Barnes Jonathan. Truth, etc

Подождите немного. Документ загружается.

450 When is a Syllogism not a Syllogism?

things, indeed, it deems necessary and preliminary to itself; but it passes judgement

on them (as it does on everything else), and deems some of them useful and others

superﬂuous and appropriate only to a method which is interested in such things.

(enn i iii 4 [18–23])⁷

Dialectic—Plotinian dialectic—is not to be identiﬁed with logic or with

syllogistic any more than it is to be identiﬁed with grammar.

The fundamental difference between dialectic and syllogistic emerges a

little later in Plotinus’ argument. I quote an extended chunk:

Well then, is philosophy the most honourable thing? Or is dialectic the same as

philosophy? Or is it a part—the honourable part—of philosophy? For certainly it

mustn’t be thought to be one of the philosopher’s tools: it is not just empty theorems

and rules—rather, it is about objects and it has the things which exist as, so to

speak, its matter. It sets after them methodically, grasping the objects as well as the

theorems. As for falsity and sophism, it recognizes them incidentally when someone

else commits them, judging falsity to be alien to its own truths and recognizing, when

it is brought forward, whatever is contrary to the rule of truth. So although it doesn’t

know about propositions (which, after all, are merely letters), nonetheless, insofar as

it knows the truth it knows what they call propositions, and in general it knows the

movements of the soul—what the soul posits and what it rejects, whether it rejects

what it posits or something else, whether things are different or the same—and it

attends to such items when they are presented to it, as perception does, but it leaves

careful study of such things to another art which delights in them.

(enn i iii 5 [8–23])⁸

Dialectic is not an empty or bare subject: it deals with objects, and the

things which exist are its subject-matter. Logic, on the other hand, is empty

theorems and empty rules. Its propositions are just letters. That is why logic

⁷ … τὴν λεγομένην λογικὴν πραγματείαν περὶ προτάσεων καὶ συλλογισμῶν, ὥσπερ ἂν τὸ

εἰδέναι γράφειν, ἄλλῃ τέχνῃ δοῦσα· ὧν τινα ἀναγκαῖα καὶ πρὸ τέχνης ἡγουμένη, κρίνουσα

δὲ αὐτὰ ὥσπερ καὶ τὰ ἄλλα καὶ τὰ μὲν χρήσιμα αὐτῶν, τὰ δὲ περιττὰ ἡγουμένη καὶ μεθόδου

τῆς ταῦτα βουλομένης.

⁸ τί οὖν; ἡ φιλοσοφία τὸ τιμιώτατον; ἢ ταὐτὸν φιλοσοφία καὶ διαλεκτική; ἢ φιλοσοφίας

μέρος τὸ τίμιον; οὐ γὰρ δὴ οἰητέον ὄργανον τοῦτο εἶναι τοῦ φιλοσόφου· οὐ γὰρ ψιλὰ

θεωρήματά ἐστι καὶ κανόνες, ἀλλὰ περὶ πράγματά ἐστι καὶ οἷον ὕλην ἔχει τὰ ὄντα· ὁδῷ

μέντοι ἐπ᾿ αὐτὰ χωρεῖ ἅμα τοῖς θεωρήμασι τὰ πράγματα ἔχουσα· τὸ δὲ ψεῦδος καὶ τὸ

σόφισμα κατὰ συμβεβηκὸς γινώσκει ἄλλου ποιήσαντος ὡς ἀλλότριον κρίνουσα τοῖς ἐν αὐτῇ

ἀληθέσι τὸ ψεῦδος, γινώσκουσα ὅταν τις προσαγάγῃ ὅ τι παρὰ τὸν κανόνα τοῦ ἀληθοῦς.

περὶ προτάσεων οὖν οὐκ οἶδε—καὶ γὰρ γράμματα—εἰδυῖα δὲ τὸ ἀληθές οἶδεν ὃ καλοῦσι

πρότασιν, καὶ καθόλου οἶδε τὰ κινήματα τῆς ψυχῆς, ὅ τε τίθησι καὶ ὃ αἴρει, καὶ εἰ τοῦτο αἴρει

ὃ τίθησιν ἢ ἄλλο, καὶ εἰ ἕτερα ἢ ταὐτά, προσφερομένων ὥσπερ καὶ ἡ αἴσθησις ἐπιβάλλουσα,

ἀκριβολογεῖσθαι δὲ ἑτέρᾳ δίδωσι τοῦτο ἀγαπώσῃ.

