Arabic philosophy

the predicate term “a”; that is, the full predicate of the second and

third propositions in (1) is “necessarily a.” This is what is referred to

among medieval Latin writers as a de re reading of the modal proposition.

At the same time, Aristotle wants the proposition

(3) Every a is necessarily b.

to convert as

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Logic 257

(4) Some b is necessarily a.

which suggests that he reads “necessarily” in this case as belonging

to the whole proposition rather than merely to the predicate term;

he is taking the proposition (3), in short, as “necessarily, every a is

b.” Taking the proposition to assert that “every a is b” is necessary

is to take it in what is known among medieval Latin writers as a de

dicto reading. The problem is that if the de dicto reading is adopted,

then syllogism (1) is no longer valid; if the de re reading is adopted,

the conversion of (3) no longer goes through as (4). Aristotle never

refers to the distinction between de re and de dicto readings, and

seems to propose a uniform reading for his modals throughout the

exposition.26 Is he right to do so?

The Farabian tradition

At this point, I will take a considerable detour through the earliest

Arabic treatment of the modal logic, so I can examine the way

the Farabian tradition tried over two and a half centuries to refine

a solution to the problem. When al-F ¯ar¯ab¯ı began his work in the

early tenth century, he had the relevant chapters of the Prior Analytics

(chs. 8–22 of book I, translated by an otherwise unknown collaborator

working with H.

unayn ibn Ish. ¯aq, probably finished some

time between 850 and 875), and a mass of commentatorial material

translated three or four decades later, probably including Alexander,

Ammonius, Themistius, and others.We have lost the work inwhich

al-F ¯ar¯ab¯ı set out his exegesis, but his approach to one particular problem

was explicitly adopted and extended by Averroes (d. 1198).27 By

and large, the Farabians wanted to give a way to make sense of the

difficult passages inAristotle’s modal syllogistic, and proffered ways

of construing the text to do that. Their interests were exclusively textual,

in the sense that it is hard to picture a freestanding system that

would make the distinctions their exegetical posture led them to

make. They did not make use of the distinction between de re and

de dicto readings. But they accepted the validity of syllogism (1), the

invalidity of syllogism (2), and tended to focus their concerns on the

proper converse of (3). One concrete counterexample to the inference

of (4) from (3) that Farabian logicians dealt with was:

(5) Every literate being is necessarily a human being,

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which, given the way things are, seems to be true, but which would

convert to the untrue

(6) Some human being is necessarily literate.

Developing a distinction found in Aristotle between terms taken to

be per se (bi-al-dh¯ at) and per accidens (bi-al-‘arad.

) – too complex

for the present chapter – the Farabians would hold “literate being”

to be merely per accidens, expressing a peculiarity had only by the

predicate, human being, but not had necessarily by any. So (5) is only

true as a per accidens necessary proposition because one of the terms

is only per accidens. “Human being,” by contrast, is said of things

essentially, that is, per se. Aristotle only intends to be able to infer

(4) from (3) if (3) is a per se necessary proposition, with per se terms

like

(7) Every human being is necessarily an animal.

A simplified version of this approach was adopted by medieval Latin

logicians, notably Robert Kilwardby (d. 1279), though we are unable

to say what source he may have followed. Here is his statement of

the argument:

When it is said: “Every literate being is necessarily a human being,” this

subject is not something which can be said per se of this predicate, but since

“literate being” is not separated from that which belongs to a human being

itself, the proposition is conceded to be necessary, but when a proposition is

necessary in this way it is necessary per accidens. Therefore, when Aristotle

says that necessary propositions are convertible, he means only that the

propositions which are necessary per se are convertible.28

In another essay, Averroes gave a statement of a series of problematic

passages in Aristotle, followed by a declaration of why he

wanted to find a solution to them:

These are all the doubts in this matter. They kept occurring to us even when

we used to go along in this matter with our colleagues, in interpretations by

virtue of which no solution to these doubts is clear. This has led me now

(given my high opinion of Aristotle, and my belief that his theorization is

better than that of all other people) to scrutinize this question seriously and

with great effort.29

Nothing could better characterize the way the Farabian approaches

the Aristotelian text; and it is this approach which Avicenna rejects.

