Chapter VI: Italian Text (6)

Theologians (says Weyer in conclusion) may object that he is only a physician and bid him keep to his last. He can only reply that St. Luke was a physician, and that he is one of those who hope by the mercy of God and grace of Christ to attain that royal priesthood of which St. Paul and St. John speak. Finally he is ready to submit all he has said to the judgement of the Church, and to recant any errors of which he may be convicted.

The Church answered by putting his name on the _Index_ as an _auctor primae classis_, that is, one whose opinions are so dangerous that none of his works may be read by the faithful without special permission, while his book was solemnly burnt by the Protestant University of Marburg.[338] The Duke of Alva, then engaged in his notorious work in the Netherlands, used his influence to get Weyer removed from his position at the court of Cleves. In this he was aided by the duke’s increasing melancholia and ill health, which were considered by many a judgement upon him for his protection of Weyer and neglect of witch-burning. In 1578 Weyer resigned his post to his son Galen, and in 1581 witch-hunting commenced in the duchy of Cleves. Weyer, however, as befitted the chivalrous defender of outraged womanhood, enjoyed the friendship and protection of Countess Anna of Techlenburg, at whose residence he died, 1588, aged seventy-two.

The work on _The Deceptions of Demons_ has been aptly compared to a torch thrown out into the darkness, which for a moment brightly illumes a small space and then disappears. It made a temporary sensation, and was welcomed by a few of the more enlightened spirits of the time; it saved the lives of some unfortunate women (being successfully quoted the very year after publication in defence of a young woman at Frankfort, who confessed she had flown through the air and had intercourse with the devil), and it marks the beginning of an open and persistent opposition to the witch mania. Spee also has a curious story showing the influence of Weyer’s book:

‘A great prince invited two priests to his table, both men of
learning and piety. He asked one of them whether he thought it
right to arrest and torture persons on the evidence of 10 or 12
witches. Might not the devil have deceived them in order to make
rulers shed innocent blood, as certain learned men had lately
argued, “thereby causing us pangs of conscience”? The priest
stoutly maintained that these pangs were needless, for God would
never allow the devil to bring innocent men to a shameful and
horrible death in this way; and so he (the prince) might continue
the witch trials as usual. He persisted in this, till the prince
said, “I am sorry, my father, you have condemned yourself and
cannot complain were I to order your immediate arrest, for no less
than 15 persons have sworn you were with them at the witch dances”,
and he produced the records of their trials in proof. Then the good
man stood like butter in the sun in the dog-days, and had nothing
more to say for himself.’[339] #/

But it had little effect on the superstition itself, which reached its height during the following half-century; and the author is compelled by his religious beliefs to admit so much that his position is hardly tenable. Indeed, his premisses had already been granted by the witch-hunters themselves. The jurist Molitor, for instance, admits that much witchcraft is imaginary and due to the deceptions of demons, but while the physician argues that these deceptions are rendered possible by disease, and are themselves largely of the nature of disease, so that the victims deserve pity and medical treatment rather than burning, the lawyer asserts that a person can only be so deceived by his free will, and therefore a woman who believes she has made a compact or had intercourse with the devil is as deserving of punishment as if she had actually done so.[340]

Just over a century after the appearance of Weyer’s book (1664)

‘Sir Thomas Brown of Norwich, the famous physician of his time,
was desired by my Lord Chief Baron [Hale] to give his judgement
[in a case of witchcraft]. And he declared that he was clearly of
opinion That the Fits were natural, but heightened by the devil
co-operating with the malice of the witches at whose instance he
did the villanies. And he added, That in Denmark there had been
lately a great Discovery of Witches, who used the very same way of
afflicting persons by conveying pins into them.’

The jury ‘having Sir Thomas Brown’s Declaration about Denmark for their encouragement, in half an hour brought them in guilty.... They were hanged maintaining their innocence.’[341]

Had Brown been better acquainted with _The Deceptions of Demons_ he might have hesitated to make that ‘Declaration about Denmark’, but Weyer’s early opponent, Bishop Binsfeld, has no difficulties. Quoting Origen (in Matt. xvii. 15) he exclaims, ‘Physicians may say what they like, we who believe the Gospel hold that devils cause lunacy’ and many other diseases.[342] But for a demon to cause disease or do other harm, two things are requisite, the permission of God and the free will of some malicious person, witch, or sorcerer. The physician, Weyer, has denied the possibility of a compact with the devil, but is easily refuted by Scripture and Church authority. Did not the devil try to make a compact with Christ Himself?[343] Similarly he has no difficulty in showing that the Hebrew word for witch means much more than ‘poisoner’, and, given the almost universal beliefs of the age, it must be admitted that Brown and the bishop have the best of the argument.

