The passage below is the seventh chapter of Ockham's master work, the Summa of Logic, in parallel Latin English translation. It concerns the truth conditions of past and future tense propositions (i.e. sentences - the Latin 'propositio' is what we would now call a sentence). Such propositions present a difficulty for the nominalist semantics of Ockham, for they are about events, and possibly things, that do not exist in the present. Given that Ockham's theory is in part a theory of what makes propositions true, what is that that makes past and future tense propositions true?
His answer is not altogether easy to follow, or to translate. Ockham, in common with the other 'terminist' logicians, holds that a proposition of the form 'Some A is a B' is true when the common terms A and B both 'denote' the same thing. (Note: the English word 'denote' is what I have used to translate the Latin word 'supponere' - other translators typically use the invented word 'supposit'). But in specifying these truth conditions, we use a present tense sentence. We say the subject and the predicate term denote (i.e. denote NOW) the same thing. But if that is true now, isn't some state of affairs true now? And if so, how does this state of affairs differ from what is asserted by the tensed proposition? If it does not differ, the tensed state of affairs is a current state of affairs, and so the proposition is apparently not tensed. If different, in what way are the truth conditions really truth conditions?
Ockham's answer is almost impossible to follow. He says that the predicate must be predicated of the subject 'under its own form' (sub propria forma). But what does that mean? He also says that it is not sufficient that the thing which the subject denotes is that which the predicate denotes. The thing which the subject denotes must be that which the predicate denotes by means of what is asserted (denotatur) by such a proposition. This, again, is not easy, but does he mean that denotation by a common term is itself qualified by tense - that 'white' may not denote Socrates now, but that it once did, or may do in the future? Or is it, as Catarina Dutilh Novaes suggests in a recent work, that 'denotatur' is the key to understanding Ockham's theory of the proposition, particularly regarding empty terms. In 'a chimera is white', what does 'chimera' denote, if there are no chimeras? Ockham's reply is that in such a proposition, though the term does not denote, it is asserted (denotatur) to denote, and that it is this assertion that determines the truth value. Similarly, 'Socrates was white' is true in some state of affairs (now past) where Socrates was white. What makes the proposition true is not some existing state of affairs, but what is asserted or meant (denotatur) by the proposition.
Note also Ockham's use of the term 'demonstrando'. This is often translated as 'by pointing'. However Ockham says 'demonstrando illum pro quo 'creans' supponit', and one cannot surely point to the divine Creator. Hence I have followed Freddoso in translating it as 'by referring'. Hence we should not confuse medieval ideas about 'supposition' or denoting, which is what common terms like 'man' and 'white' do, with what is now called 'reference', which is what demonstratives do. (This is also something that Dutilh Novaes has argued).
Dutilh Novaes, C., Formalisations Apres la Lettre, Alblasserdam 2005
|2.07 DE PROPOSITIONIBUS DE PRAETERITO ET DE FUTURO||On propositions in the past and future tense|
|Quarto videndum est de propositionibus de praeterito et de futuro.||Fourth, we must look at propositions in the past and future tense.|
|Et est primo sciendum quod quaelibet propositio de praeterito et de futuro, in qua subicitur terminus communis vel pronomen demonstrativum cum termino communi vel terminus discretus importans aliquod compositum, est distinguenda, eo quod subiectum potest supponere pro eo quod est vel pro eo quod fuit, si sit propositio de praeterito, aut pro eo quod est vel pro eo quod erit, si sit propositio de futuro.||It should first be known that any proposition in the past and future tense, in which the subject is a common term, or demonstrative pronoun with a common term, or a discrete term signifying something composite, is to be distinguished, for the subject can denote that which is or that which was (if the proposition is past tense), or that which is or that which will be (if the proposition is future tense).|