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The Avicennian tradition

Which is not to say Avicenna had little respect for Aristotle, or that

his syllogistic is presented without reference to the system of the

Prior Analytics. But Avicenna was sure he knew the system which

Aristotle was trying to put forward, and used that system as a way to

judge when to depart from the literal sense of the text. On a related

point, he said:

You should realize that most of what Aristotle’s writings have to say about

the modal mixes are tests, and are not genuine opinions – this will become

clear to you in a number of places.30

The Avicennian approach to the problem of interpreting Aristotle

was to accept (1), reject (2), and then simply reject the claim that (3)

converts as (4). The counterexample Avicenna used was every laughing

being is necessarily a human. It is obvious that it will convert

to some humans are laughing,

but it does not necessarily convert as a necessary, for it may be that the

converse of the necessary is possible; it may be that J (such as laughing)

necessarily has B (such asman), but that B (such asman) does not necessarily

have J (such as laughing). Whoever says otherwise, and has sought to find a

stratagem for it, do not believe him.31

One of the stratagems expressly ruled out by Avicenna is the

Farabian.32 In other words, Avicenna did not seek to exclude certain

propositions from the Aristotelian rule, he just changed the rule. The

Farabians changed their system to fit the text, Avicenna changed the

text to fit his system.

That said, Avicenna did develop his own stratagems to save

Aristotle’s text. One of these stratagems is the was. fı¯/dha¯ tı¯ distinction

whose origin we seek, which he introduced when discussing

propositions in a necessary mode, but which he first used

in discussing propositions with no explicit modality (what he called

“absolute” propositions).33 Here is the introduction of the different

readings:

Necessity may be (1) absolute, as in God exists; or it may be connected

to a condition. The condition may be (2) perpetual for the existence of the

substance (dha¯ t), as in man is necessarily a rational body. By this we do not

mean to say that man has been and always will be a rational body, because

that would be false for each given man. Rather, we mean to assert that while

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he exists as a substance, as a human, he is a rational body. Or the condition

may be (3) perpetual for the subject’s being described (maws.

u¯ fan) in the way

it is, as in all mobile things are changing; this is not to be taken to assert

that this is the case absolutely, nor for the time [the subject] exists as a

substance, but rather while the substance of the moving thing is moving.

Distinguish between this condition and the first condition, because the first

has set down as the condition the principle of the substance, “man,” whereas

here the substance is set down with a description (s.

ifa) that attaches to the

substance, “moving thing.” “Moving thing” involves a substance (dha¯ t wa

jawhar) to which movement and non-movement attach; but “man” and

“black” are not like that.34

How did Avicenna use this distinction? A dha¯ tı¯ reading is like the

de re reading mentioned above, whereas the was. f¯ı reading takes a

proposition like every a is necessarily b as properly every a is necessarily

b while a. The distinction is probably best explained by example.

All who are sitting may be standing is true as a dha¯ tı¯ reading;

each person who sits can at a later time stand, all other things being

equal. Under this reading, all men are necessarily rational, all young

men may be old men, all bachelors may be married men, and all

who are sleeping are waking. In the was. f¯ı reading, all men are necessarily

rational is still true, but all who are sitting may be standing

taken as a was. f¯ı (which is to say, all who are sittingmay be standing

while sitting) is false. False too are the propositions claiming that

all bachelors may be married men, and that all who are sleeping are

waking.