In the opening chapter of his well-known work on rationalism, Lecky says that the decline of the belief in witchcraft ‘presents a spectacle not of argument and conflict, but of silent evanescence and decay’; it was ‘unargumentative and insensible’. Scot’s work ‘exercised no appreciable influence’, and, so far as the result was concerned, he, Weyer, and their like might as well have kept quiet and waited for the change to be effected by ‘what is called the spirit of the age’, that is, ‘a gradual insensible yet profound modification of the habits of thought’ due to ‘the progress of civilization’. This theory has been ably criticized elsewhere.[344] The truth it contains seems to be that argument would not have sufficed to change public opinion about witchcraft, without the aid of changes in other matters, and especially the development and success of scientific investigation. Such discoveries as the motion of the earth and circulation of the blood, when generally accepted (which was not till late in the seventeenth century), showed that the learned as well as the vulgar might be utterly mistaken in important beliefs supported by apparently good evidence, and that scientific methods of attaining truth differed widely from those of the witch-hunters.

The progress of civilization by practically abolishing the use of torture would alone have immensely diminished the number of victims, and of those ‘confessions’ on which the belief was fed. To use military language, the witch mania was an ugly and formidable redoubt connected with other forts and entrenchments. It suffered somewhat from the bombardment by Weyer and Scot, but could only be finally demolished by a general advance of the forces of science and civilization. But if every one had trusted to ‘the spirit of the age’ rather than disturb his neighbours’ beliefs, we might still be burning our grandmothers.

Though born in what is now Holland and educated in France, German writers claim Weyer as their countryman and compare him with Martin Luther. The monk of Wittenberg is indeed a fine figure with his ‘Here stand I; I cannot otherwise, God help me!’ But he had half Germany behind him; both princes and populace were ready to protect him. Weyer stood practically alone, and if he escaped being burnt by jurists and theologians, had a fair chance of being lynched by an enraged mob as a sorcerer and protector of witches. There was little to save him from torture and death but the strength of mind of Duke William of Cleves, who came of an insane family and already showed signs of melancholia.

Weyer was happily spared such a trial of his fortitude, but none the less does he deserve our admiration as the chivalrous champion of womanhood, who first, with vizor up and lance in rest, greeted, alas! not, like the knights of legend, by prayers and blessings but by threats and imprecations, went forth to do open battle with the hideous monster which had so long tortured and slain the innocent and helpless.

MS. MARSH 379 fo. 73]

THE ‘TRACTATUS DE CAUSIS ET INDICIIS MORBORUM’

كتاب الاسباب والعلامات

ATTRIBUTED TO MAIMONIDES

By Reuben Levy

Among modern authorities on Arabian medicine, the opinion has been widely held that the position of Maimonides as a medical writer must depend mainly upon an unpublished work from his hand, known as the _Tractatus de Causis et Indiciis Morborum_.[345] It is here sought to demonstrate that the Bodleian MS. (Marsh 379), hitherto regarded as containing this work, is in reality by another author, while the Paris MS. (Bibliothèque Nationale, Ancien Fonds 411),[346] the only other alleged copy of the _Tractatus de Causis et Indiciis Morborum_, contains in fact no such work. Moreover, evidence will be adduced showing that it is not probable that Maimonides composed a treatise of this scope.

For their information concerning the _Tractatus_, the modern bibliographers evidently rely entirely on entries in the catalogues of the respective libraries. The 1739 Catalogue of Arabic and Hebrew MSS. in the Bibliothèque Nationale contains the following entry:[347] ‘Codex bombycinus, Aleppo in bibliothecam Colbertinam anno 1673 illatus, quo continetur R. Mosis Maemonidae de morborum causis et illorum curatione tractatus, Arabice, charactere Hebraico.’ Careful examination of the manuscript disclosed the fact that it contained no fewer than four works of Maimonides, viz. on Poisons,[348] on Asthma,[349] the _Tractatus de Regimine Sanitatis_,[350] and the _Tractatus de Morbo Regis Aegypti_,[351] all bound together in confusion.[352] All these are known to be by Maimonides, and there is nothing besides them in the volume.

