De ortu logicae.
Why Logic Was Needed
Logic was discovered last because proper reasoning requires a truthful method of speaking, and without it even the ancients were deceived by confused words and meanings.
Now that we've traced the origins of the theoretical, practical, and mechanical branches, it remains to investigate the origin of logic as well—which I count as the last precisely because it was discovered last. The other branches had been discovered earlier, but logic also needed to be discovered, since no one can discuss things properly unless they've first recognized the correct and truthful method of speaking. As Boethius says: when the ancients first devoted their effort to investigating the natures of things and the qualities of customs, they were often led astray, because they had no distinction between words and understandings—as happens in many cases with Epicurus, who thinks the world consists of atoms and falsely claims that pleasure is what is honorable.1
The Error of Confusing Reason with Reality
Those who neglect logical disputation inevitably err, because unlike numbers, arguments do not guarantee truth about things unless one first learns to distinguish sound reasoning from mere plausibility.
It's clear, then, that this happened to this person and to others for the very reason that, through inexperience in disputing, whatever they had grasped through reasoning, they thought carried over into the things themselves as well. This, however, is a serious error. Things don't behave in reasonings the way they do in numbers. In numbers, whatever comes out correctly on the calculating fingers — that result, without question, must also hold in the things themselves. So if the calculation yields a hundred, then a hundred things, too, must necessarily be subject to that number. But this doesn't hold equally in disputation. Whatever course a line of argument happens to take isn't thereby fixed in nature. So those who set aside the knowledge of disputing and still try to investigate the nature of things are bound to be misled. For unless one first comes to know which line of reasoning holds a true path in disputing and which merely seems likely, and can recognize which claims are trustworthy and which may be suspect, the uncorrupted truth of things simply can't be found through reasoning alone.
The Birth of Logical Discipline
Because the ancients fell into contradictory errors, the logical discipline arose to examine disputation itself and to teach the nature of words and understandings as the first step in philosophy.
Since, then, the ancients often fell into many errors, devising in their disputes certain things that were both false and contradictory, and since it seemed impossible that, when contradictory conclusions were drawn on the very same matter, both could be true — things which reasoning, at odds with itself, had concluded — and it was unclear which line of reasoning ought to be trusted, it seemed best to first examine the true and complete nature of disputation itself. Once that was understood, the further question could then be considered: whether what is discovered through disputation is truly comprehended and can be understood. From this, then, the expertise in logical discipline advanced — a discipline that prepares the methods of disputing and the very ways of distinguishing between lines of reasoning, so that we may recognize which reasoning is at one time true and at another false, which is always false, and which can never be false. In time, this discipline is indeed the last, but in order it is the first. For this is the first text to be read by those beginning philosophy, because in it are taught the nature of words and of understandings, without which no philosophical treatise can be rationally explained.
What the Name 'Logic' Means
Logic derives from logos, meaning speech or reason, and is the rational science of speaking and disputing that was eventually formalized as the fourth branch of knowledge.
Logic takes its name from the Greek logos, a word that carries a double meaning. For logos means speech or reason, and from this logic can be called the science of speech or the rational science. Rational logic, which is also called disputative, includes dialectic and rhetoric. The logic of speech is a kind that relates to grammar, dialectic, and rhetoric, and it includes the disputative within itself. This is the logic of speech, which we list as the fourth branch, after the theoretical, the practical, and the mechanical. Nor should you suppose that logic — that is, the logic of speech — is so called because there were no speeches before it was invented, as though people had not previously exchanged conversation with one another. There were already common speeches and writing too, but as yet no systematic method for speech and writing had been brought into a formal discipline. As yet, no proper rules for speaking or debating had been laid down.
From Practice to Formal Discipline
All branches of knowledge first existed in practice before being shaped into formal disciplines by fixed rules and precepts.