|Et sive sic sive sic, si sit propositio affirmativa requiritur quod praedicatum sub propria forma, hoc est quod ipsummet praedicatum vere per tale verbum praedicetur de eo pro quo subiectum supponit, ita scilicet quod propositio in qua praedicatur praedicatum de pronomine demonstrante praecise illud pro quo subiectum supponit fuit aliquando vera, si sit propositio de praeterito, vel quod erit aliquando vera, si sit propositio de futuro.||Either way, if the proposition is affirmative it is required that the predicate under its 'own form', that is, that the very same predicate is truly predicated, by means of such a verb, of that which the subject denotes; in other words, that the proposition in which the predicate is predicated of a pronoun referring precisely to that which the subject denotes was once true (if it is a past tense proposition) or will at some time be true (if it is a future tense proposition).|
|Verbi gratia, si ista propositio sit vera'album fuit Sortes', et si 'album' supponat pro eo quod est album, non requiritur quod haec fuerit aliquando vera 'album est Sortes', sed requiritur quod haec fuerit vera 'hoc est Sortes', demonstrando illud pro quo subiectum supponit in ista 'album fuit Sortes'.||For example, if the proposition 'A white thing was Socrates' is true, and if 'white' denotes something that is white, it is not required that 'A white thing is Socrates' has ever been true, although it is required that 'this is Socrates' was true, referring to what is denoted by the subject of 'A white thing was Socrates'.|
|Unde si Sortes nunc primo sit albus, haec est vera 'album fuit Sortes', accipiendo subiectum pro eo quod est, et tamen numquam haec fuit vera 'album est Sortes', sed haec fuit vera 'hoc est Sortes', demonstrando Sortem; et quia 'album' in ista 'album fuit Sortes' supponit pro Sorte, ideo haec est vera.||Wherefore, if Socrates is now white for the first time, 'A white thing was Socrates' is true, by taking the subject for that which exists [now], nevertheless 'A white thing is Socrates' was never true, although 'this is Socrates' was true (referring to Socrates); and because 'white thing' in 'A white thing is Socrates' denotes Socrates, it is true for that reason.|
|Similiter ista est modo vera 'creans ab aeterno fuit Deus', et tamen haec non fuit ab aeterno vera 'creans est Deus', sed ista ab aeterno fuit vera -- vel fuisset vera, si fuisset formata -- 'iste est Deus', demonstrando illum pro quo 'creans' supponit in ista 'creans ab aeterno fuit Deus'.||Similarly, 'A thing which creates was from eternity God', is now true, yet 'A thing which creates is God' was not true from eternity, although 'This is God' was true from eternity (referring to what is denoted by 'thing which creates' in 'A thing which creates was from eternity God'.|
|Similiter ista est vera 'puer erit senex', et tamen haec nunquam erit vera 'puer est senex', sed ista erit vera 'iste est senex', demonstrando illum qui modo est puer. Et ita est de aliis.||Similarly 'A boy will be old' is true, yet 'a boy is old' is never true, although 'this is old' will be true, referring to that which now is a boy. And so for other propositions.|
|Unde ista est differentia inter propositiones de praesenti et de praeterito et de futuro quod praedicatum in propositione de praesenti stat eodem modo quo subiectum, nisi aliquid additum impediat; sed in propositione de praeterito et de futuro est variatio, quia praedicatum non tantum stat pro illis de quibus verificatur in propositione de praeterito et de futuro, quia ad hoc quod talis propositio sit vera, non sufficit quod illud de quo praedicatum verificatur, sive per verbum de praeterito sive per verbum de futuro, sit illud pro quo subiectum supponit, sed requiritur quod ipsummet praedicatum verificetur de illo pro quo subiectum supponit, secundum quod denotatur per talem propositionem.||Wherefore the difference between present tense propositions and past and future tense propositions is that the predicate in a present tense proposition stands in the same way as the subject, unless something added to it stops this; but in a past tense and a future tense proposition it varies, for the predicate does not merely stand for those things concerning which it is truly predicated in the past and future tense propositions, because in order for such a proposition to be true, it is not sufficient that that thing of which the predicate is truly predicated (whether by a verb in the present tense or in the future tense) is that which the subject denotes, although it is required that the very same predicate is truly predicated of that which the subject denotes, by means of what is asserted by such a proposition.|