There has always been a good deal of confusion about the works _de Regimine Sanitatis_ and _de Morbo Regis Aegypti_. The former is variously known as _de Regimine Sanitatis, de Cibo et Alimento, de Dietetica_, ‘the letter to the Sultan’, or as ‘the Consultation concerning (the Sultan) Al Afḍal’.[353] The latter also has a number of titles, such as _de Causis Accidentium,[354] de Morborum Causis et Curatione_, and _Responsum ad Regem Raqqa_, in addition to its title of _de Morbo Regis Aegypti_. In 1514, in Venice the two treatises were printed together in Latin as one work.[355]

Leclerc[356] has made confusion worse confounded by saying that ‘ce que l’on a désigné sous les titres, _De Morbo Regis Aegypti, De Causis Accidentium, De Causis et Indiciis Morborum, De Cibo et Alimento_, ne sont autre chose que tout ou partie du même ouvrage’.[357] No doubt he was led into making this statement partly by the fact that Wüstenfeld[358] gives the title of _de Causis et Indiciis Morborum_ both to the Bibliothèque Nationale MS. (which Leclerc knew as _de Causis Accidentium_) and to the Bodley MS.

The entry concerning the latter in Uri’s Bodleian Catalogue of 1787[359] reads as follows:

‘Codex bombycinus, anno Hegirae 765, Christi 1363 exaratus, folia
116 implens. Comprehendit succinctum de omnium corporis humani
morborum causis, signis et remediis tractatum ab Ibn Hobaish
Hierosolymitano ex Hebraica lingua in Arabicam conversum, cui
sectiones sex supra centum sunt. Initium fit a morbis capitis;
finis in elephantiasi. Composuit Musa Ben Maimun Alcortubi,
Israelita. [Marsh 379.]’

The MS. bears upon one of its pages the title

هذا كتاب الاسباب والعلامات الحكيم
’موسى بن ميمون القرطبي الاسرايلي

‘This is the book of the causes and symptoms, by the Doctor Mûsa ibn Maimûn the Cordovan, the Israelite.’ (Plate XLI.)

As a matter of fact it is no such thing. This title, together with an extra title-page and colophon in the same hand, is a much later addition to the MS., which also has a fragment of some other medical work--at present unidentified--bound up with it. The folios of the MS. which deal with the _Tractatus_ have been bound together in extreme disorder, but examination of them has shown that they really form a fragment of the second book of المختار قي الطبّ, the _Delectus de Medicina_, by مهذب الدين ابو الحسن على بن احهد البغدادي, Muhaḏḏib ed Din Abu’l Hasan Ali Ibn Aḥmad of Bagdad.[360]

Ibn Abi ‛Uṣaibia (1203-1269)[361] gives a life of this writer and a list of his works, which includes the _Delectus de Medicina_. According to him, Muhaḏḏib ed Din was born at Bagdad in A.H. 515 (= A.D. 1121), and after studying medicine and philosophy settled at Mosul. Later he became the physician of the Shah Arman, chieftain of Khalāt on Lake Van in Armenia, in whose service he amassed great wealth. He completed the _Delectus_ at Mosul in the year A.H. 560 (= A.D. 1164), and died there in A.H. 610 (= A.D. 1213), with the reputation of being first physician of his time.

Another fragment of the same work of Muhaḏḏib ed Din, which includes most of the contents of the Bodleian MS., besides a good deal of material which has been lost from the latter, exists in the British Museum.[362] The Leyden Library contains a unique copy of the work in three books. This is claimed to be complete by the Catalogue of the library,[363] although Bar Hebraeus [1226-1286]--Catholicus of the Jacobite (Monophysite) Church[364]--says that the work ran into four parts.[365] The three books of the Leyden MS. treat (i) of generalities (i.e. Anatomy, Physiology, and the general causes of disease), (ii) of medicaments, and (iii) of particular diseases and their treatment.