Plotinus on Logic 451

is at best a tool for the philosopher to use, while dialectic is not a tool of his

trade but a part of his expertise.

The propositions of logic are bare: they are mere letters. Plotinus is usually

taken to mean that logic deals with linguistic items, with sentences, rather

than with the things or facts which sentences express. But I wonder if the

logician’s letters are not literally letters. When Aristotle assures us that if A

holds of every B and B of every C, then A holds of every C, then that is

a bare rule, there is no matter to it, it is mere letters. The logician deals

with schemata, with matterless forms; and so he does not deal in substantive

truths.

To be sure, a dialectician recognizes such items when they present them-

selves to him. That is to say, a dialectician will recognize that this concrete

argument is valid and that that concrete argument is fallacious: he may not

know—or he may not interest himself in the fact—that this argument is a

syllogism in Barbara and that argument a case of afﬁrming the consequent;

but his dialectical technique, and his familiarity with his truths, will enable

him to detect falsity and fallacy.

That may seem an optimistic account of the prowess of the Platonic

dialectician; for it is difﬁcult to imagine that someone trained in Platonic

divisions will thereby acquire a general competence in logical matters. It is

indeed difﬁcult—but Plotinus does not imagine that a training in division

produces logical expertise. Rather, dialecticians allow that some parts of

general logic must be studied—and studied as being a propaedeutic to

dialectic. So dialecticians will in fact have done some general logic; and if

they can unmask fallacies and recognize syllogisms, that is not because they

are dialecticians and skilled in division but because they have studied logic.

The portrait of the logician is well drawn—at least insofar as Plotinus

expresses the essentially formal aspect of logical study. But why does he think

that logic, so understood, is merely a tool to be used by the philosopher

whereas dialectic is something more? True, Plotinus does not explicitly

say that logic is a tool, still less that it is nothing but a tool. But that

is plainly what he implies. Moreover, if logic is a tool for philosophers,

then that is because dialectic judges some parts or aspects of logic to be

useful: in other words, some bits of logic help us on the ascent to the

Idea of the Good. How might they do so? Might they, for example, aid

the dialectician in his divisions? Perhaps; but how exactly logic might

offer anything in the way of climbing-tackle Plotinus does not trouble to

describe.

452 When is a Syllogism not a Syllogism?

Even if Plotinus is right and logic is a useful dialectical tool, it will not

follow that logic is nothing but a tool: perhaps it is both a tool and also a

part—even an honourable part—of philosophy? After all, why should the

study of bare theorems be any less honourable than the study of the things

which exist? Or rather, is it not a false antithesis to set logical theorems against

truths about the world? The bare theorems of the logician are truths about

everything—and therefore about everything which exists.

As for dialectic, Plotinus explicitly afﬁrms that it is not a tool but a part,

and the honoured part, of philosophy. Yet for all that, he seems in fact

to characterize it as a tool or instrument—and to do so as soon as he has

established that it is a part:

So it is a part, the honoured part. For philosophy has other parts too—for example,

it studies nature, taking help from dialectic as the other arts make use of arithmetic.

(enn i iii 6 [1–3])⁹

Natural philosophy makes use of dialectic, just as other arts make use of

arithmetic: that is to say, although dialectic is declared an honoured part of

philosophy, it is also a tool of philosophy. And of course Plotinus actually

introduces dialectic as a way or method, and considers it exclusively as

something which helps us onward and upward; and he does nothing to

explain how it might also be a valuable study in its own right—how doing

long division on the model of the Sophist or the Statesman might be a

worthwhile occupation quite apart from its instrumental value in aiding us

to an understanding of the world of Ideas. Indeed, it is not easy to see how

dialectic—Plotinian dialectic—might have anything but instrumental value

for a Platonist. It is a curious fact that Plotinus himself never alludes to

dialectic outside Ennead i iii: he never breathes another word about what he

there claims to be the most honourable part of philosophy. I wonder if the

little essay on dialectic is anything more than lip-service to Plato?