The right way to understand Aristotle’s syllogistic was as a system

involving propositions in the dha¯ tı¯ reading and, so understood, the

converse of (3) is not (4). Was there a way to have Aristotle’s claim

make sense? By taking (3) in the was. f¯ı reading. In fact, according

to Avicenna, the move from (3) to (4) was not the only place where

Aristotle needed to be read charitably, nor was it the only place the

was. f¯ı reading could help. He also thought it could preserve the Aristotelian

stipulations for the contradictories and converses of absolute

propositions. Nas.ı¯r al-Dı¯n al-T. u¯ sı¯ (d. 1272), one of Avicenna’s great

thirteenth-century commentators, tells us why Avicenna developed

the distinction:

What spurred him to this was that in the assertoric syllogistic Aristotle and

others sometimes used contradictions of absolute propositions assuming

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them to be absolute; and that was why so many decided that absolutes did

contradict absolutes. WhenAvicenna had shown this to be wrong, he wanted

to give a way of construing [those examples from Aristotle].35

the nature of later arabic logic

It is from Avicenna’s exercise in exegetical charity that al-K¯atib¯ı and

his predecessors found the distinction they deployed so extensively.

It is instructive to examine how al-K¯atib¯ı used the distinction, and

some of the results to which he came, because that in turn illustrates

certain characteristic aspects of later Arabic logic.

Firstly, al-Ka¯ tibı¯ never brought the dha¯ tı¯/was. fı¯ distinction to bear

on any problem inAristotle’s Prior Analytics, nor, for that matter, on

any problem in Avicenna’s logic. Al-K¯atib¯ı was setting down a system

of modal logic, not writing a commentary on someone else’s system.

But the system he put forward was based closely on Avicenna’s.

In other words, the system to which immediate reference was made

by the later logicians writing in Arabic – al-K¯atib¯ı is representative

in this respect – was Avicenna’s, not Aristotle’s.

Secondly, on looking at the specific deductions in al-K¯atib¯ı’s treatment,

one finds the following: if the premises are in the dha¯ tı¯ reading,

then syllogism (1) is valid, and syllogism (2) invalid. The converse of

(3) in the dha¯ tı¯ reading is not (4), but nor is it the one-sided possible

that Avicenna took it to be. Al-K¯atib¯ı took its converse instead to be

a proposition in the was. f¯ı reading, some b is at least once a while

b – I will not go into his proof for the conversion here. So although

the system was based closely on Avicenna’s, it was not Avicenna’s.

It was rather a modification of that system, and the modifications

were in some cases extensive. Among other things, they made the

system completely useless for one of the tasks Avicenna had inmind

when he produced it, which was to use it tomake sense of Aristotle’s

Prior Analytics.

We may say that later Arabic logic is Avicennian, then, but that

claim should be understood fairly specifically. Firstly, it is Avicennian

in that the base system taken as the object of debate and

repair is Avicennian. And secondly, it is Avicennian in its attitude

to past authority – just as Avicenna had rejected Aristotle’s

doubtful claims, so too the later logicians writing in Arabic felt free

to reject Avicenna’s doubtful claims.36 Further, they did not share

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his interest in the work of the First Teacher. But by developing,

extending, and repairing the various logical insights of Avicenna

as exposited through his conversation with Aristotle’s Organon,

these later logicians offered up vast quantities of material on important

logical problems. It is the task of present and future generations

of scholars to begin to take stock of the quality of this

material.37

notes

Thanks are due to Henrik Lagerlund, John Marenbon, Rob Wisnovsky,

and the editors of this volume for reading this chapter and offering

various helpful suggestions.

1 For information on these interesting topics, see respectively J. van Ess,

“The Logical Structure of Islamic Theology,” in von Grunebaum [184],

21–50; and B. Weiss, “Ilm al-Wad.

‘: An Introductory Account of a Later

Muslim Philological Science,” Arabica 34 (1987), 339–56.