The Bodleian and British Museum MSS. contain part of the third book, which was probably in general use by itself as a dictionary of medicine. The British Museum copy has only lost the earlier chapters of this third part, but the Bodleian MS., although possessing a few more chapters at the beginning, is far less complete in the other portions.[366]

Wüstenfeld and the bibliographers that followed him have evidently derived their information concerning these MSS. from the catalogues of the Bodleian Library and of the Bibliothèque Nationale. No mediaeval bibliographer has up to the present been found who mentions this book of Maimonides.[367] Wüstenfeld’s usual authority for his statements is the great thirteenth-century medical biographer, Ibn Abi ‘Uṣaibia. But, though the latter gives a life of the Hebrew physician and a list of his writings,[368] he makes no mention of the _Tractatus de Causis et Indiciis Morborum_. Moreover, this _Tractatus_ has no place in Haji Khalfa’s admirable bibliography of Arabic works, which contains notices of four books bearing the title _De Causis et Indiciis Morborum_, not one of which is by Maimonides. Lastly, neither the historian Al Qifty in his _Classes philosophorum et astronomorum et medicorum_,[369] nor Bar Hebraeus, who is said to have plagiarized him,[370] notice the work in their sketches of the physician’s life.

The Bodleian MS. alleged to contain the _Tractatus_ is one of a collection of over seven hundred volumes bequeathed to the library on his death, November 2, 1713, by Narcissus Marsh, Archbishop successively of Cashel, Dublin, and Armagh. Most of his Oriental MSS. had been procured for him either in the East by Robert Huntington, Bishop of Raphoe and chaplain to the English merchants at Aleppo, or at the sale of Golius’s library at Leyden in October 1696.[371] Golius was a Dutch orientalist, born at Leyden in 1596. He studied medicine and Oriental languages at the University of Leyden, and after leaving it he accompanied a French embassy to Morocco in 1622. He remained in Morocco for two years, and while there collected various MSS. On his return in 1624 he was appointed to the Chair of Arabic at Leyden, but was allowed a period of leave for travel in the East before taking up his appointment. He took with him a grant of money for the purchase of MSS., and these to the number of over two hundred are now deposited in the University Library at Leyden. On several occasions during his travels in Arabia attempts were made by Arab chiefs to detain him for his medical knowledge, but he returned safely and later wrote a number of works mainly concerned with Arabic. He died in 1667.

Among the MSS. which Golius himself procured for the Leyden Library was that of the _Delectus_. It is at least unlikely therefore that such a profound Arabist, who was also a medical man, would have bought the Bodley fragment for a genuine work of Maimonides; the primary responsibility for the error thus probably rests with Huntington. However that may be, it was Uri, in his catalogue of the Bodleian MSS., who first published the error, and from him it was passed on to the modern bibliographers.

John Uri was a Hungarian who had studied Oriental literature under Schultens at Leyden, and was recommended to Archbishop Secker for the purpose of cataloguing the Bodleian Oriental MSS., by Sir Joseph Yorke, then ambassador in the Netherlands.[372] Many years were occupied in the preparation of the work, which appears to have commenced in 1766 and was not completed till 1787. In spite of the length of time which Uri occupied in his task, his successor, Pusey, found sufficient errors in it to fill sixty closely printed pages. In his preface to the second volume of the Catalogue, issued in 1835,[373] Pusey complains ‘Urius vero MSS. haud raro negligenter exscripsit’, and says that on re-examination of Uri’s work he discovered, ‘besides the errors which Uri himself would have admitted, that nearly all the purchasers of these books, Pocock alone excepted, had had spurious works foisted on them by wily Orientals. He therefore looked through all the books which Uri had enumerated, excepting the more common ones, to see if they corresponded to their titles or not. By doing this he discovered various irregularities. In some cases the titles had been covered over with paper or obliterated with ink, or practically erased with a knife. In others, by slight changes in the authors’ names, more famous people were indicated as responsible for the works. Lastly, by changing the pagination in some of the volumes fragments were represented as complete works, and a few pages of one work were even occasionally sewn on at the beginning of another.’[374]

Uri’s errors will be the more readily condoned when it is remembered that he did not specialize on the Arabic MSS. alone, and that his work seeks to catalogue, _for the first time_, a two hundred years’ accumulation of Oriental MSS., including Hebrew, Aramaic, Syriac, Aethiopic, Arabic, Persian, Turkish, and Coptic writings. Nevertheless, Uri’s entry with reference to the present MS. deserves some of Pusey’s criticism. The MS. has three parts, each written in a different hand, the first and most important part being the supposed _Tractatus de Causis et Indiciis Morborum_, which covers folios 2-87. The second part is a fragment of some as yet unidentified medical work (folios 88-115); and the third, consisting of the first and last folios, gives us an introduction and an end piece to the first part.