THE STATUS OF LOGIC

However that may be, Plotinus’ remarks on dialectic and logic have a larger

context. Antiquity liked to divide philosophy into three parts: logic, physics,

⁹ μέρος οὖν τὸ τίμιον· ἔχει γὰρ καὶ ἄλλα φιλοσοφία· καὶ γὰρ καὶ περὶ φύσεως θεωρεῖ

βοήθειαν παρὰ διαλεκτικῆς λαβοῦσα, ὥσπερ καὶ ἀριθμητικῇ προσχρῶνται αἱ ἄλλαι τέχναι.

The Status of Logic 453

and ethics. No philosopher, so far as I know, ever doubted that ethics was a

genuine part of his domain. A few philosophers allegedly declared themselves

against physics, the subject being too deep or too elevated for merely human

minds to encompass. Several philosophers, and some schools of philosophy,

had their doubts about logic.

Thenatureandthescopeofthosedoubtswerevarious—andtheywere

sometimes, it may be suspected, rather vague. When, for example, Sextus is

discussing the parts of philosophy and their detractors, he observes that

Archelaus of Athens pursued physics and ethics, and with him some place Epicurus

too, on the grounds that he rejected logical theory.

(M vii 23)¹⁰

Archelaus was a contemporary of Socrates: if he did not pursue logic, that

was because no one had yet thought to invent the subject. But Epicurus—or

so the anonymous ‘some’ must have thought—positively repudiated the

subject. But what was it to repudiate a subject? Some scholars have supposed,

radically and quite implausibly, that Epicurus did not produce—or intended

not to produce, or was deemed not to have produced or not to have intended

to produce—arguments in favour of his philosophical doctrines: to repudiate

logic is to abjure reasoning in favour of direct insight. Other scholars have

supposed, equally implausibly, that Epicurus’ repudiation of logic consisted in

the thesis that logic is not an independent discipline, or that the study of logical

questions in abstraction from physics and ethics make no sense. And between

those two sorts of repudiation there is a whole spectrum of possibilities.

Again, the term ‘logic’ might be taken in more ways than one. Indeed,

in Greek there are three words—not one—to consider: ‘λογική’, ‘συλλο-

γιστική’, ‘διαλεκτική’. The term ‘λογική’ generally has a broad sense, espe-

cially when it is put on a level with ‘φυσική’and‘ἠθική’ and used to designate

one of the three parts of philosophy; for then it is concerned with everything

which pertains to λόγος—to reason and to language. If it includes everything

which we might count as logic, it also embraces epistemology, and linguistics,

and (sometimes at least) rhetoric. The word ‘συλλογιστική’ generally has a

narrow sense: it means something like ‘theory of inference’, or perhaps, yet

more narrowly, ‘theory of formal deductive inference’. In other words, ancient

syllogistic is roughly comparable to modern formal logic. As for ‘διαλεκτική’,

¹⁰ ᾿Αρχέλαος δὲ ὁ ᾿Αθηναῖος τὸ φυσικὸν καὶ ἠθικόν [sc μετήρχετο]· μεθ᾿ οὗ τινες καὶ τὸν

᾿Επίκουρον τάττουσιν ὡς τὴν λογικὴν θεωρίαν ἐκβάλλοντα.

454 When is a Syllogism not a Syllogism?

the term has different resonances in different contexts: for Plotinus—as we

have seen—and for Plato, it is an honourable method, the only method which

will lead to the Ideas and the really real world; in Aristotle, it is the method

or practice of arguing on the basis of reputable opinions; for the Stoics, it is

one of the two branches of λογική, the other being rhetoric; and in contexts

which are not philosophically partisan—in Sextus, for example—dialectic is

usually something like logic in a broadish sense of the word.