2 The whole of the Shamsiyya is available in translation, though a new

translation is overdue. See A. Sprenger (ed. and trans.), Bibliotheca

Indica: A Collection of Oriental Works, no. 88: First Appendix to the

Dictionary of Technical Terms used in the Sciences of the Mussulmans,

containing the Logic of the Arabians (Calcutta: 1854); this partial translation

is completed in Rescher [178], 39–45. Rescher added to his translation

a somewhat faulty analysis of the logic; he corrected it later in

his study with A. vander Nat [180].

3 In Sh¯ı‘ite seminaries, the commentary by al-‘All¯ama al-H. ill¯ı (d. 1325)

on the Tajr¯ıd al-mant. iq of Nas.ı¯r al-Dı¯n al-T. u¯ sı¯ (d. 1274), the Jawhar

al-nad.

ı¯d fı¯ sharh. Kita¯b al-tajrı¯d, served in the role of introductory logic

text.

4 I. M. Bochenski, A History of Formal Logic, trans. I. Thomas (Notre

Dame, IN: 1961); see esp. “On the History of the History of Logic,”

4–10.

5 See, e.g., K. Jacobi, “Logic: The Later Twelfth Century,” in P. Dronke

(ed.), A History of Twelfth-Century Western Philosophy (Cambridge:

1988), 227–51, at 236ff. Cf. S. Pines, “A Parallel in the East to the Logica

Vetus,” in Pines [37], 262–6, and Gutas [57].

6 Bochenski, History, 6–9.

7 As an example, see the introduction of the otherwise extremely valuable

Jabre et al. [174], v–ix.

8 Bochenski, History, 152.

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Logic 263

9 Made for example by Madkour [176], at 268–9.

10 See, e.g., Gutas [56], 246.

11 See Gutas [57].

12 Gutas [58], 61.

13 Peters [61], 7–30; cf. Lameer [175], ch. 1. See also H. Hugonnard-Roche,

“Remarques sur la tradition arabe de l’Organon d’apr`es le manuscrit

Paris, Biblioth`eque nationale, ar. 2346,” in Burnett [50], 19–28; and

the review of the chapter by J. Lameer, “The Organon of Aristotle

in the Medieval Oriental and Occidental Traditions,” Journal of the

American Oriental Society 116 (1996), 90–8.

14 Gutas [93], 197–8; see the revised treatment ofh.

ads by Gutas in “Intuition

and Thinking: The Evolving Structure of Avicenna’s Epistemology,”

in Wisnovsky [104], 1–38.

15 Ibn Khaldu¯ n, Prole´gome`nes d’Ebn-Khaldoun: texte arabe, part 3, ed.

M. Quatrem`ere (Paris: 1858), 112–13; cf. the translation by F. Rosenthal

in his The Muqaddimah of Ibn Khaldun (London: 1958), vol. III, 142–3.

16 D. S.Margoliouth, “TheDiscussion between Abu¯ BishrMatta¯ and Abu¯

Sa‘¯ıd al-S¯ır ¯ af¯ı on the Merits of Logic and Grammar,” in Journal of the

Royal Asiatic Society (1905), 79–129 at 115–16; cf. Endress [172], 163–

299.

17 Al-F¯ar ¯ab¯ı, Kit ¯ ab al-qiy ¯ as al-s.

aghı¯r, in al-Mant. iq ‘inda al-Fa¯ ra¯bı¯, ed. R.

al-‘Ajam, vol. II, 68; cf. A. I. Sabra, review of N. Rescher’s Al-Fa¯ ra¯bı¯’s

Short Commentary on Aristotle’s Prior Analytics, in Journal of the

American Oriental Society, 85 (1965), 241–3, at 242a.

18 Lameer [175], chs. 6, 7, and 8.

19 Al-Mustas. f ¯ a min ‘ilm al-us.

u¯ l (Cairo: 1938). I tend to think the legal

use of logic was the most important factor in its acceptance, although

other factors are cited (e.g., by Ibn Khaldu¯ n) like the theological use of

logic.

20 I. Goldziher, “The Attitude of Orthodox Islam toward the ‘Ancient

Sciences’,” in M. Swartz (ed. and trans.), Studies on Islam (Oxford:

1981), 185–215, at 205–6.