The alleged author and translator are named on the first page:

هذا كتاب موسى ابن ميمون الفه
للعموم قاطبا وقد نقله التميمي
الشيخ سليمان الحبشى المكنا بابن حبيش
في مملكة القدس الشريغة
تم

‘This is the book of Mûsa ibn Maimûn which he put together as a
compilation for general use. Al Tamimi, the sheikh Sulaiman the
Abyssinian, known as Ibn Ḥubaish,[375] translated it in the noble
city of Jerusalem. Finis.’

On the next page there is an introduction to the book which commences:

بسم الله الرحمان الرحيم
قال موسى ابن ميمون القرطبى الاسرايلي الخ

‘In the name of God, the Merciful, the Compassionate.
So says Mûsa ibn Maimûn, the Cordovan, the Israelite,’ &c.

The whole of the passage is an extract from chapter vi of the Aphorisms of Maimonides, adapted as a kind of introduction, and runs as follows:

قد علمت في قولي هذا في قوة النفسيه والقوة الحيوانيه والقوة
الطبيعيه ولنسم الان في هذا الاصطلاح جميع افعال البدنيه
للانسان قول ان اشرف الافعال التنفس وبعده النبط والاحساس
واشرف الاحواس البصر ثم السمع وبعده الاحساس شهوة الطعام
والشراب وبعد ذلك الكلام وبعد ذلك التمييز اعني الذي بها التفل(_sic_)
والفكر وبعد ذلك الحلافه لساير الاعضاء علي المعتادة وهذه الرتبة
في شرف انما هي بحسب ضرورية الحيوة او صالحية فتعلم ان
الطبيعة اسم مشترك يقال علي معنى كثيرة كالقوة المدبرة (_sic_)الحيوان
ايضا طبيعية وما هو اشرف وتمسكت للاشرف في الاشراف وهذه
الاسباب الذي قد رايناها ورتبناها وهو الابتداء في النزلات الزكاميه
من الراس

_Trans._ ‘I teach in this discourse of mine concerning the animal
power, the vital power, and the natural power, but we will here
call all man’s bodily functions by one name. There is a saying that
the noblest of the functions is breathing, next the pulse, and
lastly the senses. Of the senses, the noblest is sight, which is
followed by hearing. Following on the senses is the appetite for
food and drink, after it being speech and then the mind; I mean
that which contains the reason and the intellect. Next comes the
[?] allocation of [the various powers to] the other parts of the
body according to the customary manner. This arrangement in order
of nobility is only according to the requirements of life or [?]
health.

‘You will recognize that “nature” is an equivocal term which can
be used in many meanings. [One of these meanings,] for example, is
“the motive power of animals”. So, too, is “natural”.

[??...] ‘and that which is nobler. And you will retain the noblest
of the noble [functions]. And these causes which we have noticed
we have set down in their order; and the beginning is concerning
catarrhal discharges from the head.’

Compare with this the real text of Maimonides:[376]

קד עלמת קול אלאטבא קוי׳ נפסאניה וקוי׳ חיואניה וקוי׳ טביעיה.
ולנפס אנא אלאן פי הדה אלאצטלאח גמיע אפעאל בדן אלאנסאן אלאפעאל
אלבדניה [ואשרף אלאפעאל אלתנפש ובעדה אלנבט[377]] ובעדה אל אחסאס.
ואשרף אלחואס אלבצר. תם אלסמע ובעד אלאחסאס שהוה אלטעאם
ואלשראב. ובעד דאלך אלכלאם. ובעד דאלך אלתמייז. אעני בה אלתכייל
ואלפכר ובעד דאלך חדכה סאיר אלאעצא עלי מעתאדהא והדה אלרטבה(sic)[378]
פי אלשרף אנמא הי בחסב צרוריה אלחיאה או צלאחיה אסתמראהא״
ובעד הדה אלמקדמה פלתעלם אן אלטביעה אסם משתרך יקאל עלי
מעאני כתירת ומן גמלה תלך אלמעאני אלקוה אלמדברה לבדן אלחיואן
פאנהא אלאטבא יסמונהא איצי טביעה והדב אלקוה הי איצי . . . . . .
פאן גלבת ען דלך בדלת מא הוא אשרף ותמסכת באלשרף פאלאשרף
.ובחסב הדה אלתרתיב יעלם אלמרץ אלח׳