What, then, did Epicurus repudiate? Sextus says that, according to some,

he repudiated λογική. But inasmuch as ‘λογική’ there names one of the

three parts of philosophy, that is certainly false—to mention nothing else,

there was an elaborate Epicurean epistemology. Archelaus, we may suppose,

did no λογική at all. What the Epicureans lacked, or lacked interest in, was

συλλογιστική—although, as Philodemus’ work On Signs demonstrates, they

had a lively interest in certain forms of inference.

Logic was a constituent part of the Stoic philosophy. (Or at least, it was a

part of the orthodox Stoic philosophy; for some Stoics had had no time for

logic, or for some pieces or aspects of logic.) And it is universally agreed that

no Peripatetic ever repudiated logic in any sense or fashion. Nonetheless, the

Peripatetics did something which the orthodox Stoics did not do, and which

would not have shocked orthodox Epicureans.

Alexander opens his commentary on the Prior Analytics in this way:

The study of logic or syllogistic, which is now before us and under which fall probative

and dialectical and examinatory method—and also sophistical method—is a product

of philosophy. Some other sciences and arts also make use of it, but they take it from

philosophy, to which belong its discovery and its constitution and its most important

uses. Being a product of philosophy, it seems to some people to be in addition a part

of philosophy, whereas others say that it is not a part but a tool of philosophy.

(in APr 1.3–9)¹¹

Some people say this and some say that: who said what? and when? and so

what?

Later texts give names to Alexander’s anonymous partisans. According to

Ammonius, for example,

¹¹ ἡ λογική τε καὶ συλλογιστικὴ πραγματεία ἡ νῦν ἡμῖν προκειμένη, ὑφ᾿ ἣν ἥ τε ἀποδεικτικὴ

καὶ ἡ διαλεκτική τε καὶ πειραστικὴ ἔτι τε καὶ ἡ σοφιστικὴ μέθοδος, ἔστι μὲν ἔργον φιλοσοφίας,

χρῶνται δὲ αὐτῇ καὶ ἄλλαι τινές ἐπιστῆμαι καὶ τέχναι, ἀλλὰ παρὰ φιλοσοφίας λαβοῦσαι·

ταύτης γὰρ ἥ τε εὕρεσίς ἐστι καὶ ἡ σύστασις καὶ ἡ πρὸς τὰ κυριώτατα χρῆσις. οὖσα δὲ ἔργον

αὐτῆς τοῖς μὲν καὶ μέρος φιλοσοφίας εἶναι δοκεῖ, οἱ δὲ οὐ μέρος ἀλλ᾿ ὄργανον αὐτῆς φασιν

εἶναι.

The Status of Logic 455

the Stoics insist that logic should not only not be called a tool of philosophy—it

should not even be called a subpart, but rather a part; and some of the Platonists too

were of that opinion, because according to Plato logic is not a tool but a part—and

a most honourable part—of philosophy. But the Peripatetics say that it is a tool and

not a part.

(in APr 8.20–25)¹²

Ammonius’ pupil Philoponus ﬁnds three rather than two parties to the

dispute:

The Stoics assert outright that it is a part, co-ordinating it with the two other parts

of philosophy. The Peripatetics—that is to say, Aristotle’s followers—say that it is a

tool. The Academics, among them Plato, plainly say that it is both a part and a tool.

(in APr 6.21–24)¹³

No one doubts that the Peripatetics generally took logic to be a tool and

not a part of philosophy: Alexander argued for the view, which he took to

be Aristotle’s. The view was also found outside the Peripatetic circle: Galen

supports it; it may be discovered in Epictetus’ conversazioni; and Proclus and

his set adopted it. No one doubts that the Stoics generally took logic to be a

part of philosophy—although there were certainly dissident Stoics, on this

as on other points of doctrine.

Philoponus insinuates that the Stoics denied that logic was a tool of

philosophy—otherwise there is no contrast in his text between Stoics and

Academics. But the insinuation is false, and absurd: numerous texts state or

imply that logic, in Stoic eyes, was of the greatest philosophical utility. After

all, the Stoics

say that dialectic was invented to be as it were the arbiter and judge of the true and

the false.