For all branches of knowledge existed in practice before they existed as formal disciplines. But then people began to consider that practice could be shaped into a formal discipline, and that what had once been loose and undisciplined could be held in check by fixed rules and clear precepts — and so, as noted earlier, they set about reducing to systematic form a body of custom that had arisen partly by chance and partly from natural impulse, correcting whatever faulty practice had introduced, supplying what was lacking, and cutting away what was excessive, and from that point on prescribing definite rules and precepts for each area in particular.
The Arts Before Themselves
Grammar, dialectic, rhetoric, arithmetic, music, geometry, and astronomy all emerged as formal arts after their corresponding practices already existed.
That's how all the arts got their start: as we run through them one by one, we find this to be true. Before there was such a thing as grammar, people were already writing and speaking. Before there was such a thing as dialectic, they were already distinguishing the true from the false by reasoning. Before there was such a thing as rhetoric, they were already handling civil laws. Before there was such a thing as arithmetic, they already had the knowledge of counting. Before there was such a thing as music, they were already singing. Before there was such a thing as geometry, they were already measuring fields. Before there was such a thing as astronomy, they were already tracking the movements of the stars to mark off the seasons.
The Four Sciences and the Soul
The four sciences—theoretical, practical, mechanical, and logic—are recapitulated and linked to the soul's fourfold number, a dignity honored even in ancient oaths.
But the arts did come, and although they took their beginning from practice, they are improved by practice nonetheless. This would be the place to set out who the inventors of each of the arts were, when they lived, and where, and how the disciplines got their start through them, but I want first to distinguish them from one another by a prior division of philosophy. So it's necessary to briefly recap what was said above, to make a smoother transition to what follows. We've said there are only four sciences that contain all the rest: that is, the theoretical, which labors in the contemplation of truth; the practical, which considers the discipline of morals; the mechanical, which manages the activities of this life; and logic as well, which provides the knowledge of speaking correctly and disputing sharply. So this fourfold number of the soul can not unreasonably be understood — the one the ancients had adopted for their oaths out of reverence for its dignity. Hence too that saying:
Returning to the Definition of Philosophy
The chapter closes by invoking the fourfold soul and promising to show how all these sciences are contained within philosophy through its definition.
Through him who gave to our soul its fourfold number. We'll now briefly show, by going over the definition of philosophy again, how these things are contained within philosophy, and again, what things philosophy itself contains under it.
Read the original Latin
Postquam igitur theoricae et practicae et mechanicae ortum demonstravimus, superest logicae quoque originem investigare, quam idcirco ultimam annumero quia postremo inventa est. ceterae prius repertae fuerant, sed necesse fuit logicam quoque inveniri, quoniam nemo de rebus convenienter disserere potest. nisi prius recte et veraciter loquendi rationem agnoverit. nam sicut dicit Boethius: Cum primitus antiqui circa naturas rerum et morum qualitates investigandas operam impenderent, necesse fuit saepe falli eos, quia vocum et intellectuum discretionem non habebant, ut in multis evenit Epicuro, qui atomis mundum consistere putat et honestum voluptatem mentitur.
Hoc autem idcirco huic atque aliis accidisse manifestum est, quoniam per imperitiam disputandi, quidquid ratiocinatione comprehenderant, hoc in res quoque ipsas evenire arbitrabantur. hic vero magnus est error. neque enim sese res ut in numeris, ita etiam in ratiocinationibus habent. in numeris enim quidquid in digitis recte computantis evenerit, id sine dubio in res quoque ipsas evenire necesse est, ut si ex calculo centum contigerit, centum quoque res illi numero subiectas esse necesse est. hoc vero non aeque in disputatione servatur. neque enim quidquid sermonum decursus invenerit, id in natura fixum tenetur. quare necesse est falli, qui abiecta scientia disputandi, de rerum natura perquirerent. nisi enim prius ad scientiam venerit, quae ratiocinatio veram teneat semitam disputandi, quae verisimilem, et agnoverit quae fida, quae possit esse suspecta, rerum incorrupta veritas ex ratiocinatione non potest inveniri.