‘Thou knowest the opinion of the physicians [concerning] animal
power, vital power, and natural power. But it is my intention
here to call all the functions of man’s body by the one name of
“bodily functions”. [The noblest of the functions is breathing,
next the pulse,[377]] and lastly the senses. Of the senses, the
noblest is sight, which is followed by hearing. Following on the
senses is the appetite for food and drink, after it being speech
and then the mind, by which I mean the thoughts and the intellect.
Next comes the motion of the other parts of the body according to
their customary manner. This arrangement in order of nobility is
only according to the requirements of life or the health of its
faculties.

‘From this preface you will recognize that “nature” is an equivocal
term which can be used in many meanings. One of these meanings [for
example] is “the motive power in the bodies of animals” which the
physicians call “nature” too.... And if you discover this, you will
exchange that which is nobler and retain that which is noblest. By
means of this process of arrangement, a disease can be recognized,’
&c.

This introduction was added when the folios stood in a state of disorder different from their present one. The catchword at the bottom of the page [وهذا = and this] points forward to the title already mentioned,[379] which appears on folio thirty-nine of the present arrangement. The text below this title is part of the chapter on discharges and catarrh, so that the folio once followed immediately on the introduction, being then, too, out of its proper place.

The last page, written in the same hand as the introduction, bears a piece of some unidentified work and a colophon which reads:

وقد تم هذا الكتاب الشريف تاليف موسى ابن ميمون القرطبى
الاسرايلى رحمه الله مما الف وجرب هذا الكتاب المبارك وعدد فصوله
امراض البدن مما رتبه على اوضاعه (_sic_)مائة وست فصول للجميع
سبع مالة وخمسة وستين (_sic_)٦٥٢٧ تم الكتاب فى سنة

‘This noble book is finished; the composition of Mûsa ibn Maimûn
the Cordovan, the Israelite, to whom God be gracious. This blessed
book is part of that which he composed and tested. The number of
its chapters is 106, dealing with all the diseases of the body,
which he arranged in their proper order.

‘The book was completed in the year 765.’[380]

The number 106, which according to the colophon is the number of chapters in the book, is really the number of titles in the MS. written in large hand. Fragments of many chapters whose titles are lost still remain in it however, while many of the chapters that have preserved their titles are no longer complete.

Again it may be pointed out that all the known medical works of Maimonides were written in Arabic and therefore did not need to be translated into that language as the Bodleian MS. claims to have been. The spurious title-page thus further betrays itself by saying that this work was translated from _Hebrew_.

Finally, the identification of the real contents of the Paris MS. disposes of the last foundation of the idea that Maimonides wrote any compendium of medicine known as كتاب الاسباب والعلامات (_Tractatus de Causis et Indiciis Morborum_), and clears up the confusion caused by the faulty entries in the Paris and Bodleian catalogues.

SCIENTIFIC DISCOVERY AND LOGICAL PROOF

By F. C. S. Schiller

§ 1. Among the obstacles to scientific progress a high place must certainly be assigned to the analysis of scientific procedure which Logic has provided. This analysis has not only been inadequate in itself, but has set itself a mistaken aim. It has not tried to describe the methods by which the sciences have actually advanced, and to extract from their experience the logical rules which might be used to regulate scientific progress, but has treated scientific discoveries almost entirely as illustrations of a preconceived ideal of proof, and so has freely rearranged the actual procedure in accordance with its prejudices. For the order of discovery there has been substituted an order of ‘proof’, and this substitution has been justified by the assumption that if discovery had taken the ideally best course, it would have coincided with the process of proof. It followed, of course, that the same logic would do for both, and that this logic was already in existence.

The damage thus inflicted upon Science was twofold. Not only were the logicians given a plausible excuse for persisting in their profound misapprehension of scientific inquiry and rendered incapable of giving any help or guidance in the solution of actual problems, but, what was much worse, the scientists themselves were misled about the nature of their operations.

