des Mittelalters XXI, 1-3 (Münster:
Aschendorff, 1919-27), 429.26-430.36; Dialectica, ed. L.M. de Rijk, Wijsgerige teksten en studies
1 (Assen: van Gorcum, 1956), 217.27-219.24.