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Medieval Academy of America

John Buridan on the Objects of Demonstrative ScienceAuthor(s): T. K. Scott, Jr.Source: Speculum, Vol. 40, No. 4 (Oct., 1965), pp. 654-673Published by: Medieval Academy of AmericaStable URL: http://www.jstor.org/stable/2851403 .

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JOHN BURIDAN ON THE OBJECTS OF

DEMONSTRATIVE SCIENCE

BY T. K. SCOTT,JR

IN a recent article, Professor Ernest A. Moody has directed renewed attention

to the problem of the object of knowledge or belief (obiectum sciendi vel credendi),that so occupied philosophers in the later Middle Ages.' The problem very briefly

stated is whether the act of knowing has for its object the sentence (propositio)

known, the things designated by the terms of the sentence, or some sort of propo-sitional entity known as a complexe significabile.2 As is generally known, Ockham

initiated the debate in his commentary on the Sentences of Lombard by maintain-

ing that the proposition itself is the object of knowledge.3 As Professor Moody

shows, Ockham's position was supported at Oxford by Robert Holkot and appar-ently opposed by Walter Chatton, although it is not clear just what Chatton's

position in the dispute was. If Holkot's testimony is accepted, he certainly be-

lieved the object of knowledge to be something signified by a proposition, rather

than the proposition itself, but it is uncertain whether he is speaking of the con-

crete things designated by the terms or some other sort of entity.4On the other hand, at the University of Paris, the progress of the debate can be

traced very clearly, particularly as it applies to the knowledge supplied by the

demonstrative sciences. And it is fortunate that this aspect of the dispute can be

understood; for although the question of the objects of knowledge and belief hadimplications for theology and metaphysics, as well as for logic and the philosophyof science, its development in the Ockhamist tradition is best understood as partof a general attempt to formulate a strictly nominalistic language for science.

In this paper, I want to bring to light a discussion by John Buridan of the ques-tion of the objects known in the demonstrative sciences. Buridan's handling of

this problem would be worthy of note if only because he was the leader of the

Parisian nominalists and the most influential of those who followed Ockham. But

there are other reasons as well. In the first place, Buridan's discussion not only

involves a critique of Gregory of Rimini, whom Elie identified as the leader of theopposition to Ockham on this question, but a critique of Ockham himself. Buri-

dan's opposition to Ockham in this instance adds another dimension to the prob-lem of the objects of knowledge, and at the same time provides another exampleof a tendency toward a more stringent nominalism on the part of Ockham's fol-

E A. Moody, A Quodlibetal Question of Robert Holkot, O. P., on the Problem of the Objects of

Knowledge and of Belief, SPECULUM,XXIX(1964), 53-74. A pioneer study of the problem was

that of H. Elie, Le complexe significabile (Paris, 1936).2 Perhaps it has by now been duly noted that mediaeval philosophers used the word propositio in

the way the word 'sentence' is ordinarily used today, to designate the actual complex of terms written,spoken or thought, rather than any extra-linguistic entity expressed by the sentence. In what follows,

my use of the word 'proposition' will follow the mediaeval propositio.3 William of Ockham, Quaestionesetdecisiones in IV librossententiarum(Lyons, 1495), Book I, dist.

i2, qu. 4.4

Moody, op. cit., 59.

654



The Objectsof DemonstrativeScience 655

lowers, a tendency also exhibited by Robert Holkot.5 Secondly, Buridan considers

and rejects not only Ockham's view, but those of a number of his recent predeces-sors. Also it is of some historical interest that in treating the question, Buridan

employs a logical tool seldom found in the nominalist tradition. And finally,Buridan's own view has a number of interesting consequences for a general theoryof reference, one of which I want to mention here.

II

A major undertaking of the Ockhamist tradition was to develop a nominalistic

language for sci nce that would satisfy Aristotle's characterization of the nature

of scientific knowledge.

Now what scientific knowledge is, if we are to speak exactly and not follow mere similari-

ties, is plain from what follows. We all suppose that what we know is not even capable ofbeing otherwise; of things capable of being otherwise we do not know, when they have

passed outside our observation, whether they exist or not. Therefore the object of scien-

tific knowledge is of necessity. Therefore it is eternal; for things that are of necessity in the

unqualified sense are all eternal; and things that are eternal are ungenerated and im-

perishable.6

And a bit later, Aristotle writes:

Scientific knowledge is judgment about things that are universal and necessary, and the

conclusions of demonstration, and all scientific knowledge, follow from first principles

(for scientific knowledge involves apprehension of a rational ground).7

A problem for the Ockhamist is to determine how to meet the requirements of

universality, necessity, and eternity for objects of science, while maintaining that

reality is composed solely of concrete contingent particular entities. Ockham's

view that the object of knowledge is the proposition alone contains an implicit

solution to this problem. For he can say that although all knowledge begins in

intuitive cognition of particular things, the immediate object of knowledge is only

the proposition itself, and the requirements of eternity and necessity are met by

our knowing the proposition to be true at any time.

It is well known that Gregoryof Rirnini

opposedOckham's

general positionon

the objects of knowledge. Gregory's argument is that although a proposition is

formed in the act of knowing, what is known is not the proposition, but what the

proposition signifies.8 To know a fact is not at the same time to know any proposi-

6 Ibid., p. 69. Ilolkot criticizes Ockham for identifying a proposition with what is now known as a

type-sentence, rather than a token-sentence. For Holkot, a proposition is just a group of sounds or

marks, so that every time a syntactically acceptable group of marks is made, a new proposition is

created. Ockham's view that identical tokens are the same proposition seems to Holkot a concession

to Platonism. That Buridan agrees with Holkot will be seen below.

6 NichomacheanEthics (W. D. Ross translation), vI, 6, 1139b 19-24.

7 Ibid., vi, 6, 1140b 30-33.8 Gregory of Rimini, Super Primumn t SecundumSententiarum(St Bonaventure, 1955 reprint of

the 1522 Venice edition), T,pro., qu. 1: Si obiectum scientiae esset ipsa conclusio, sequeretur quod qui-

libet actu sciens scientia acquisita per demonstrationem, actu apprehenderet conclusionem suae

demonstrationis. Hoc patet, sed consequens probatur esse falsum per experientiam. Nam plerumque,

immo quasi semper, contingit quod demonstrans, quamvis formet conclusionem, non tamen actu re-

flectitur super illam apprehendendo ipsam, sed directe figit suum aspectum in id quid ipsa significat.



656 The Objectsof DemonstrativeScience

tion to be true, for these are distinct acts.9 In fact, in the act of knowing that the

sides of a triangle are equal, a geometer does not likely have in mind the truth of

any proposition at all, and when a doctor knows to prescribe a certain medicine,

he is not thinking of propositions, but of facts.10

Gregory concludes, therefore, that the object of knowledge must be something

signified by the proposition. But he also argues that it cannot be the things desig-nated by the terms of the proposition, and his reason for rejecting this view is

interesting. For he does not argue, as Holkot does, that particular things cannot

be the objects, since the object of knowledge must be true, and particular thingscannot be true. Rather, Gregory cites Aristotle's remark that the objects of

knowledge are eternal and of necessity. Now only God meets this requirement, so

that no contingent particulars can be objects of knowledge.ll

Gregory's own view is that the object of knowledge is the significatum totaleconclusionis.12This significate is not a contingent particular thing, but neither is it

a universal nature, for it is not an existent thing at all. It is a subsistent, inten-

sional entity, a complexesignificabile.13And this significate meets all requirementsfor an object of knowledge. In the first place, it is true and is opposed to a false

contradictory significate, so that it satisfies the definition of scientia as knowledgeof what is true.l4 And at the same time, the complexe significabile is of necessityand it is eternal, so that necessary knowledge is not grounded in contingent exis-

tence.l5

9 Ibid.: aliud est quaerere utrum latera huius trianguli sint aequalia, et aliud utrum haec propositio'Latera huius trianguli sunt aequalia' sit vera.

10Ibid.: Unde nec geometer demonstrans latera trianguli descripti secundum doctrinam primaeconclusionis primi Euclidis esse aequalia considerat vel apprehendit quod conclusio qua enuntiat illa

esse aequalia est vera; nec medicus concludens tali morbo talem debere dari medicinam cogitat quodsua conclusio est vera, quamvis uterque hoc facillime posset.