The precise value of the service which a correct logical analysis of its procedure might have rendered to Science is perhaps open to dispute, though it must surely be beneficial to operate consciously, and with a full understanding of their nature, the methods which have been hit upon empirically; but even if logicians have commonly been too unfamiliar with the details of scientific problems to offer much practical advice, it would be difficult to overrate the mischiefs which must have resulted from referring scientists to an incorrect analysis of their actual procedures. For the attempt to justify by such a false ideal what they had actually done was bound to divert their attention from the methods that were actually effective and fruitful to others which were impracticable and sterile, to waste energy upon false aims and impossible ideals, and so to hamper scientists fatally in the exercise of their scientific rights and powers.

Hence it is not too much to say that the more deference men of science have paid to Logic, the worse it has been for the scientific value of their reasoning, while the less they have troubled to know about the theory of Science, the better it has been for their practice.

Fortunately for the world, however, the great men of science have usually been kept in salutary ignorance of the logical tradition and left to their own devices, by the accident that the historical organization of academic studies nearly everywhere confined ‘logic’ to the literary curriculum. Nevertheless, the moral of this situation is not that it is right for science to neglect logic and for logic to despise science, but that science should appeal from logic as it is to logic as it ought to be, and should insist on being provided with a _reformed_ logic. For surely if a scientific education is to be more than a narrow and technical specialty, and is to exert a ‘liberalizing’ and broadening effect on the mind, it _ought_ to include a study of scientific method in its generality and a certain understanding of the intellectual instruments by which all others are operated and constructed.

The whole evidence for these contentions it will not, of course, be possible to marshal within the limits of this essay, but the systematic criticism to which the whole traditional logic has been subjected in my _Formal Logic_[381] may perhaps absolve me from the duty of substantiating them exhaustively. It may suffice to indicate the extent of the scientific grievance against ‘logic’ by drawing up a list of problems in the logic of science which the traditional logic has misconceived, and then to select for fuller treatment a palmary example of the radical discrepancy between the two.

The traditional logic may be convicted of having gravely misrepresented, (1) the value of classification and the formation of classes, scientific processes of which the real logic was only revealed by the Darwinian theory, (2) the function of definition, (3) the importance of analogy, (4) of hypothesis and (5) of fictions, (6) the incomplete dependence of scientific results on the ‘principles’ by which they are (apparently) obtained, (7) the formation of scientific ‘law’ and its relation to its ‘cases’, (8) the nature of causal analysis. Other important features of scientific procedure cannot be said to have been recognized at all, e.g. (9) the problem of determining what is _relevant_ to an inquiry and what practically must be, and safely may be, excluded, (10) the methods and justification of _selection_, (11) the essentially _experimental_ nature of all thought and consequent inevitableness of _risk_, (12) the necessity of so conceiving ‘truth’ and ‘error’ that it is possible to _discriminate_ between them, and (13) the need for an inquiry into _meaning_ and into the conditions of its communication.

I

§ 2. The most instructive, however, of the discrepancies between ‘logic’ and scientific procedure will appear if we compare the logical notion of _proof_ with the scientific process of _discovery_, and examine how far it can afford any means of regulating, stimulating, or even apprehending the latter. We shall find that the logical theory of ‘proof’ has no bearing on the scientific process of discovery, is not related to what the sciences call proof, and can only have a paralysing influence on any scientific activities which try to model themselves upon it. On the other hand, the study of the process of discovery will point to an important correction in the notion of logic.

§ 3. The scientific uselessness of the traditional logic should not, however, excite surprise. For what reason was there to expect that the theory of proof should turn out to be adequate, or even relevant, to scientific procedure? It had sprung from a totally different interest, proceeded on different assumptions, and aimed at different ends. It did not spring from interest in the exploration of nature, and did not aim at its prediction and control. Nor did it presuppose an incomplete system of knowledge which it was desired to extend and improve. It originated in a very special context, from the social need of regulating the practice of dialectical debate in the Greek schools, assemblies, and law-courts. It was necessary to draw up rules for determining which side had won, and which of the points that had been scored were good.

These were the aims Greek logic set itself, and successfully achieved. But the impress of this origin remains stamped all over it, and the accounts given of logical proof ever since have retained essential features of Greek dialectics.

