Another Interpretation of Aristotle's De Interpretatione IX A support for the so-called second oldest or 'mediaeval' interpretation JOB VAN ECK Controversies regarding propositions about the future, occasioned by Aristotle's De Interpretatione IX have occurred throughout the history of logic from Antiquity to the 20th century, especially in the Middle Ages. The question under discussion is: must some such propositions be denied a truth value in order to escape determinism? Or does the law of bivalence also hold for future contingency propositions? And what is Aristotle's position in De Interpretatione IX? Does he say that bivalence implies determinism and thus abandons universal bivalence (this is called the oldest, or traditional, interpretation), or does he reconcile bivalence with indeterminism (the so-called second oldest in- terpretation). Boethius, in his two commentaries on De Interpretatione, shows himself a representantive of the second oldest interpretation. His main thesis is that according to Aristotle it is necessary for a future con- tingency proposition and its negation that one is true and the other false, but not definitely true, nor definitely false. In a recent article Pro- fessor Norman Kretzmann stressed the influence this point of view of Boethius has had on the subsequent discussion' . The second oldest interpretation became so prominent among mediaeval philosophers that some call it the mediaeval interpretation. In modern times most authors reject this interpretation, partly because the phrase "definitely true", which is at the heart of it, is rather obscure and its Greek analogue alêthes aphorismends does not oc- cur in De Interpretatione IX at all. Therefore it is worthwhile to return here to the original Aristotelian text itself, not only because of its im- portance for the hot issue of future contingency propositions in Norman Kretzmann, Boethiusand the truth about tomorrow'ssea battle, in: Logos and Pragma. Essays on the philosophy of language in honour of professor Gabriel Nuchelmans, ed. by L. M. de Rijk and H. A. G. Braakhuis, Nijmegen 1987, 63-97. 19 mediaeval philosophy in general, but also, and more particularly, because of the question whether the second oldest interpretation can be warranted. I think it can be if we take the phrase "definitely true" as an equivalent of the "already true" of 19a36, thus connecting it with a temporal notion of necessity, or historical necessity. Most authors on De Interpretatione IX nowadays agree that a notion of historical necessity plays a certain part in the chapter. However this has not yet been exploited to the full, because either one does not ap- preciate the way this concept of necessity may be used (and in fact is used by Aristotle) in order to make a strong case for determinism, or, even if one sees the deterministic argument as "an argument from the past truth", one does not seem to realise the crucial role this necessity of the past plays in the chapter as a whole. The strong implications of its logic, that haunt the chapter from the very beginning, are easily overlooked; as a result the two current families of interpretation that have been advocated in the course of time have remained un- satisfactory. In the following I will offer an alternative interpretation, but first I shall give a translation of the most important parts of the chapter in three sections, each followed by a preliminary comment2. Translation of the crucial parts of De Interpretatione IX and preliminary comments The chapter opens as follows3 I 18a28-34 With regard to what is and what has been it is necessary for the affirma- tion or the negation to be true or false. And with universals taken universally it is always necessary for one to be true and the other false, and with particulars too, as we have said; but with universals not spoken of universally it is not necessary, but with particulars that are going to be not in the same way4. For an extended bibliography on the subject of De InterpretationeIX see D. Frede, The Sea Battle Reconsidered:A Defenceof the Traditional Interpretation,Oxford Studies in Ancient Philosophy, III (1985), 31-87. For the most part I will use Ackrill's translation in Aristotle's Categoriesand De Inter- firetatione,tranlated with notes by J. L. Ackrill, Oxford 1963. I will indicate in foot- notes where I deviate from it. Preferring variants that are closer to the Greek text may seem pedantic, the more so because the result is nearly always more distorted English, but I find we need them for a better understanding. The division in (sub)sections is mine. The Greek text I use is AristotelisCategoriae et Liberde Interpretatione,ed. L. Minio- Paluello, Oxford 1949. 4 ouch homoiôs;Ackrill, "it is different". 20 .