21 W. B. Hallaq, Ibn Taymiyyaagainst the Greek Logicians (Oxford: 1993),

141.

22 Cf. Bochenski, History, 159–62. It is worth noting that – to the best

of my knowledge – there was no treatment in the Arabic manuals

paralleling the treatment in the later Latin manuals of obligations and

insolubles, among other things, but one could find parallel treatments

of these topics outside the logic manuals.

23 Avicenna, al-Isha¯ ra¯ t wa al-tanbı¯ha¯ t, ed. S. Dunya, 2nd edn. (Cairo:

1971), 374; cf. S. Inati, Ibn Sina: Remarks and Admonitions,

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264 tony street

part 1: logic (Toronto: 1981), a somewhat problematic translation

which records the Arabic pagination in the margin.

24 Discourse on theCategorical and Hypothetical Syllogistic,with a Criticismof

the Conjunctive Syllogistic of Avicenna, in Rasa¯ ’il falsafiyya:

Maqa¯ la¯ t fı¯ al-mant. iq wa al-‘ilm al-t.abı¯‘ı¯ li-Abı¯ al-Walı¯d Ibn Rushd,

ed. J. ‘Alaw¯ı (Casablanca: 1983), 187–207.

25 Black [170], 97ff.

26 A succinct statement of the problem is given in H. Lagerlund, Modal

Syllogistics in the Middle Ages (Leiden: 2000); see ch. 1 generally, and

esp. 12–14.

27 A Criticism of Avicenna’s Doctrine of the Conversion of Premises,

in ‘Alawı¯, Maqa¯ la¯ t, 100–5, at 104–5; Averroes defends al-Fa¯ ra¯bı¯’s

approach which had been attacked by Avicenna, though al-F ¯ar¯ab¯ı came

to the problem from the other direction, by considering the converse

of the contingent proposition, every human being may or may not be

literate. In fact, matters are much more complicated than I indicate

in the text, because Averroes kept shifting his position on the modal

syllogistic (see Elamrani-Jamal [171]; it is the last attempt by Averroes

that I refer to here). For details of this extremely technical system, see

now Thom [183], ch. 5.

28 Quoted in Lagerlund, Modal Syllogistics, 28; I have very slightly modified

the translation.

29 ‘Alawı¯, Maqa¯ la¯ t, 181.

30 Avicenna, al-Shifa¯ ’, al-qiya¯ s, ed. S. Zayed (Cairo: 1964), 204. For the

full system developed by Avicenna, see now Thom [183], ch. 4.

31 Avicenna, al-Isha¯ ra¯ t, 334–5.

32 Avicenna, al-Shifa¯ ’, al-qiya¯ s, 209–10; this is the attack against which

Averroes defended al-F ¯ar¯ab¯ı.

33 See Lameer [175], 55ff. for the reasons the term“absolute” was adopted.

34 Avicenna, al-Ish¯ ar ¯ at, 264–6. Maws.

¯ uf and s.

ifa come from the same

Arabic radicals as was. f¯ı, the “descriptional.”

35 Al-T. u¯ sı¯, Sharh. al-Isha¯ ra¯ t, printed with Avicenna, al-Isha¯ ra¯ t, 312.

36 An attempt at characterizing the attitude and practice of post-

Avicennian philosophers is made in Gutas [94].

37 Some suggestions for further reading: aside from the books referred to

in the footnotes, the following are particularly useful. For an introductory

overview that stretches to cover aspects of non-Aristotelian logic,

and which is very helpful for historical context, see the entry Mantik.

by R. Arnaldez in Encyclopaedia of Islam [16]. For a rapid historical

sketch, overview of the genres of logical writing, and extensive bibliography,

see Gutas [173]. For a longer historical survey, concentrating on

the period 900–1300, see Street [182]. For a treatment of whether logic