11 bid.: Nam ut ait Philosophus sexto Ethicorum, omnes suspicamur quid scimus non contingerealiter se habere, et ex hoc concludit quod scibile est aeternum et ex necessitate.... Si vero res extra

sint obiecta scientiarum, multae scientiae, et physicae et geometricae et aliae plures, essent de rebus

aliis a Deo et contingentibus. For Ilolkot's view, see the Question edited by Moody, Op. cit., p. 59,

line 14.12 Ibid.: Probo quia vel obiectum scientiae totale est conclusio, vel tota demonstratio, vel res extra,

vel significatum totale conclusionis seu significata totalia praemissarum et conclusionis. Sed non con-

clusio, ut prius probatum est, nec etiam tota demonstratio, sicut eiusdem probari potest, nec etiam res

extra, ut patet ex secunda conclusione, nec significata omnium propositionum demonstrationis, quiaut infra patebit, non eodem actu omnia cognoscunt; igitur significatum totale conclusionis.

13 Ibid.: dicendum quod hoc nomine 'aliquid,' sicut et ista alia sibi synonyma 'ens' et 'res,' possunt

accipi tripliciter. Uno modo communissime, scilicet quod omne significabile complexe vel incomplexe,et hoc vere vel false, dicit res et aliquid.... Alio modo sumuntur pro omni significabili complexe vel

incomplexe sed vere, id est per veram enuntiationem.... Tertio modo sumuntur ista ut significant

aliquam essentiam sive entitatem existentem, et hoc modo quid non existit dicitur nihil.... Nunc ad

argumentum cum dicitur utrum istud totale significatum sit aliquid vel nihil, dico quod si 'aliquid'sumatur primo modo vel secundo modo, est aliquid; si vero tertio modo sumatur, non est aliquid.

14 Ibid.: non solum enuntiationes ipse dicuntur verae vel falsae, sed earum enuntiabilia seu signifi-cata adequata, licet in alio et alio sensu. The sense in which it is true turns out to be as the significateof a true proposition.

15 Gregory knows, of course, that no existent thing other than God is eternal. But there is a specialsense in which the significate is eternal. Ibid.: Sed ideo dicuntur esse de necessariis, quia ea quae



The Objectsof DemonstrativeScience

It is not certain that Ockham was familiar with a position exactly like that of

Gregory, although this may have been Chatton's view. But it is likely that he

would have rejected the complexe significabile, since it was his bent to eliminate

not merely universals, but all abstract entities of whatever sort. However, in

rejecting the complexe significabile and holding that concrete existents are the

only real things, Ockham still must meet Gregory's second argument that neces-

sary truth cannot be grounded in a world of contingent existents. He must still

explain the relation between the truths of demonstrative science and the world of

temporally located individuals. For this is also a part of the problem of the objectsof knowledge.

Ockham does provide such an explanation, but it was an explanation that

Buridan regarded as weakening Ockham's general position and as based on an

abandonment of genuinely Ockhamist principles. But this can be better under-

stood in the light of a few general remarks on the mediaeval theory of reference

and its importance for the nominalists.

III

As a general program in the philosophy of knowledge, mediaeval nominalism

had two primary objectives. One of these was, of course, the exorcism of all ab-

stract entities of whatever sort, and the establishment of concrete particulars as

the only proper claimants to existence. But this was a largely negative under-

taking, and once it was complete a more important task remained. This was the

second objective, of grounding knowledge in the world of concrete particulars.

Specifically, it was necessary to explain in detail the relationship between a lan-

guage that depended heavily on abstract general terms and a world composed

wholly of concrete things.This latter objective was crucial to the nominalist program. Because from the

point of view of knowledge, Ockham's elimination of abstractions was due to his

concern to establish the objectivity of knowledge, by emphasizing the priority of

concrete being to cognitive activity. And the most marked characteristic of the

Ockhamist mentality was its emphasis on the primacy of being. All human knowl-

edge has its origin in direct intuitive cognition of concrete beings, and all general

knowledge is ultimately knowledge of particular beings.In order to achieve this end, nominalist logicians took the terminist logic that

had developed out of the SummulaeLogicales of Peter of Spain and interpreted it

in such a way that it reflected the dependence of knowledge on the world of par-ticular beings. As they understood the matter, this required two things of them:

(1) to show that the meaning of any proposition containing general terms can be

wholly explicated by means of propositions containing only singular terms; (2) to

show that the truth of every proposition containing general terms is wholly de-

pendent on the reference of its terms to particular existents.

sciuntur non contingit non sic esse .... Et eodem modo cetera scibilia quae propria scibilia dicuntur,

ut pote quae sunt significate conclusionum syllogismorum demonstratorum, intelligi debent necessaria

et aeterna, et similiter obiecta propositionum aliarum necessarium.

657




The first of these requirements was met by devising a complex set of rules for

establishing equivalences between quantified propositions and conjunctions or

disjunctions of propositions containing no quantifiers and only singular terms.

These rules, governing what is often known as the reduction to singulars, are aningenious and little understood part of terminist logic.16

The second requirement, which is of more direct concern for present purposes,was met by a general theory of reference (suppositio), and in particular by varia-

tions on a general rule stating that a categorical proposition is true if, and only if,its subject and predicate terms stand for (supponunt pro) the same particularentities.l7 Thus the truth of a proposition is determined altogether by its reference

to particulars.The situation was complicated, however, by the mediaeval use of the word

propositio. As was mentioned above, terminist logicians used the word proposi-tion in the way the word sentence is ordinarily used today, to designate a sort

of language expression, rather than something expressed by a linguistic complex.l8Furthermore, propositions were typically regarded not only as what we call sen-

tences, but as what Quine has called occasion sentences, as opposed to standingsentences.l9 That is, the content of the proposition was regarded as dependent on

the time at which the proposition was written or uttered. Every proposition was

token-reflexive, in the sense that it contained an implicit reference to the time of

its occurrence. Thus a proposition such as Socrates is sitting depends for its

truth on whether Socrates is indeed sitting at the time the proposition is written or

spoken. This means, of course, that a proposition may be true at one time and

false at another, since Socrates may be sitting now, only to rise at a later time.

In order to account for the time-dependence of truth-values in terms of the

theory of reference, mediaeval logicians introduced a number of rules for the

extension and restriction (ampliatio et restrictio) of suppositio.20The reference of

16These rules were treated as governing divisions of suppositio personalis. But it can be seen easilythat these rules do not effect types of reference, as do other rules of suppositio, but are concerned with

the interpretation of propositions. For Ockham's rules, see his Summa Logicae: Pars Prima, ed. by P.

Boehner (St Bonaventure, 1957), Chs. 70-74. Much the same rules are found in Buridan, Perutilecompendiumtotius logicaeJohannis Buridani (Lyons, 1499), Tract Iv.

17As an example, I quote Ockhamu'sule for the truth of singular propositions, but it applies with

slight variations to other types. Summa Logicae: Pars Secunda et Tertiae Prima, ed. by P. Boehner

(St Bonaventure, 1954), ii, Ch. 2: Dicendum est quod ad veritatem talis propositionis singularis, quae

non aequivalet multis propositionibus, non requiritur, quod subiecturn et praedicatum sint idem

realiter, nec quod praedicatum ex parte rei sit in subiecto, vel insit realiter ipsi subiecto, nec quod uni-

atur a parte rei extra animam ipsi subiecto - sicut ad veritatem istius: 'Iste est angelus,' non re-

quiritur, quod hoc commune 'angelus' sit idem realiter cum hoc, quod ponitur a parte subiecti, nec

quod insit illi realiter, nec aliquid tale -, sed sufficit et requiritur, quod subiectum et praedicatum

supponant pro eodem. For Buridan's similar discussion of truth-conditions, see SophismataBuridani

(Ms Erfurt Ampl. F302, fols. 155-191), Ch. 2. The best discussion of mediaeval theories of truth is tobe found in E. A. Moody, Truthand Consequencen MediaevalLogic (Amsterdam, 1953), Ch. 3.

18Supra, note 2.

19W. V. Quine, Wordand Object Cambridge, 1960), pp. 35-36.20For Buridan's rules, see Perutile compendium totius logicae, Tract iv. Ockham does not treat

ampliatio in isolation, but many examples of his use of the doctrine can be found. See e.g. Summa

Logicae, ii, Ch. 7.