(Cicero, Luc xxviii 91)¹⁴

How could such a science fail to have instrumental value? In any event, the

Stoics

¹² οἱ μὲν Στωϊκοὶ τὴν λογικὴν οὐ μόνον ὄργανον οὐκ ἀξιοῦσι καλεῖσθαι φιλοσοφίας, ἀλλ᾿

οὐδὲ μόριον τὸ τυχὸν ἀλλὰ μέρος. καὶ τινὲς δὲ τῶν Πλατωνικῶν ταύτης ἐγένοντο τῆς δόξης,

ὅτι κατὰ Πλάτωνα οὐκ ὄργανον ἡ λογικὴ ἀλλὰ μέρος καὶ τιμιώτατον μέρος ἐστὶν φιλοσοφίας.

οἱ δὲ Περιπατητικοὶ ὄργανον αὐτὴν λέγουσιν ἀλλ᾿ οὐ μέρος.

¹³ οἱ μὲν γὰρ Στωϊκοὶ ἄντικρυς μέρος αὐτὴν ἀποφαίνονται, τοῖς ἄλλοις δύο μέρεσι τῆς

φιλοσοφίας αὐτὴν ἀντιδιαιροῦντες· οἱ δὲ Περιπατητικοί, τουτέστιν οἱ ἀπὸ ᾿Αριστοτέλους,

ὄργανον· οἱ δὲ ἀπὸ τῆς ᾿Ακαδημίας, ὧν ἐστι καὶ Πλάτων, καὶ μέρος καὶ ὄργανον φαίνονται

λέγοντες.

¹⁴ dialecticam inventam esse … veri et falsi quasi disceptatricem et iudicem.

456 When is a Syllogism not a Syllogism?

say that the study of syllogisms is of the greatest utility; for it indicates what is

probative (which contributes greatly to the correction of opinions and to their

ordering and retaining) and it indicates a scientiﬁc grasp of things.

(Diogenes Laertius, vii 45)¹⁵

As for Philoponus’ Academics, they presumably took what was in fact the

Stoic view. Unless, of course, Philoponus is simply misreporting Plotinus’

view of the matter—as, in a different way, Ammonius does. For where

Ammonius refers to ‘some of the Platonists’ he is surely thinking, no doubt

at a remove, of Plotinus—and he is attributing to logic the features which

Plotinus denied to logic and ascribed to Platonic dialectic. I suspect that the

same Plotinian text lies behind Philoponus’ remarks: where Plotinus says or

implies that logic is a tool and dialectic a part, Philoponus turns this into the

thesis that logic was at once a tool and a part.

So all philosophers—or at any rate, all those philosophers who did not

repudiate logic—supposed that the subject had an instrumental value. Sextus

speaks quite generally when he remarks that

the logicians say that they have had recourse to the art of logic not simply in order to

know what can be inferred from what but principally in order to distinguish truths

and falsities by way of probative arguments.

(PH ii 247)¹⁶

That logic is a tool was not disputed among the logicians. The question was:

is logic also a part of philosophy?

When was the question ﬁrst raised? Muddle and confusion are the hallmark

of the late commentators, especially when it comes to historical information.

But we should not succumb to the brutal charm of nihilism and declare that

the whole debate on the status of logic was a myth. It is clear that the question

was discussed in the Peripatetic school; it is highly probable that some other

thinkers took up the issue; and it is possible that there was indeed something

which might be called a debate or a dispute.

¹⁵ εὐχρηστοτάτην δέ φασιν εἶναι τὴν περὶ τῶν συλλογισμῶν θεωρίαν· τὸ γὰρ ἀποδεικτικὸν

ἐμφαίνειν, ὅπερ συμβάλλεσθαι πολὺ πρὸς διόρθωσιν τῶν δογμάτων καὶ τάξιν καὶ μνήμην, τὸ

δ’ἐπιστημονικὸν κατάλημμα ἐμφαίνειν.—For ‘τὸ δ’ἐπιστημονικόν’ (Usener plus Gigante) the

MSS have ‘τὸ ἐπιστατικόν’.

¹⁶ ἐπὶ τὴν τέχνην τὴν διαλεκτικήν φασιν ὡρμηκέναι οἱ διαλεκτικοὶ οὐχ ἁπλῶς ὑπὲρ τοῦ

γνῶναι τί ἐκ τίνος συνάγεται, ἀλλὰ προηγουμένως ὑπὲρ τοῦ δι᾿ ἀποδεικτικῶν λόγων τὰ

ἀληθῆ καὶ τὰ ψευδῆ κρίνειν ἐπίστασθαι.