|Sicut posito quod Sortes modo sit albus et fuerit per totam diem istam et non ante, tunc haec est falsa 'Sortes heri fuit albus', et tamen 'album' vere praedicatur de Sorte et similiter praedicabatur de Sorte; quia tamen heri non praedicabatur de Sorte ideo haec est modo falsa de praeterito 'Sortes heri fuit albus'.||Thus it being posited that Socrates now is white and was so for the whole day & not before, then 'Socrates was white yesterday' is false, and yet 'white' is truly predicated of Socrates and similarly was predicated of Socrates; yet because yesterday it was not predicated of Socrates the past tense proposition 'Socrates was white yesterday' is now false.|
|Similiter si Sortes nunc primo sit albus, haec est falsa 'Sortes fuit albus', et tamen Sortes fuit illud de quo modo 'album' verificatur; quia tamen haec non fuit vera 'Sortes est albus', ideo haec est modo falsa 'Sortes fuit albus'.||And similarly if Socrates is now white for the first time, 'Socrates was white' is false, and yet Socrates was that thing of which 'white' is now verified; yet because 'Socrates is white' was not true 'Socrates was white' is now false.|
|Et hoc quia praedicatum appellat suam formam, modo praeexposito; sed subiectum non sic, quia ad veritatem propositionis de praeterito non requiritur quod propositio aliqua, in qua praedicatur per verbum de praesenti praedicatum -- vel illud pro quo supponit praedicatum - de ipso subiecto, fuerit vera.||And this is because the predicate names its form, in the manner previously set out; but for the subject it is not so, because for the truth of a past tense proposition it is not required that some proposition was true, in which a predicate (or that thing which the predicate denotes) is predicated by a verb of the present tense of the subject itself.|
|Sicut si Sortes nunc primo sit albus, tunc haec est vera 'album fuit Sortes', et tamen nulla propositio de praesenti in qua praedicatur hoc praedicatum 'Sortes' -- vel illud pro quo supponit - de hoc subiecto 'album' fuit prius unquam vera, quia haec numquam fuit vera 'album est Sortes' vel 'album est hoc', demonstrando illud pro quo praedicatum supponit in ista 'album fuit Sortes'.||Thus if Socrates is now white for the first time, then 'A white thing was Socrates' is true, and yet no present tense proposition was ever true in which the predicate 'Socrates' (or what it denotes) is predicated of the subject 'white thing', because 'A white thing is Socrates' was never true, nor 'a white thing is this', referring to what the predicate denotes in 'A white thing was Socrates'.|
|Aliqua tamen propositio in qua praedicatur 'Sortes' de pronomine praecise demonstrante illud pro quo subiectum supponit in ista 'album fuit Sortes' fuit vera, nam in ista 'album fuit Sortes' li album supponit pro Sorte qui nunc est albus, et haec prius fuit vera 'hoc est Sortes', demonstrando Sortem.||Yet some proposition was true in which 'Socrates' is predicated of a pronoun referring precisely to that which the subject denotes in 'A white thing was Socrates', for in 'A white thing was Socrates', 'a white thing' denotes Socrates - who is now white, and 'this is Socrates' (referring to Socrates) was true before.|
|Ex istis patet quod haec est concedenda 'creans semper fuit Deus', quia semper propositio in qua praedicatur 'Deus' de pronomine demonstrante illud pro quo 'creans' supponit in ista 'creans semper fuit Deus' semper fuit vera, vel fuisset, si fuisset formata, nam haec semper fuit vera 'hoc est Deus'.||From these things it is clear that 'A thing which creates was always God' should be conceded, because the proposition in which 'God' is predicated (of a pronoun referring to that which 'a thing which creates' denotes in 'A thing which creates was always God') was always true (or would have been true if it had been composed), for 'this is God' was always true.|
|Haec tamen non semper fuit vera 'creans est Deus', quia ante creationem mundi fuit falsa. Sed ista 'Deus semper fuit creans' est simpliciter falsa, propter causam dictam, et ita est de multis aliis consimilibus.||Yet 'a creating thing is God' was not always true, because before the creation of the world it was false. But 'God was always a thing which creates' is absolutely false, for the reason stated, and so for many other similar propositions.|
|Et sicut dictum est de propositionibus de praeterito, ita dicendum est, proportionaliter, de propositionibus de futuro.||And what we have said for past tense propositions, should also be said, proportionately, for future tense propositions.|
THE LOGIC MUSEUM Copyright (translation) E.D.Buckner 2006