658




any term is determined by the tense of the proposition in which it occurs. Thus in

the proposition Some men are Greeks, the term men refers only to men exist-

ing at the time the proposition occurs, whereas in the proposition Some men were

Greeks, the same term refers both to presently existing men and to those whoexisted at all times before the occurrence of the proposition. Reference is alwaysto some particular individuals existing at some particular time, and the rule for

truth must be interpreted in such a way that a proposition is true if its terms refer

to the same things and false if its terms refer to different things or if one of its

termsrefersto nothing.2'For example, the proposition Some men are Greeks is

false if all existing men are non-Greeks, but it is also false if there happen to exist

no men at the time the proposition occurs.

This temporal reflexivity led to some difficulty in the case of the propositions of

demonstrative science. For these propositions are necessary, that is, they are trueat all possible times. And yet these propositions are typically framed as categori-cal propositions of present tense (e.g. Every triangle has three angles or Everyman is an animal ). And according to the usual rules for truth, a proposition such

as Every triangle has three angles must be false if no triangles happen to exist

at the time the proposition is uttered, and a proposition such as Every man is an

animal must certainly have been false prior to the sixth day of creation. The

integrity of demonstrative science thus required that the necessity of demonstra-

tive principles and demonstrated conclusions be protected from the contingencies

of existence. This is the problem that Gregory of Rimini poses in asking how the

necessity of science is to be grounded in contingent particulars.Ockham recognized this problem, but his solution seemed to Buridan an abdica-

tion of the principle that knowledge is to be objectively grounded in particularexistents. For Ockham thought that if the truth of scientific propositions is made

dependent on particulars, even in the sense that the proposition asserts that its

subject and predicate terms stand for the same things, then the necessity of these

propositions is lost. But he also thought that since every categorical propositiondoes so depend on contingent existence, every categorical proposition must be

contingent. For this reason, he held that affirmative scientific propositions mustbe regardedas disguised hypotheticals, even if they have the form of categoricals.A proposition such as Every man is an animal should be understood to assert

only that if anything is a man, then it is an animal.22No assertion about the exis-

21Cf. Buridan, Sophismata, Ch. 2, conclusion 10: ad veritatem cathegoricae affirmativae requiritur

quod termini, scilicet subiectum et praedicatum supponant pro eodem vel eisdem. Ideo etiam ad eius

falsitatem sufficit quod non supponant pro eodem vel eisdem. And as an example, see the reply to the

fourth sophisma of Ch. 2: dicitur quod haec est false: 'Vacuum est locus non repletus corpore,' quiatermini pro nullo supponunt.

22 Ockham, Logica (Bologna, 1498), II, 2, Ch. 5: Ex quo patet quod quamvis repugnat dictis

Aristotelis, tamen secundum rei veritatem, nulla propositio, quae importat res corruptibiles, mere af-

firmativa, mere cathegorica et mere de praesenti potest esse principium demonstrationis vel conclusio,

quia quaelibet talis est contingens. Si enim aliqua talis esset necessaria, hoc maxime videret de tali

'Homo est animal rationale.' Sed haec est contingens, quia sequitur: homo est animal rationale mor-

tale, ergo homo est animal, et ultra, ergo componitur ex corpore et anima intellectiva. Sed haec est

contingens, quia si nullus homo esset, ipsa esset falsa, propter falsam implicationem. Quia implicatur

659




tence of any particular men is involved, so that this proposition can be regardedas true independently of the state of the world at any given time. If it happensthat some men do exist at the time the proposition is uttered, it may be said that

such a proposition provides reference to those men.23But it is also the case that ifno men exist, the proposition is still true, although its terms referto nothing at all.

Buridan's objection to Ockham's position sterns from his insistence that the

terms of every proposition refer to determinate things, in particular his insistence

that there can be scientific knowledge of non-existents. I want now to turn to

Buridan's development of his own view.

IV

In the years around 1320, when Ockham initiated the debate over the object of

knowledge in his commentary on the Sentences, Buridan had probably alreadybegun his career at Paris. And certainly by 1344, when Gregory of Rimini lectured

on the Sentencesand opposed Ockham, Buridan was an important figure, havingbeen twice Rector of the University. In fact it was during his tenure as Rector in

1340 that certain propositions usually ascribed to Nicholas of Autrecourt were

condemned by the Parisian Faculty of Arts. Some of these propositions seem

clearly to reflect the opinion that a proposition has for its object an abstract inten-

aliquid componi ex corpore et anima intellectiva, quod tunc foret falsum. ... Et ideo dico quod nullatalis potest esse principium vel conclusio demonstrationis. Hoc tamen non obstante dicendum est

quod multae propositiones compositae ex talibus terminis possunt esse principiis vel conclusiones

demonstrationis, quia propositiones conditionales vel aequivalentes eis possunt esse necessariae. Haec

enim est necessaria simpliciter; 'Si homo est, animal est'.... Ex isto etiam patet quomodo de con-

tingentibus potest esse scientia, quia secundurn quod veniunt in demonstrationem sunt necessariae,hoc est quod propositiones formatae ex terminis importantibus talia contingentia quae veniunt in

demonstrationem sunt necessariae, quae non sunt mere de praesenti et de inesse, cathegoricae et

affirmativae, sed vel sunt negativae vel hypotheticae vel de possibili, vel aliquo eis aequivalentes. In

what follows, I shall be discussing primarily propositions considered as hypothetical. The other two

cases are less interesting. The truth of a negative proposition requires only that the terms not stand

for the same things, so that if one of them stands for nothing the proposition is trivially true (Cf.Summa Logicae, ii, Ch. 3). And in a proposition of possibility (in sensu diviso), the subject term stands

for all possible designata -present, past, and future - so that such a proposition does not depend

for reference on what exists at any time (Cf. Summa Logicae, ii, Ch. 10). Buridan does not object to

either of these cases. Indeed in his Questionessuper octo phisicorum libros Aristotelis (Paris, 1509),Book I, qu. 1, the only scientific propositions discussed are those of possibility whose predicates end in

-ibile and so significant omnesres et supponunt pro omnibus rebus. But Ockham himself does not pro-

pose either the negative or the modal as a general form for scientific propositions. The negative form

clearly cannot so serve; and as for the modal form, even in an Aristotelian science of natures and

their dispositions, it would prove awkward to translate every assertoric categorical into a propositionof possibility. On the other hand, translation into hypothetical form is easily carried out in every case,

so that Buridan's special attention to this tactic is justified.23 It is in this sense alone that one can understand Ockham's contention that science is of proposi-

tions whose terms refer to existent things. Cf. Expositio super libros Physicorum (Prologue ed. byG. M. Mohan in Franciscan Studies, xxvi (1945), 235-246), 243: Tamen metaphorice et improprie

loquendo, dicitur Scientia Naturalis esse de corruptibilibus et mobilibus, quia est de illis terminis qui

pro talibus supponunt. For it is quite clear that science may be of propositions whose terms stand for

nothing at all.




sional entity or significate, a complexesignificabile.24And there can be no doubt

that Buridan personally opposed this view, for in his Sophismata, he attacks it in

some detail. He holds that everything is a complexesignificabile, in the sense that

it can be signified in a complex manner, i.e. by a complex of terms.25But he deniesany entity such as Gregory speaks of. In particular, he rejects the view that the

proposition God is not signifies some entity such as God-not-being (Deum non

esse), for there just is no such entity.26What is signified by a proposition is neither

the proposition itself nor anything expressed by an accusativus cum infinitivo, but

rather the singular things for which the terms stand.27

Buridan agrees with Ockham that the proposition itself is the immediate objectof knowledge. He also insists that it is proper to say that concrete things are ob-

jects of knowledge, since to know a proposition is also to know something about

particular existents.28 But he means this in a much stronger sense than Ockham,for he will insist that no proposition can be known to be true if its terms are with-

out definite referents. It is his insistence on the transparency of the proposition in

knowing concrete existents that leads him to reject Ockham's view of the proposi-tions of demonstrative science. For it seemed to him that if scientific propositions

may be true even though their terms refer to nothing at all, then in knowing such

a proposition to be true, one cannot be said to have knowledge of any particular

things. Already in his Sophismata, he complains about those who say that we

have knowledge only of the demonstrated conclusions and not of other things,

24See Chartularium Universitatis Parisiensis, ed. by Denifle and Chatelain (Paris, 1889-1897), II,

578. Concerning the influence of Gregory of Rimini on Nicholas of Autrecourt, see H. Elie, Op. cit.,

pp. 37-40 and also J. R. O'Donnell, The Philosophy of Nicholas of Autrecourt and His Appraisal of

Aristotle, MediaevalStudies, iv (1942), 97-125. For more on this controversy and Buridan's part in

it, see E. A. Moody, Ockham, Buridan and Nicholas of Autrecourt, Franciscan Studies, vII (1947),113-146.

