Handbook of the History of Logic: - Fordham University Faculty

516 Simo Knuuttila
concepts of potency and impotency should be treated in the same way. According
to Anselm, ‘A is necessarily B’ properly ascribes a constraint to A and ‘A is possibly
B’ properly ascribes a capacity to A. Modal terms proper refer to properties
of things, such as the power to bring something about, or constraints caused by
other things. If modal terms are used in another way, they are used improperly.
Since Anselm regards the notion of capacity as the basic modal notion, something
is necessary in an improper sense with respect to causes which cannot prevent it,
and something is similarly impossible with respect to causes which cannot bring
it about. There are no constraining necessities proper in God, and divine impossibilities
are similarly analysed by referring to external impossibilities. In trying
to solve problems associated with the notions of freedom, sin and grace, Anselm
also employed the distinction between full and partial potencies. The shortcomings
of these analyses and some artificial constructions of the meaning of modal
statements based on the distinction between proper and improper capacity show
that the notion of potency is too narrow a basis for modal semantics. 24
1.3 Temporal modalities
A third ancient modal paradigm in Boethius meant for discussing singular possibilities
could be called the diachronic model of modality. In chapter 9 of Peri
hermeneias, Aristotle tries to qualify the necessity of the present — a corollary
of the lack of simultaneous alternatives in his theory — stating that not everything
which is actual is necessary simpliciter, without qualification (19a23-4). If
necessity without qualification means ‘necessary even without the temporal qualification’,
as Boethius reads it in his first commentary, Aristotle’s point would be
that the temporal necessity of actual events does not imply that such events are
necessary in themselves in the sense that they always take place in similar circumstances.
25 As already mentioned, this is a problematic attempt to qualify the
necessity of a definite singular event with the help of frequential considerations.
Some medieval and modern interpreters have opted for another interpretation:
Aristotle wanted to show that the necessity of an event at a certain time does
not imply that it would have been antecedently necessary. There are some places
in which Aristotle speaks about genuine singular possibilities with respect to definite
future points of time which may be realized or remain unrealized (De int.
19a13-17, EN III.5, 1114a17-19, Met. VI.3). 26 This idea of diachronic modalities
was considered important in the later Peripatetic tradition. It was argued against
Stoic determinism that there are genuine future alternatives which remain open
24 See E. Serene, ‘Anselm’s Modal Conceptions’ in S. Knuuttila (ed.), Reforging the Great
Chain of Being, Synthese Historical Library 20 (Dordrecht: Reidel, 1981), 117-62; S. Knuuttila,
‘Anselm on Modality’ in B. Davies and B. Leftow (eds.), The Cambridge Companion to Anselm
(Cambridge: Cambridge University Press, 2004), 111-31.
25 See Hintikka 1973, 147-175; Boethius, In Periherm. I.121.25-122.4.
26 This is a central theme in S. Waterlow, Passage and Possibility: A Study of Aristotle’s
Modal Concepts (Oxford: Clarendon Press, 1982); see also G.H. von Wright, Truth, Knowledge,
and Modality (Oxford: Blackwell, 1984), 72-8.