cum igitur veteres saepe multis lapsi erroribus, falsa quaedam sibi et contraria in disputatione colligerent, atque id fieri impossibile videretur, ut de eadem re contraria conclusione facta, utraque essent vera, quae sibi dissentiens ratiocinatio conclusisset, cuive ratiocinationi credi oporteret, esset ambiguum, visum est prius disputationis ipsius veram atque integram considerare naturam. qua cognita, tum illud quoque, quod per disputationem inveniretur, an vere comprehensum esset, posset intelligi. hinc igitur profecta logicae peritia disciplinae, quae disputandi modos atque ipsas ratiocinationes internoscendi vias parat, ut quae ratiocinatio nunc quidem vera, nunc autem falsa, quae vero semper falsa, quae numquam falsa possit agnosci. haec tempore quidem postrema est, sed ordine prima. haec enim incohantibus philosophiam prima legenda est, propterea quod in ea docetur vocum et intellectum natura, sine quibus nullus philosophiae tractatus rationabiliter explicari potest.
Logica dicitur a Graeco logos, quod nomen geminam habet interpretationem. dicitur enim logos sermo sive ratio, et inde logica sermocinalis sive rationalis scientia dici potest. logica rationalis, quae dissertiva dicitur, continet dialecticam et rhetoricam. logica sermocinalis genus est ad grammaticam, dialecticam atque rhetoricam, et continet sub se dissertivam. et haec est logica sermocinalis, quam quartam post theoricam, practicam, mechanicam annumeramus. nec putandum est ideo logicam, id est, sermocinalem dici, quod ante eius inventionem nulli fuerint sermones, et quasi homines mutuas locutiones prius non habuerint. erant prius et sermones communes et litterae, sed nondum ratio sermonum et litterarum in artem redacta fuerat. nulla adhuc recte loquendi vel disputandi praecepta data erant.
omnes enim scientiae prius erant in usu quam in arte. sed considerantes deinde homines usum in artem posse converti et quod vagum fuerat et licentiosum prius certis regulis et praeceptis posse restringi, coeperunt, ut dictum est, consuetudinem quae partim casu, partim natura exorta fuerat, ad artem reducere, id quod pravum usus habebat emendantes, quod minus habebat supplentes, quod superfluum habebat resecantes, et de cetero singulis certas regulas et praecepta praescribentes.
Huiusmodi fuit origo omnium artium; hoc per singula currentes verum invenimus. priusquam esset grammatica et scribebant et loquebantur homines. priusquam esset dialecta, ratiocinando verum a falso discernebant. priusquam esset rhetorica, iura civilia tractabant. priusquam esset arithmetica, scientiam numerandi habebant. priusquam esset musica, canebant. priusquam esset geometria, agros mensurabant. priusquam esset astronomia, per cursus stellarum discretiones temporum capiebant.
sed venerunt artes, quae licet ab usu principium sumpserint, usu tamen meliores sunt. hic locus esset exponere qui fuerint singularum artium inventores, quando extiterint aut ubi, aut quomodo per eos disciplinae exordium sumpserint, sed volo quadam prius philosophiae divisione singulas a se invicem discernere.
Oportet ergo breviter recapitulare quae supradicta sunt, ut facilior fiat transitus ad sequentia. quattuor tantum diximus esse scientias, quae reliquas omnes continent, id est, theoricam, quae in speculatione veritatis laborat, et practicam, quae morum disciplinam considerat, et mechanicam, quae huius vitae actiones dispensat, logicam quoque, quae recte loquendi et acute disputandi scientiam praestat. hic itaque non absurde ille quaternarius animae intelligi potest, quem ob reverentiam sui antiqui in ius iurandum asciverant. unde et illud dictum est:
Per qui nostrae animae numerum dedit ille quaternum.
hae qualiter sub philosophia contineantur, et rursum quas sub se contineant, repetita breviter definitione philosophiae ostendemus.
Notes
- 1 ↩The Latin 'honestum voluptatem mentitur' is rendered 'falsely claims that pleasure is what is honorable' — the predicate accusative honestum = 'what is honorable' or 'the honorable', with voluptatem as the subject of the indirect statement. The sense is that Epicurus misrepresents pleasure as the highest good.
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