25Sophismata, Ch. 1, response to the fifth sophisma: immo omnia entia de mundo sunt complexe

significabilia, etiam omne ens quantumcumque simplex est complexe significabile. Verbi gratia, Deus

qui est summe simplex significatur complexe per hanc orationem 'Deus est Deus'.... The sophism

being responded to is 'Complexe significabilia sunt chimerae.'

26 Ibid.: Et etiam concedo quod ista oratio 'Deus non est' non significat Deum non esse, quia Deumnon esse nihil est, nec erit, nec potest esse

27 Ibid.: Dico quod Sortem diligere Deum est Sortes, si Sortes diligit Deum, sed si Sortes non diligit

Deum, tunc dico quod Sortem diligereDeum nihil est.`3Questionessuper octophisicorum libros Aristotelis, Book i, qu. 1 (The Question is Utrum scientia

naturalis sit scientia de omnibus rebus): Tertia conclusio: quod quarto modo scientia naturalis con-

siderat vel est de omnibus rebus, scilicet tanquam de significatis per terminos conclusionum et prae-missarum quarum et per quas ipsa est demonstrativa. And a few lines later, he speaks directly to the

matter of necessity and contingent being: Ad rationes principalis dicendum est quod quando dicunt

phisici nulla esse scientiam nisi de veris et necessariis, ipsi intendunt de his quae sciuntur tanquam

conclusiones demonstrabiles, vel demonstratae. Non enim sunt conclusiones demonstrabiles vel deIn-

onstratae nisi sint verae et contingentia eodemmodo quo haec nomina solent appropriate attribui

propositionibus. Sic enim intendunt phisici quando dicunt quod non est scientia de entibus per acci-

dens. In sic loquendo non intendunt nisi propositiones contingentes et per 'entia per se' propositionesnecessarias. ... Quando etiam dicitur quod non est scientia de singularibus, intelligendum est quod

propositiones singulares non sunt demonstrabiles.... Res tamen omnes singulares singulariter

existentes sciuntur tanquam per terminos, termini enim universales significant res singulariter ex-

istentes.

661




such as stones and animals and such. This cannot be accepted, according to

Buridan, for then it follows that although a physician knows many propositionsabout diseases to be true, still he has no knowledge of any particular disease, and

even though one may know propositions about God to be true, one remains

wholly ignorant of God.2

It is perhaps not obvious that this criticism is directed at Ockham's position,but in another discussion, Buridan makes it quite clear that he does indeed opposeOckham. In his Questions on Aristotle's Ethics, he criticizes Ockham's position

along with several others, and develops his own more strictly nominalistic view.

The context for the discussion is provided by Question 6 of Book vi - Whether

everything knowable is eternal (Utrum omne scibile sit aeternum).30Althoughthis is not an ethical question, its occurrence is natural, since it is in Book vi of the

Nicomachean Ethics that Aristotle characterizes scientific knowledge as being ofthe universal, necessary and eternal. And it seems very likely that the Questionwas occasioned by Gregory's rejection of concrete things as entities of knowledge,on the ground that what is known must be eternal.

V

Buridan begins his consideration of the Question Whether everything know-

able is eternal by making clear his position in the dispute over the objects of

knowledge and belief. For he says that knowable (scibile) can be understood in

two senses. It may be understood to stand for the conclusion of a demonstration,which is the immediate object of knowledge, or for the designata of the terms of

the conclusion. That is to say that he agrees with Ockham that the immediate

object of knowledge is the proposition, but he wants it understood that it is also

acceptable to speak of scientia as having concrete objects as its objects.

Sciendum st quod scibile'potestcapi dupliciter: nomodoproconclusione emonstrabili;alio modopro re significatavel rebussignificatisper terminosconclusionis, ive pro qua,vel pro quibus terminiconclusionis upponunt.Haec enim conclusio'Omnishomo estrisibilis' st scibilisquiademonstrabilis,t sciendoeam nos habemus cientiamde omnibus

hominibuset de omnibusrisibilibus.31

He then proceeds to examine each of these possible objects of knowledge, inorder to determine in what sense it is or is not proper to say that the object of

knowledge is eternal. He considers first the proposition as an object of knowledge,and his remarks make it obvious that he agrees with Holkot's extremely nomi-nalistic characterization of a proposition as merely a sentence token.32For he says

29Sophismata, Ch. 4, response to the thirteenth sophisma: Dixerunt quidam quod de solis conclu-

sionibus demonstratis habemus scientiam, et non de rebus aliis, ut nec de lapidibus, animalibus, et sic

de aliis. ... Et tunc etiam ... sequeretur quod licet haberem scientiam de Deo, de caelo, de animal-

ibus, de sanitate vel egritudine, tamen de caelo nullam haberem scientiam, nec de Deo, nec de ani-

malibus, nec medicus de sanitate vel egritudine haberet scientiam. Et hoc apparet duram concedere.30I want to thank Professor James J. Walsh for having called this Question to my attention.31 The source for all quotations of this section, unless otherwise noted, is Joannis Buridani ques-

tiones libri Ethicorum(BN Ms. Lat. 16128), which dates from the fourteenth century.32 Cf. supra, note 4.

662




that if we interpret the question as asking whether a proposition exists eternally,our answer must clearly be negative, since a proposition is no more eternal than

any other physical entity. But on the other hand, if the question is interpreted as

inquiring after the truth of a proposition, then we can say that although no propo-sition is true unless it exists, it is the case that the conclusions of demonstrative

science are necessarily true when they do exist.

Si igitur quaestio quaerat de scibili pro conclusione demonstrabili, tune iterum erit dis-

tinguendumn;quoniam vel 'conclusio' sumitur quantum ad suam realitatem, vel quantumad suam veritatem. Si quantum ad suam realitatem, tune nulla conclusio debet diciaeterna vel necessaria plusquam asini aut equi aut colores vel sapores. Quia conclusionesde novo formamus tam in scripto, quam in voce vel in mente, et ita incipiunt esse etdesinunt esse, sicut colores aut sapores. Si 'vero conclusio' capiatur quoad eius veritatem,tune potest ad huc intelligi dupliciter quod conclusio sit aeterna, sit necessaria, impossibilisaliter se habere. Uno modo, quod conclusio sit semper vera, loquendo categorice etsimpliciter; et isto modo conclusio non est magis necessaria vel aeterna quoad eius veri-tatem quam quoad eius realitatem. Quia quandocumque ipsa non est, ipsa non est vera.Alio modo, loquendo hypothetice, quia scilicet omnis talis conclusio sit vera quaecumqueproponitur, ita quod non possit esse falsa. Et isto modo vel in aequipollenti sensu proposi-tiones dicuntur necessariae, perpetuae vel impossibiles aliter se habere, et non alio modo,sive sint propositiones scriptae sive prolatae vel apud mentem nostram formatae.

It is concluded, then, that the propositions of demlonstrative science, unlike

those of mere opinion, are true whenever they occur. But this brings Buridan to a

more important problem. For how can these propositions be necessarily true,unless the objects known by the propositions are themselves eternal? The relation

between necessary truth and contingent existence is obviously a matter of first

importance, and Burdian considers five possible solutions to the problem, before

stating his own.

(1) The first opinion considered follows from the view that essence and exis-

tence are distinct in created things, and that essence is eternal. It can then be held

that scientific propositions refer only to essences, not to particular beings, so that

we can be sure that the objects of knowledge are indee(d eternal.33

Una (opinio) est distinguens inter esse et essentiam. Vidimus enim quod nomina etdefinitiones significant essentias rerum, quae tamen non significant res esse nec non esse,ut habetur in libro Posteriorum. Ponit autem haec opinio res aeternaliter permaneresecundum suas essentias, sive secundum quidditates suas, licet quantum ad esse non

maneant. Essentiae vero rerum, ut dicunt, manentes eadem, recipiunt esse per genera-

33Stated in just this way, the view is not easy to identify. The reference may be to Henry of Ghent.