The Use of Logic 457

When did the matter get its ﬁrst airing? The commentators ascribe a

position in the debate to Aristotle; but although the ascription is not merely

imaginative, there is no evidence that Aristotle had ever given the matter much

thought. The Stoics, from the ﬁrst, seem to have divided philosophy—or

the account of philosophy—into logic and physics and ethics; and they are

generally supposed to have taken the tripartition over from one or another of

Plato’s followers. But you may speak of logic as a part of philosophy without

having wondered what its status really was. And in fact, no author earlier

than Alexander unequivocally adverts to the question of status.

One text, however, may plausibly be invoked. In his account of Aristotle’s

philosophy, Diogenes Laertius remarks that

to the theoretical part of philosophy there belong physics and logic—logic having

been elaborated not as a part of a whole but as a tool.

(v 28)¹⁷

That remark presupposes if not a debate at least some reﬂexion on our

question; and although Diogenes himself is later than Alexander, the source

which he used for his account of Aristotelianism was certainly earlier than

Alexander—and it may well have been Hellenistic.

THE USE OF LOGIC

But of what possible interest to us can any of that old and arid stuff be?

If logic is a part of philosophy, then—as Alexander puts it—it is studied

‘in order to gain knowledge of the truths which it contains in itself’ (in APr

3.12–13).¹⁸ If it is a tool of philosophy—and also of certain other arts and

sciences—what instrumental function does it serve? No doubt it has several

uses; for example,

if logic is studied in order to exercise the mind with a view to making discoveries in the

various parts of philosophy, then for that reason too it will have the status of a tool.

(in APr 3.10–12)¹⁹

¹⁷ τοῦ δὲ θεωρητικοῦ [sc λόγου] τόν τε φυσικὸν καὶ λογικόν, οὗ τὸ λογικὸν οὐχ ὡς ὅλου

μέρος, ἀλλ᾿ ὡς ὄργανον προσηκριβωμένον.

¹⁸ διὰ τὴν τῆς ἐν αὐτῇ ἀληθείας γνῶσιν.—The received text has ‘αὐτοῖς’for‘αὐτῇ’.

¹⁹ ἔτι εἰ σπουδάζοιτο ὡς γυμνάσιον τῆς διανοίας πρὸς τὴν εὕρεσιν τῶν ἐν τοῖς μέρεσι τῆς

φιλοσοφίας ζητουμένων, καὶ οὕτως ἂν τὴν τοῦ ὀργάνου χώραν ἔχοι.

458 When is a Syllogism not a Syllogism?

But of the various uses for logic which were or might have been mooted, one

was dominant and determinant. Alexander again:

If becoming like God is the greatest good for men, and if men attain this by study

and knowledge of truth, and if knowledge of truth is attained by proof, then proof

will justly be deemed most honourable and most worthy of study—and so too for

that reason will syllogistic, since a proof is a sort of syllogism.

(in APr 6.8–12)²⁰

Proofs are syllogisms: logic or syllogistic has as its aim the production of

proofs—and therein lies its utility and its instrumental value.

Galen took the same view as Alexander. Thus, referring to certain types

of argument with which—so he says—the Stoics were much occupied, he

remarks that

all the construction of such syllogisms is no small waste of time on a useless object—as

Chrysippus himself bears witness in his deeds; for nowhere in all his writings does he

make use of such syllogisms to prove a doctrine.

(PHP v 224)²¹

If an argument cannot be called upon to formalize a proof, it is useless, and

thinking about it is a waste of time. There are a dozen comparable passages

in Galen’s writings.

Galen swore allegiance to no school. Alexander professed the Peripatetic

philosophy; and the view which Galen and he shared was, he claimed, the

view of Aristotle himself. The ﬁrst words of the Prior Analytics are these:

First, we must say what our inquiry is about and with what it is concerned—it is

about proof and concerned with probative knowledge.

