Handbook of the History of Logic: - Fordham University Faculty

512 Simo Knuuttila
by what he does at other times. According to Boethius, this shows that sitting
as such does not inhere in Socrates by necessity (II.242.22-243.2). Many twelfth
and thirteenth century authors applied this analysis in discussing the sentence ‘A
standing man can sit’, adding to the true divided (or de re) reading ‘at another
time’ or something similar. 15 Another Boethian strategy was to refer to antecedent
contingency; I shall return to this in 1.3 below.
Even though there are many examples of the frequential use of modal terms in
Western authors from Boethius to Thomas Aquinas, they did not define modal
terms through the ideas of various degrees of generality or changing and unchanging
truth. 16 These aspects of modalities were regarded as concomitant rather than
definitional. Modifying Boethius’s classification of ancient theories from this point
of view, Thomas Aquinas writes that:
Some who distinguished them by results – for example Diodorus – said
15 See, for example, the anonymous texts in De Rijk 1962, 210.10-17; 311.8-15; 316.1-7; 613.23-8;
De Rijk 1967 (II.2), 687.28-688.1; William of Sherwood, Introductiones in logicam, ed. M.Grabmann
in Sitzungsberichte der Bayerischen Akademie der Wissenschaften, Phil.-hist. Abteilung
1937, 10 (Munich: Verlag der Bayerischen Akademie der Wissenschaften, 1937), 90.11-24, trans.
with an introduction and notes by N. Kretzmann in William of Sherwood’s Introduction to Logic
(Minneapolis: University of Minnesota Press, 1966), 141-2; Peter of Spain, Tractatus VII.68,
70-1; Lambert of Auxerre, Logica, ed. F. Alassio (Florence: La Nuova Italia, 1971), 158.
16 For an equation of modal and temporal notions (necessarily-always, possibly-sometimes), see
Averroes’s commentary of Aristotle’s De caelo in Aristotelis opera cum Averrois commentariis
(Venice 1562-74), vol. V, 84A-D, 87H-M, and Avicenna’s treatise al-Masa’il, quoted in T. Street,
‘Fahraddīn Ar-Rāzī’s Critique of Avicennan Logic’ in D. Perler and U. Rudolph (eds.) Logik und
Theologie. Das Organon im arabischen und lateinischen Mittelalter, Studien und Texte zur
Geistesgeschichte des Mittelalters 84 (Leiden: Brill, 2005), 104. Further typical examples are
the principles that if something can be destroyed, it will be destroyed (Moses Maimonides, The
Guide of the Perplexed, trans. with introduction and notes by Sh. Pines (Chicago: University
of Chicago Press, 1974), II, 247, 249; Thomas Aquinas, Summa theologiae, ed. P. Caramello
(Turin: Marietti, 1948-50) I.2.3; In Post. an. I.13, 117; cf. Aristotle, Metaphysics XII.6),
what is possible with respect to a species will be actualized (Moses Maimonides in a letter to
Samuel ibn Tibbon, quoted in Ch.H. Manekin, ‘Problems of ‘Plenitude’ in Maimonides and
Gersonides’ in R. Link-Salinger, R. Long and Ch.H. Manekin (eds.), A Straight Path: Studies in
Medieval Philosophy and Culture. Essays in Honor of Arthur Hyman (Washington: Catholic
University of America Press, 1988), 187, and that universal propositions are false and particular
propositions are true in contingent matter (De Rijk 1967, II.2, 115.5-12; 138.24-6; Albert the
Great, Commentarius in Perihermenias, inOpera omnia, ed. A. Borgnet, vol. I (Paris: Vivès,
1890), 5.6, 422, and the texts mentioned in note 8 above). Gersonides also assumed that all
genuine possibilities will be actualized; see The Book of Correct Syllogism I.1.14 in The Logic of
Gersonides. A Translation of Sefer ha-Heqqesh ha-Yashar (The Book of the Correct Syllogism),
with introduction, commentary, and analytical glossary by Ch.H. Manekin, The New Synthese
Historical Library 40 (Dordrecht: Kluwer, 1992). One of distinctions between modalities per
se and per accidens, which were employed in logical treatises, was based on the idea that the
modal status of a temporally indefinite tensed proposition may be changeable. According to
the early thirteenth-century Logica ‘Ut dicit’, true future tense singular propositions referring to
non-existent future things, such as ‘The Antichrist will be existent’, are necessary per accidens,
for they cannot have been false in the past nor false now, though they will be false in the future
(de Rijk 1967, II.2, 390.21-2);‘necessarily’ is said to mean the same as ‘in all times’ in this treatise
(411.8-9). It was more usual to associate accidental necessities and impossibilities with past tense
singular propositions; see note 111 below. Peter of Spain wrote that ‘Antichrist has not been’
will be accidentally impossible, though it is true now (Tractatus IX.4).