Cf. SuimmaeQuaestionumOrdinariarum Theologi . . Henrici a Gandavo .. (Paris, 1520), Art. IIm,

qu. 1: Possibile est te intelligere hominem simpliciter, ita quod non intelligas an habeat esse extra, an

non esse, sicut an habeat esse album, an non. Et si dubitas forte an habeat esse in mundo, an non, hoc

non impedit tuum intellectum ad intelligendum essentiam hominis. Concerning the sort of being that

Henry regards as an esse essentiae, see QuodibetaMagistri Henrici Goethalsa Gandavo(Paris, 1581),

Quodlib. II, qu. 9: Unde cum illud quid habet exemplar in Deo non potest ipsum non habere, quicquidin certitudine sua essentia est et res aliqua, necesse est ipsum esse tale, et non potest non esse tale, et

habere esse essentiae, et non potest non habere solum in intellectu tamen saltem divino. Sic habent

omnia facta et factibilia ab aeterno, velin intellectuvelin rebus extra. (Italics mine). But this is some-

what misleading, for Henry's distinction between esse and essentia is rather subtle, since the esse of

something is its essentia when it is actual.




tionem et amittunt esse per corruptionem.... Dicunt igitur isti quod sicut res sunt

scibiles, ita sunt aeternae. Si enim sint scibiles quantum ad essentiam solum, non oportetquod sint aeternae quantum ad esse rei.34

Buridan rejects this view, primarily because he refuses to recognize an essence

as anything other than just the being of which it is the essence. More precisely, his

position is that the term essence (essentia), like all abstract terms, is no more

than just a term formed from a concrete term, in this case the term being (esse)- so that it cannot be taken to have any content other than that of the concrete

term from which it is formed. Just as whiteness has no content beyond white

things, so essence has no content beyond concrete beings. To speak of an es-

sence is to speak of a being, so that it is contradictory to speak of an essence which

is not a being.

Ista opinio non placet mihi. Primo quia non puto quod esse et essentia distinguanturin ipsa re praeter animam, quod videri debet quarto Metaphysicae. Secundo quia peri-culosum mihi videtur in fide dicere aliquam rem esse aeternam quae non sit Deus. Tertio

quia videtur mihi implicare contradictionem quod essentia maneat et non esse, quia quodmanet est et habet esse. Quarto quia si essentia manens suscipit esse et non esse, non

oportebit aliam ponere materiam, quia illa essentia poterit deferre transmutationem etterminos transmutationis, cum ipsa maneat eadem. Quinto quia videtur mihi, quod hocnomen 'essentia' non est nisi abstractum huius concreti 'esse,' sicut 'entitas' huius concreti

'ens' et 'quidditas' huius concreti 'quid' et 'realitas' huius concreti 'res.' Ideo sicut resdicitur albedine alba, ita dicitur essentia esse et entitate ens et quidditate quid vel aliquid.35

(2) A second view, specifically attributed to Giles of Rome, is that one can

speak of the being of things in three ways. Things may be said to be in the mind,

since we have ideas of them. Or they may be said to be in their causes, since their

causes fully account for their being. Or finally, they may be said to be in actuality,as effects of their causes, i.e. as the concrete things produced. According to Giles,the demonstrative sciences are concerned only with the causes of things and so

deal with their being in that sense alone. And since causes can be considered apartfrom any particular effect, we may say that the demonstrative sciences are inde-

pendentof

temporalexistence and that their

objectsare eternal.36

Aegidius autem, super librum De Generatione,distinxit triplex esse rerum, scilicet in

anima, in suis causis et in effectu seu in esse producto. Dicit ergo quod scientia, cum habe-atur de rebus per suas causas, non habetur de rebus quantum ad suum esse in effectu, sed

34 The Aristotle reference is to PosteriorAnalytics, ii, 7, 92b 18-29.35The reference is probably to Aristotle, Metaphysics, iv, 2, 1003b 27-30. The fourth objection is

not clear. Possibly Buridan is identifying essence with form, in which case it might account for sub-

stantial change. But if essence is identified with the composite of matter and form, as was usual, it is

not easy to see the point, since it would not then account for change.

36

Giles of Rome, Quaestionessuper libris Aristotelis de generationeet corruptione (Venice, 1500),Book I, qu. 1: est videre quomodo manet scientia re corrupta. Ad cuius evidentiam notandum quod res

habent tripliciter esse - in se ipsum, in suis causis et apud intellectum.... Est autem ulterius diligen-ter notandum quod existentia rei in suis causis facit ut de re possit esse scientia, non solum ut per cog-nitionem causae cognoscitur effectus, sed quam sufficit ad rationes quidditatis quod sit in potentia ad

esse. Res ergo quia eo ipso quod sunt in causis sunt in potentia ad esse et eo ipso quod sunt in suis

causis, competit eis habere quidditatem. Et quia quicquid est est obiectum intellectus, ideo quae suntin causis suis possunt sciri et possunt esse obiectum intellectus.




quantum ad esse quod habent in suis causis; propter quod ipse concedit res scibiles esseaeternas pro esse quod habent in suis causis, sed non oportet eas esse aeternas pro esse suoin effectu.

Buridan thinks it simply false that we have knowledge only of causes and not of

effects. If I know that thunder is a sound in the clouds, then I have knowledge of

thunder, not merely of what causes thunder. Furthermore, he holds that it is

misleading to speak of the being that a thing has in its causes, as distinct from its

being as an effect. The causes of a thing are the conditions of its existence. When

these conditions are met, the thing is, and until they are met, the thing simply is

not. To say that it has potential being before it actually exists is just to say that it

is not, although it might be if certain conditions were met. There is only one sort

of being, and that is the being of concrete existents, only one of which is eternal,

and He is not an object of knowledge at all.

From the point of view of science, this means that knowledge is always and

only of a concrete and actual being, in so far as it is of a being at all. If I know the

being of the causes of a thing, that can only be because the conditions for its exis-

tence are met, in which case I know the thing itself. If the thing does not exist,

that can only be because the conditions for its existence do not themselves all exist,

so that if I do not have knowledge of the being as an effect, I do not have knowl-

edge of any being. To say that I know a thing as it is in its causes, but not as it is

in its effects is just to say that I do not know what is in any sense, but only what

might be.

Sed nec ista opinio placet mihi, quia non est verum quod scientia non habeatur de rebus proesse suo in effectu, quia tune effectus non scireturper suas causas, quoniam esse quod habeteffectus in causis prout distinguitur ab esse in effectu non est, ut puto, nisi per esse cau-saram. Ideo non sciretur nisi esse causarum. Item scio per librum Meteorumquod tonitruest sonus factus in nubibus et quod pluvia est aqua in nubibus guttatim cadens. Haecautem non sunt vera, nisi quantum ad esse pluviae et tonitrui in effectu. Item res esse quodhabent in causis, distinctum ab esse quod habent in effectu, non habent nisi in potentia.Igitur res non sciretur nisi quantum ad esse potentiale et non actuale. Item si res essentscibiles solum per esse quod habent in causis et ita aeternae, vel hoc esset per esse quod

habent in causis sufficientibus vel in causis non sufficientibus. Si non sufficientibus, se-queretur quod non posset scientia perfecta de eis haberi; si sufficientibus, tune etiam essentaeternae pro esse in effectu, quia positis causis sufficientibus ponitur effectus. Item formaest una causa et principalis causa. Ideo oportet rem scibilem secundum istos esse aeternam

pro esse quod habet in causa formali, quod non esset nisi causa formalis sit aeterna. Ettamen si sit aeterna, effectus est aeternus. Illa igitur opinio multipliciter deficere videtur.

(3) The next position is that of a logical realist, who holds that universals are

really distinct from particulars and so remain always the same as objects of

knowledge, even if particulars are corrupted.37

37 This view might have belonged to any good Augustinian or Scotist, but its inspiration is likely in

passages such as the following from Duns Scotus, Opus Oxoniense, i, dist. iii, qu. 4 (included in Duns

Scotus:Philosophical Writings, ed. by A. Wolter (Edinburgh, 1962)): Non sequitur etiam: si objectumest mutabile, igitur quod gignitur ab eo non est repraesentativum alicujus sub ratione immutabilis,

quia mutabilitas in objecto non est ratio gignendi, sed natura ipsius objecti, quod est mutabile, vel

quae natura est immutabilis.




Alii distingunt inter universale et singulare, non solum secundum conceptum, sed in re

extra, in tantum quod dicunt universale pro re extra nec esse generabile nec corruptibile.Singulariaautem dicunt esse generabilia et corruptibilia. Dicunt igitur non de singularibus,

sed de universalibus esse scientiam, et ita scibilia dicunt esse perpetuas, licet eorum singu-laria sint perpetua corruptibilia.

Of course, Buridan rejects this on the general ground of his nominalism. But he

also adds that even if universals are separate from particulars, they could not be

expected to survive the destruction of all particulars, although they are indepen-dent of the existence of any one particular. But science is possible even if all par-ticulars are destroyed, since I can have a science of astronomy, even if all heav-

enly bodies are destroyed, and I can know about thunder on fair days as well as

stormy ones.

