Aquinas and Ockham on Time, Predestination and the Unexpected Examination

AQUINAS AND OCKBIAM ON TIME, PREDESTINATION AND THE UNEXPECTED EXAMINATION1 The unexpected examination paradox seems to have surfaced sometime in the 1940s, but has a solution which appeared before 1324. Although the paradox is typically presented as a problem in epistemic logic, it may be viewed as being, at bottom, a matter of modal logic, and Ockham's combination of modal and tense logic, as developed particularly in his Tractatus de Praedestinatione,2 and subsequently systematized by Prior and others, gives us the conceptual tools we need to deal with the problem. Ockham built on a well established foundation concerning the notion of time and, though in de Praedestinatione he pays more direct attention to the views of Scotus, I begin by sketching the contribution of St. Thomas Aquinas. There are strong similarities, as well as sharp differences, in the views of Ockham and Aquinas on time, and Ockham's originality is not called in question by noticing those 1An earlier version of this paper was given at The Arthur Prior Memorial Conference in Philosophy and Logic, held in Christchurch, New Zealand in 1989, preprinted Hi the Auckland Philosophy Papers series (1990.1) as "Aquinas, Ockham, and Prior (and the unexpected examination)." This version of the paper has benefitted from comments made during that session, and particularly from subsequent comments by Christopher Martin of the University of Auckland. William Ockham, Tractatus de Praedestinatione et de Praescientia Dei Respectu Futurorum Contingentium (hereafter DP), in Opera Philosophica II, ed. Philotheus Boehner (New York: St. Bonaventure, 1978). The Tractatus de Praedestinatione has been translated with a commentary by Marilyn McCord Adams and Norman Kretzmann as William Ockham: Predestination, God's Foreknowledge, and Future Contingents (Indianapolis: Hackett Press, 2nd ed., 1983, hereafter AK). AK also includes three very useful appendices: Appendix I contains Distinctions 38 and 39 of Scriptum in Librum Primum Sententiarum (Ordinatio), Distinctiones XTX- XLVIII, ed. G. I. Etzkorn and F. E. Kelley, Opera Theologica IV, (New York: St. Bonaventure, 1979). Appendix II contains the commentary on ch. 9 of In Perihermenias: Expositio in Librum Penhermenias Aristotelis, in Opera Philosophica II, ed. A. Gambatese and S. Brown (New York: St. Bonaventure, 1978). Appendix ?? contains most of ch. 32 oí Summa Logicae III.3, in Opera Philosophica I, ed. P. Boehner, G. Gal, S. Brown (New York: St. Bonaventure, 1974). See also A. N. Prior, Past Present and Future (Oxford: Clarendon Press, 1967) and, for development and discussion of Prior's Ockhamist system, R. Thomason, "Combinations of Tense and Modality," Hi D. Gabbay and D. Guenthner, eds., Handbook of Philosophical Logic, II (Dordrecht: D. Reidel), 135-165. 181 Franciscan Sludies, 55 (1998) 182J. J. MACINTOSH similarities.3 The question of which tense logic theorems Ockham accepted or was committed to is still an open question, and in the section on Ockham I offer some suggestions before going on to consider how an Ockhamist view of time leads to a resolution of the unexpected examination paradox. I AQUINAS For St. Thomas as for Ockham, the discussion was conducted against a theological background which provided a number of important shared epistemic assumptions and concepts. In particular, this background provided (i) contingently applicable predicates which appear to have built-in futurity such as 'reprobate' or 'predestinate'; (ii) cases of knowledge of future contingents;4 (iii) an account of the kinds of knowledge about the future it is possible for humans (or any created entity) to have, and of the dangers of trying to have any other kind of knowledge about the future, though this seems to have weighed more heavily with Aquinas than with Ockham, a fact which reflects the differing depths of their 3For a discussion of the background to Ockham on future contingents see Calvin Normore, The Logic of Time and Modality in the Later Middle Ages: The Contribution of William of Ockham (diss., U. of Toronto, 1975, National Library of Canada No. TC35093), and "Future Contingents," Hi N. Kretzmann, A. Kenny, and J. Pinborg, eds., The Cambridge History of Later Medieval Philosophy (Cambridge: Cambridge University Press, 1987); and M. McCord Adams, William Ockham 2 vols. (Notre Dame: University of Notre Dame Press, 1987), especially chs. 20, 27, and 31. For the relation between...