(APr 24a10–11)²²

Alexander comments:

²⁰ εἰ δὴ τὸ θεῷ ὁμοιοῦσθαι μέγιστον ἀγαθὸν ἀνθρώπῳ, τοῦτο δ᾿ αὐτῷ διὰ θεωρίας τε

καὶ τῆς τἀληθοῦς γνώσεως περιγίνεται, ἡ δὲ τἀληθοῦς γνῶσις δι᾿ ἀποδείξεως, δικαίως ἂν

πλείστης τιμῆς ἀξιοῖτο καὶ σπουδῆς, διὰ δ᾿ αὐτὴν καὶ ἡ συλλογιστική, εἴ γε ἡ ἀπόδειξις

συλλογισμός τις.

²¹ …πρὸς τῷ καὶ περιεργίαν εἶναι οὐ μικρὰν ἀχρήστου πράγματος ἅπασαν τὴν τῶν

τοιούτων συλλογισμῶν πλοκήν, ὡς αὐτὸς ὁ Χρύσιππος ἔργῳ μαρτυρεῖ μηδαμόθι τῶν ἑαυτοῦ

συγγραμμάτων εἰς ἀπόδειξιν δόγματος ἐκείνων δεηθεὶς τῶν συλλογισμῶν.

²² πρῶτον εἰπεῖν περὶ τί καὶ τίνος ἐστὶν ἡ σκέψις, ὅτι περὶ ἀπόδειξιν καὶ ἐπιστήμης

ἀποδεικτικῆς.

The Use of Logic 459

At the beginning of the study he announced what its goal and aim are, namely proof

and probative knowledge. Hence whatever makes no contribution to those things

will not be appropriate to the study before us.

(in APr 20.24–27)²³

The subject of the Analytics as a whole is the theory of proof, so that the

syllogistic theory developed in the Prior Analytics has the theory of proof as

its sole aim or goal. And Alexander inferred that, for Aristotle, logic has value

just insofar as it serves the needs of proof, just insofar as philosophers and

scientists may make use of logic in order to prove their theorems.

That is how the corpus of Aristotle’s logical writings got its traditional name:

logic is a tool or ὄργανον,andthecorpus is therefore Aristotle’s Organon.

Aristotle himself certainly thought that proofs are a sort of syllogism—indeed,

hedeﬁnesaproofasa‘cognitivesyllogism’(APst 71b17–18).²⁴ He also

thought—and thought he could prove—that

it is necessary that every proof and every syllogism come about through one of the

three ﬁgures we have described.

(APr 41b1–3)²⁵

That is to say, the syllogistic theory which Aristotle elaborates in the Prior

Analytics is sufﬁcient for all the probative requirements of the sciences.

So Aristotle ascribes instrumental value to logic and to syllogistic; and

its instrumental value—or at any rate a part of its instrumental value—is

determined by its essential contribution to the production of scientiﬁc proofs.

But it does not follow that, in Aristotle’s view, the sole reason for studying

logic is to satisfy the needs of probative science; and despite Alexander and

his friends, it is difﬁcult to read through the Analytics and imagine that their

author saw no value in the work but an instrumental utility and no purpose

but the production of probative structures.

However that may be, according to the utilitarian view of logic which Alex-

ander and Galen and many others adopted, every proof is a syllogism and every

syllogism is a potential proof. The point can perhaps best be put as follows.

²³ αὐτὸς ἀρχόμενος τῆς πραγματείας τί τέλος αὐτῆς καὶ σκοπός ἐστι προεῖπεν· ἀπόδειξις

γὰρ καὶ ἐπιστήμη ἀποδεικτική· ὥσθ᾿ ὅσα μηδέν εἰς ταῦτα συντελεῖ, οὐκ ἂν οἰκεῖα τῆς

προκειμένης εἴη πραγματείας.

²⁴ ἀπόδειξιν δὲ λέγω συλλογισμὸν ἐπιστημονικόν.

²⁵ πᾶσαν ἀπόδειξιν καὶ πάντα συλλογισμὸν ἀνάγκη γίνεσθαι διὰ τριῶν τῶν προειρημένων

σχημάτων.