Sed ego puto quod universale non sit praeter animam distinctum a singularibus, quod ad

praesens suppono ex septimo Metaphysicae. Et si esset distinctum, tamen nisi esset idea

separata, non posset manere omnibus eius singularibus corruptis. Et tamen notum est, utmihi videtur, quod si omnes rosae nunc essent corruptae, sic quod nullo modo essent; velmodo si nulla sint tonitrua, nullae stellae comatae aut nullae eclipses solis aut lunae; tamenmedicus ob hoc non amitteret scientiam quam habet de rosa, nec astrologus scientiam

quam habet de eclipsibus, nec tu scientiam quam tu habes de libro Meteorumde tonitruis etstellis comatis. Immo tu posses me docere scientiam libri Meteorurm,icut si essent milletonitrua. Ideo talis distinctio de universali et singulari pro re, si concederetur, tamen nonvaleret ad propositum.38

(4) The next view Buridan attributes to Aristotle and Averroes, although it

might as easily belong to Thomas Aquinas. It is based on a view, according to

which there are no universals apart from individuals, except in the mind. But

there is a succession of beings, so that scientific propositions have reference at anytime. For so long as any member of a species exists, the propositions of science can

refer to that member, so their necessity is guaranteed.39

Alii autem ponentes universalia, prout sunt distincta a singularibus, non nisi per opera-tionem animae (sicut Aristoteles et Commentator, ut puto, velle videntur) dicunt quodscibile pro re extra sic debet esse aeternum, quod semper sit aliqua res, vel semper sint

aliquae res, pro qua vel pro quibus semper termini conclusionis scibilis supponant, ad quodnon requiritur aliquam illarum rerum scibilium esse perpetuam, sed sufficit individuaeiusdem speciei perpetuo sibi succedere per generationem.

Buridan rejects this opinion on two grounds. In the first place, he believes that

it is proper to speak of knowledge of things even if no one of them exists, as in the

case of knowing about thunder on fair (lays. And secondly, he holds that knowl-

38 The reference is to Aristotle, Metaphysics, vII, 13, 1038b 1-33.

39 The position in question is likely the popular moderate realism or conceptualism, according to

which universals are real but are not separable from individuals. The object of knowledge is then the

nature as abstracted. Since Aristotle and Averroes maintain that the world is eternal, the series of in-

dividuals is endless, so that the nature as object of knowledge is also eternal. But Buridan's target is

likely one of the more recent Latin Averroists of Paris. Cf. Siger of Brabant, Quaestionessuperlibros Physicorum, ed. by P. Delhaye (Louvain, 1941), Book I, qu. 1: Et ideo dicendum quod de na-

turalibus est scientia. Possunt enim considerari in particulari et sic eorum non est scientia sed trans-

mutabilia sunt. Si autem considerentur quantum ad naturas eorum universales, sic manent et eorum

est scientia: quamvis enim natura humana corrumpiturin Socrate, tamen salvatur in alio. Ideo., etc.




edge is not just of currently existing things in any case, but of all things, present,

past, and future. His reason for saying this again reflects his nominalism. Since

the only real things are concrete particulars, knowledge can only be of particular

things. Not only are there no universals apart from things, but there is no naturein each individual that can be identified with the natures of other things. Thus, if

knowledge is only of presently existing things, a new demonstration would be

requiredfor each new thing. In order to know that tomorrow's triangle has three

angles, I will have to demonstrate this tomorrow.

Credoergo quod res scibiles,pro quibus termini conclusionis cibilis supponunt,non

oportetesse perpetuasaliquopraedictorummodorum,sed possibileest sic ex toto esse

corruptibiles,quod aliquandosit verum dicere quod nulla talis res est. Verbi gratia,crederemme veram haberescientiamde tonitruis et cometis, licet nulla modo essent

tonitrua et nullaestellae comatae.Neque mirum,quiasi mihi demonstratum uit quodomnis triangulushabet tres angulos, ego per huiusmodidemonstrationemnon solumhaberemscientiamde triangulis qui nunc sunt, sed et de praeteritiset futuris.Alitersequereturquodsi cras fieret novustriangulus,ego nescirem unc quodomnistriangulushabet tres, nisi mihi reiteraretur emonstratio unc continens lium novum triangulum,quodest absurdum icere.

Having rejected all these opinions, Buridan poses the problem Gregory raised.

If knowledge is not of essences, of universals, of causes, or of individual things

existing at given times, then how are we to account for the truth of these proposi-tions? All knowledge requires some sort of conformity of propositions to things,and propositions are true only if things are as the propositions state them to be.

But if propositions are about concrete, singular things that might not exist, then

it is possible for any such proposition to be false, so that none can be regarded as

necessary.

Sed tune occurritdubitatio,quoniam cientiarequiritconformitatemeu adaequationemad resscibiles,quiascientiaexigitquodsit veraeconclusionis, t veritasconsistit n adae-quatione ntellectusad resintellectas.Cum autem res intellectaenonessent,nullaerit adeasadaequatio,quodenimnihilest, nulliadaequatur.Ergode his quaenon sunt, scientiahaberinon potest.

(5) It is at this point that Buridan considers Ockham's view that all scientific

propositions must be either negative or hypothetical. The former possibility is not

really very interesting for present purposes. The only propositions to be made

negative are those dealing with things that cannot exist. Thus the proposition A

vacuum is nothing is understood as a negative proposition denying the existence

of a vacuum, and it may be included in science. This is based on the rule that a

negative categorical proposition asserts only that its terms do not stand for the

same things, so that if one of them stands for nothing at all, the proposition is

trivially true. And of course, if thethings designated

by thesubject

term cannot

possibly exist, then such a negative proposition is necessarily true.

Dicuntergoisti quodde his quaenonsunt, etiamquaenec essepossunt,possuntformari

propositiones erpetuaeveritatiscategoricae, ed tamennegativae,ut quodvacuumnihilest. Et ita scientiamhabeode vacuonegativam, bi enim salvaturadaequatiolla quaeadveritatempropositionis equiritur; on enimoportetquodsit aliquares quaesit aequalisintellectui.Sed hoc solumrequiritur: uod ta sit aut non sit in re sicutintellectus ntelligit




de re esse aut non esse. Intellectus igitur est verus quo intelligo vacuum non esse, quia itaest in re quod vacuum non est.

The second possibility is of greater interest, for this is the contention thatpro-positions of science, although categorical in form, are to be regarded as shorthand

hypotheticals. Thus the proposition Thunder is a sound in the clouds is true

even if there is no thunder at the time the proposition is written or uttered. For

this is merely a disguised rendering of the proposition If there is thunder, then it

is a sound in the clouds, which is true quite independently of current weather

conditionis.

Secundo, isti dicunt quod de his quae non sunt formari possunt propositiones perpetuaeveritatis affirmativae, sed tamen hypotheticae, ut 'Si vacuum est, vacuum est locus' vel'Si tonitrum est, ipsum est sonus in nubibus,' et ita de non entibus potest haberi scientia

affirmativa. In dictis enim propositionibus salvatur adaequatio intellectus ad res sufficiensad veritatem, quum intellectus non intelligit quod vacuum sit locus, sed quod esset locus siesset. Et ita licet in re vacuum non sit locus, tamen in re vacuum esset locus si esset.

Buridan is more in sympathy with this view. He does not state flatly that ista

opinio non placet mihi, as he has with the others, and he thinks that his only differ-

ence with these people arises from their ignorance of logic (ex defectu logicae).

They want to avoid substantial realism and to ground science in concrete par-

ticulars; but in supposing that every categorical proposition depends for its truth

upon the existence of things at some given time, they forget that tense belongs to

propositions, not to terms. When it is said that in a proposition of present tense,terms stand for presently existing things only, this is based on a way of usingterms in certain propositions, not on the nature of the term itself. Even thoughthe reference of a term in a proposition may be determined by the tense of the

proposition, in itself a term that signifies some things does not also signify anydeterminate time. Indeed it is just this that enables one to use the same term to

refer to things existing at different times. So long as propositions are regarded as

tensed, reference is restricted. But terms in themselves refer only to things, not to

times.40

Videtur enim mihi quod nomina quae significant res, nullum consignificandotempus deter-minatum, significant indifferenter res praesens, praeteritas et futuras. Nec mirum, quiapossum intelligere rem, nullum conintelligendo tempus determinatum. Unde possum apudintellectum componere inter conceptum rei et conceptum temporis, ita praeteriti velfuturi sicut praesentis, ut dicendo Caesar fuit, Caesar erit. Et ita non est inconveniens

aliquando terminum supponere pro praeteritis et futuris, sicut pro praesentibus.

Now in demonstrative science, propositions are necessary, i.e. true at all times.

These propositions, therefore, do not make an assertion about any particulartime, but about all times. Older logicians recognized this and allowed for it by

making a distinction between accidental and natural supposition. A term is saidto have accidental supposition if it stands for things existing at some determinate

40 Cf. Quine, Op. cit., p. 170: Ourordinary language shows a tiresome bias in its treatment of time.

... Moreover, the form that it takes - that of requiring that every verb form show a tense - is

peculiarly productive of needless complications, since it demands lip service to time even when timeis farthest from our thoughts.




time; and this is the sort of supposition possessed by terms in most propositions of

ordinary discourse. But a term taken in natural supposition is understood to

stand for all things that it signifies, regardlessof the time of their existence. And it

is this sort of supposition that is possessed by terms in propositions of demonstra-tive science. For these propositions are to be understood as referring directly to

individual concrete things, regardless of whether they presently exist.41So in

geometry we have knowledge of each individual triangle, whether or not every

triangle currently exists. And in biology we have knowledge of every man,whether or not any men at all presently exist.

Duplexenimsecundumantiquos ogicosest terminicommunis uppositio, cilicetnaturaliset accidentalis.Accidentalisest quandoterminussolumsupponitpro suppositisalicuiusdeterminati emporis.Naturalisautem quandosupponitindifferenter ro omnibussuis

suppositis, ive sintpraesentia, ivepraeteritavel futura.Et hocmodosuppositioneutun-tur scientiaedemonstrativae.Aliterper demonstrationem stendentemquodtriangulushabettres, etc., nonhaberemus cientiamde triangulis uturis,quodest inconveniens,utdictumfuit.

Of course, adds Buridan, to understand a categorical proposition of demonstra-

tive science is to understand the corresponding hypothetical. For if every trianglehas three angles, then if anything is a triangle, it has three angles. And if one

understands such a proposition hypothetically, then if he is shown any triangle,he will know that that triangle has three angles. But it is nonetheless true that so

long as such a proposition is understood hypothetically, knowledge of the proposi-tion cannot properly be said to be also knowledge of some particular triangles. For

a hypothetical proposition may be true even if its terms refer to nothing. On the

other hand, a categorical proposition in which the terms have natural suppositionaffords direct referenceto concrete particulars, and not only those of present time,but of all future times, so that knowledge of such a proposition is also properlysaid to be knowledge of particular concrete things.42

Sed statim diceretaliquis: Domine, vos coinciditiscum opinionepraecedente,quoniamdictaepropositionicibilivos assignatis ensuhypotheticum, t aliiconcedebantdetalibus

propositiones ypotheticasnecessarias t scibiles.'Respondeoquod forte haec opinioetilla eandem intendebantscientiam,sed differuntsecundum ogicamin modo loquendi.Primi enim non concedunt n praedictisrebuspropositionem ategoricam,n sensu cate-

gorico.Egoautemconcedoeamesseveramsecundum uppositionem aturalem.

VI

The natural supposition used by Buridan derives from the Summulae Logicalesof Peter of Spain, where it is mentioned only briefly. According to Peter, supposi-

41Ibid.: We may conveniently hold to the grammatical present as a form, but treat it as temporallyneutral. One does this in mathematics and other highly theoretical branches of science without de-

liberate convention. But medieval logicians do nothing without deliberate convention, so that the

discovery of a new canon or the reinterpretation of an old one may be a matter of some moment.

42 Of course, propositions of demonstrative science do not depend on reference for their truth. Theyare necessary as conclusions of demonstrations, and even if they are principles rather than conclu-

sions, their truth is established by an analysis of meanings, although such analysis is undertaken on

the basis of abstractions derived from sense experience of concrete things. Cf. D. Webering, TheoryofDemonstrationAccordingto William of Ockham(St Bonaventure, 1953).




tio naturalis is the taking of a common term for everything of which it is of a

nature to be predicated, as 'man' taken according to its nature, has suppositionfor all men who are and who were and who will be. 43This is his only remark

about the matter, and it is not clear just how he intended it to be taken.44Further-more, it does not occur in many later logicians, such as Ockham, Walter Burleigh,Albert of Saxony, and Marsilius of Inghen, and Boehner remarks simply that it

was (Iroppedby other logicians. 45Yet suppositio naturalis quite clearly does occur in Buridan. And Buridan's use

of it to establish direct reference to particular things is certainly in line with the

Ockhamnistendency toward both logical nominalism and metaphysical realism.46

It is, therefore, curious that this sort of suppositio is so conspicuously absent from

the Ockhamist tradition. Ockhanl was surely familiar with the logic of Peter of

Spain, and others such as Albert of Saxony and Marsilius of Inghen must haveknown Buridan's use of suppositio naturalis. And yet none of them mentions it

even to reject its use.

I do not propose to solve this puzzle in the present paper, but I would like to

offer the suggestion that the answer may be found in further study of the logic of

the realist tradition. Of the fourteenth-century realists, only Walter Burleigh has

been studied in any detail, and suppositio naturalis does not occur in his logical

writings. But there is some evidence that it was current in the fourteenth century.for in his De suppositionibus, written in 1372, Vincent Ferrer discusses it in what

seems to be routine fashion.47In fact Vincent's use of it provides an interestingrealistic counterpart to Buridan's discussion.

Vincent writes that a subject term always has suppositio naturalis when the

proposition in which it occurs is an essential predication, i.e. when the predicateterm designates the essence of the things designated by the subject, as in the

proposition Man is an animal. 48In such a proposition, says Vincent, the thing

43 Petri Hispani Summulae Logicales, ed. by I. M. Bochenski (Torino, 1947), 6.04: Suppositio na-

turalis est acceptio termini communis pro omnibus de quibus aptus natus est praedicari, ut 'homo' per

se sumptus de natura sua habet suppositionem pro omnibus holminibusqui sunt et qui fuerunt et quierunt.

44Compare the interpretation of J. P. Mullally, The Summulae Logicales of Peter of Spain (Notre

Dame, Indiana, 1945), p. xlviii, with that of P. Boehner, MedievalLogic (Manchester, 1952), pp. 33-34.

Buridan's interpretation differs from both of these, but of the three, Boehner's is still most convincing.45Boehner, Op. cit., p. 33. Albert of Saxony, Logica (Venice, 1522), III, Ch. 10, speaks of materia

naturalis as that possessed by a proposition whose truth-value is determinable by virtue of the mean-

ings of its terms (i. e. is either analytic or contradictory), and of course, all affirmative propositions of

demonstrative science are of this kind. How close this comes to Buridan's suppositio naturalis could

not be said without a full investigation of the nominalists' view of the relation of meaning to extension.

It may well be that these philosophers make no distinction between identity of meaning and omni-

temporal identity of reference, but the present state of research does not permit a judgment on thematter.

46 Buridan also mentions this use of natural supposition in the Perutile compendiumtotius logicae,Tract iv, but it is not included in his discussions of supposition in the Sophismata.

47 De suppositionibus dialecticis, in Vol. 1 of Oeuvresde Saint Vincent Ferrier, ed. by Le Pere Fages

(Paris, 1909), Chs. 3-4.48 Ibid., Ch. 3: suppositio naturalis dicatur, quando terminus communis accipitur respectu praedi-

670




understood by the subject term is understood absolutely, by its essence or na-

ture, i.e. in abstraction from its existence.49This means that such a proposition is

true for all times and for all designata, precisely because it abstracts from all

conditions of existence.50Propositions of demonstrative science are thus neces-sary, not because they are omnitemporal, but because they are atemporal.

Of course, no nominalist could agree to this use of natural supposition, since it

depends on a positing of universal essences as distinct from existence. And Vin-

cent's use of this type of suppositio may be unique even in the realist tradition.

But it is interesting to speculate that it was commonly used by realists and that

its absence from most nominalist texts was due to a conviction that natural sup-

position was too heavily tainted by the metaphysic of essences.

On the other hand, Buridan's use of it proves that it was not altogether foreign

to the Ockhamist tradition, as Ivo Thomas has claimed.51And the adaptabilityof such a logical device to radically opposed metaphysical commitments supportsthe claim that the terminist logic was in itself largely ontologically neutral and so

could be used to provide an analytical tool for all thinkers.

VII

Buridan's use of natural supposition for propositions of demonstrative science

is part and parcel of an attempt to ground knowledge in the world of concrete

particulars, by means of a strictly nominalistic language in which every term in

propositions of science is referential. This emphasis has consequences for the

theory of language, and Buridan realizes that he must take account of these.

Thus, in the Sophismata, he considers a number of problems related to the ques-tion of reference in scientific propositions. Here I can mention only one represen-tative example.52Suppose, he says, that Socrates is an astronomer and so knows a

great deal about the stars. Further suppose that Socrates is locked in a dungeon,so that he does not know whether it is day or night. Now in spite of this, Socrates

can be said to know that some stars are above his hemisphere, since he knows that

some stars or other are above his hemisphere at any time. Finally, suppose that

the stars of the Gemini are indeed the only stars above at the moment. If Socratesis asked whether the stars of the Gemini are above, he will reply that he does not

know. And yet if knowledge is of particulars, then if Socrates knows anything, he

cati sibi essentialiter convenientis, quemadmodum est in ista propositione 'Homo est animal.' Tunc

enim res per terminum huiusmodi importata sumitur absolute per suam essentiam seu naturam, ut

ibidem clarius habetur.49Ibid., Ch. 4: Tunc autem dico praedicatum essentialiter convenire subiecto quando praedicatum

pertinet ad essentiam subiecti, ut 'Homo est rationalis.'

50Ibid.: omnis propositio cuius subiectum habet suppositionem naturalem seu demonstrativam estuniversaliter vera, scilicet pro omni tempore et pro omnibus suppositis.

51I. Thomas, Vincent Ferrer's De Suppositionibus, Dominican Studies, v (1952), 90.

52Sophismata,Ch. 4, fourteenth sophisma (Sortes astrologus scit aliqua astra esse supra emisperium

nostrum). This and related sophisms have been discussed by E. A. Moody in an as yet unpublished

paper. However, Professor Moody does not relate these sophisms to Buridan's general position on

propositions of demonstrative science, which is my only aim here.

671




must have knowledge of the Gemini. Considered as a problem of modal logic, the

question is whether from the proposition Socrates knows that some stars are

above, one can infer the proposition Some stars are such that Socrates knows

them to be above. 53For if we allow this inference, we must also allow that from

the latter proposition, one can infer the proposition Socrates knows the Gemini

to be above.

Buridan recognizes full well that he must accept these inferences, since Socra-

tes' knowing at all depends on his knowing some particular things. But he tries to

show that he can allow these inferences without offending either logic or his view

of science. He maintains that all knowledge is indeed of concrete particulars, but

knowledge is always by means of a specific mental act of knowing or propositionalattitude. Buridan attempts to meet both these conditions by saying that terms

following the verb to know not only designate the usual objects but also name

(appellant) the acts of knowing (rationes)that constitute the mode of referringto

those objects.54Thus the proposition Socrates knows that some stars are above

is properly paraphrased as By Socrates, some stars are known to be above by

[some stars are above], where the bracketed expression designates not a proposi-tion, but a propositional attitude, the act of knowing stars in which Socrates

engages.55And from this can follow the proposition By Socrates, the Gemini are

63 Ibid.: videtur mihi esse dicendum quod tota eius difficultas consistit in hoc, utrum sequitur: scio

aliquid astrum esse supra emisperium nostrum, ergo aliquid astrum scio esse supra emisperium nos-trum. Framed in this way, the problem is whether one is to claim that terms occurring in modal con-

texts (i. e. following modal verbs, such as know, believe, etc.) have referenceto concrete things or

are referentially opaque, or perhaps take some intensional entities as referents. Or if names are re-

placed by bound variables, the question is whether one can allow quantifying words outside such con-

texts to bind variables within them. This is a problem much discussed in recent years by Frege, Car-

nap, Church, Quine, and others (the phrase referential opacity is from Quine, Op. cit., p. 141). In

these terms, Buridan's problem is to retain referential transparency in (allow quantification into) at

least those contexts following the verb to know (scire), without being forced to say that the refer-

ents of such terms (values of such variables) are intensional entities.

64 Ibid., twelfth sophisma: Sciendum est quod ista verba 'intelligo,' 'cognosco,' 'scio,' et huiusmodi

. . faciunt in terminis cum quibus construuntur quosdem modos speciales appellationum. Nam quiaeandem rem possum cognoscere secundum multas diversas rationes et isti rei secundum diversas ra-

tiones diversas nomina imponere ad significandum eam. Ideo talia verba faciunt terminos cum quibusconstruuntur appellare rationes secundum quas imposita sunt nomina ad significandum et non solum

res cognitas ad extra sicut faciunt alia verba. The entire fourth chapter of the Sophismata is devoted

to the property of appellatio. This is an important discussion, since it treats of relative description,

multiple quantification and personal identity. But it cannot be treated here, for it is an extremely

complex doctrine. Indeed, like the theory of suppositio, it appears to constitute a doctrinal cluster,rather than a single doctrine.

55This way of paraphrasingthe proposition is not Buridan's, since he does not actually provide any

paraphraseat all. But this way of doing it seems to me to agree most nearly with the spirit of his re-

marks. The advantage of this paraphrase is that it makes explicit the referential transparency of

these contexts. The chief disadvantage is that it makes the transparency explicit by removing the

term from the modal context and so perhaps giving the false impression that the issue has been dodgedrather than met. However, the two other most likely paraphrases seem even less desirable. One mightretain something very like the original form by a paraphrasesuch as Socrates [knowsthat some stars

are above], where again the bracketed expression designates the act of knowing. This removes the




known to be above, by [some stars are above]. Now if Socrates is asked whetherthe Gemini are above, he will, of course, reply that he does not know. But what is

actually being asked in this case is whether he has such knowledge of the Gemini

by means of the propositional attitude [the Gemini are above], which he maywell deny, even though he does indeed know the Gemini to be above by means ofanother mental act.

This way of handling the reference of terms following the verb to know is

clearly in line with the position stated in the Question on the Ethics discussed

above, and it reinforces Buridan's insistence on knowledge as having always con-crete objects. And at the same time, it is an interesting contribution to the ques-tion of referencein modal contexts. Whether Buridan's way of handling this prob-lem is an altogether happy one, and if so whether it can be extended to other

modal verbs, are questions that cannot be discussed here.56But enough has beensaid to illustrate the importance attached to logical analysis by the Ockhamisttradition. Metaphysical positions did not usually derive from linguistic analysis,but once ontological commitment to concrete singulars was made, these philoso-phers saw quite well the need to make sense of the commitment by developing a

strictly nominalistic language. This means that quite apart from the inherent

interest mediaeval logic may have, it also is a major key to understanding later

mediaeval thought. Buridan's discussion of scientific propositions is only a single

example.

YALE UNIVERSITY

temptation to think of knows as a transitive verb which must take a complexesignificabileas objectBut this will not do, since it makes everything following Socrates one composite general term used

attributively, which does not provide the desired reference to the Gemini and which forbids the de-

sired inferences, since one cannot quantify into a term. An alternative paraphrase might be Socrates

knows that some stars are above by [somestars are above]. But while this has certain advantages, it

does appear to make the object of the act of knowing not stars but something expressed by that some

stars are above, which again looks much like the complexe significabile that Buridan so wants to

avoid.56Buridan does extend his solution to other cognitive verbs, such as intelligo, opinor, and credo,to

verbs of desire, such as volo and appeto, and to the three verbs of obligation, debeo,promitto and

obligo.The extension seems most plausible in the case of a cognitive verb, such as credo,where a men-

tal act is clearly involved. But even here there is the difficulty that Buridan's view requires that the

terms in such contexts have referents (although the referents might not currently exist), whereas

some mental acts appear to have no objects at all. Thus, if I believe that a chimera is a mammal, the

object of my belief not only does not currently exist, but could not possibly exist. And in the case of

other verbs, such as debeo,Buridan's position is less plausible, for it is not only the case that a proposi-tion such as I oweyou ahorse might be true although there were no horses, but to owe does not seem

to be to perform a mental act at all. Here it does seem better to treat owe you a horse as a compos-

ite general term used attributively and to say that the debt has been satisfied when that attributiveuse is no longer proper. It may be possible to interpret Buridan's view so as to account for these and

other difficulties, and an attempt to do so would prove of interest; but the view cannot stand in its

unqualified form.

scott buridanobjectdemonstrativescience 1965

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