Thus it was assumed that science could start from principles, as indisputable as are the current meanings of words in a dialectical debate, and the end of the whole theory of proof was always conceived as being to secure the conviction (ἔλεγχος) of one party to a dispute, who was to be definitely crushed by the triumphant cogency of a syllogistic demonstration, while the more real and fruitful analogy between scientific inquiry and debate, viz. that _there is always another side_, to which also it is well to listen, was unfortunately obscured by Aristotle’s discovery of the syllogistic form and its show of conclusiveness. But for the purpose of apprehending scientific procedure the syllogism is a snare: by putting scientific reasoning into syllogisms, the difference between the true and the false views is made to appear qualitative and absolute, instead of being a quantitative question of more or less of scientific value. Thus dogmatism is fostered at the expense of progressiveness, and the mistake is committed of approaching the discovery of truth in a party spirit. Hence its dialectical origin has become _fons et origo malorum_ for logic.

§ 4. It is true that this mistake is very old, and has grown deeply into the fabric of logic. For Aristotle had no sooner worked out the classic formulation of the rules of dialectical proof than he proceeded to extend their scope by applying them to the theory of science, in the _Posterior Analytics_. His instinct in so doing was sound enough; for there is no better verification of a theory than its capacity to bear extension to analogous cases. And of course if this extension had been successful, it would have supported the belief that the theory of discovery could profitably be amalgamated with that of proof.

Unfortunately, however, the verification only seemed to be successful. Aristotle chose to exemplify his theory of scientific proof from the mathematical sciences. His choice was natural enough, because they were the only sciences which had reached any considerable development in his day, and they had, moreover, an apparent necessity and universality and a fascinating appearance of exactness. But he had unwittingly chosen the most difficult and deceptive exemplification of scientific procedure. Because the mathematical sciences were in a relatively advanced condition they seemed to lend themselves to his design. He could there find terms whose meaning, and principles whose truth, was no longer in dispute. They could in consequence be argued from with as much assurance as debaters could assume the recognized meanings of words. And the fact that results seemed to follow from mathematical definitions and premisses which were not merely verbal, shed a delusive glory on the forms of dialectical proof by which they had been reached. Hence it easily escaped notice that the logical superiority of mathematics was an achievement, not a datum. Just because the mathematical sciences were very ancient, their origins had been forgotten, and with them the tentative gropings which had first selected, and subsequently confirmed, their principles. They had become immediately certain and ‘self-evident’, and no one was disposed to dispute them. On this psychological fact the whole theory of logical proof was erected.

Again, it was natural to suppose that the true nature of scientific knowing must be revealed in its most perfect specimens: no one stopped to reflect that even so the real difficulties of making a science are more keenly felt and more easily seen in the nascent stage than in one which has victoriously overcome them, and has rewritten its history in the assurance of its prosperous issue.

Lastly, the subtle ambiguity which pervades all mathematical reasoning, according as its terms are taken as _pure_ or as applied, was overlooked entirely--with the disastrous result that the universality, certainty, and exactness pertaining (hypothetically) to the ideal creations of ‘pure’ mathematics were erroneously transferred to their ‘applied’ counterparts. To this day logicians are found to argue that real space is homogeneous because it is convenient in Euclidean geometry to abstract from the multitudinous deformations to which bodies moving through it are subjected, and to leave them to be treated by physics;[382] nor are they aware of any lack of ‘exactness’ and discrimination when they identify the ideal triangle with the figures they draw on the blackboard.

§ 5. After its apparent success in analysing mathematical procedure there was no more disputing the supremacy of the theory of ‘proof’. The facts that its field of application was soon found to be much narrower than that of science, and that it failed egregiously to apply to the procedures of the (openly) empirical sciences, and _a fortiori_ could not justify them, if they were noticed at all, were held merely to show that these sciences stood on a low level of thought, which from the loftier standpoint of logic could be contemplated only with contempt; if they required help and got none, so much the worse for them. Accordingly the whole theory of science was so interpreted, and the whole of logic was so constructed, as to lead up to the ideal of demonstrative science, which in its turn rested on a false analogy which assimilated it to the dialectics of ‘proof’. Does not this mistake go far to account for the neglect of experience and the unprogressiveness of science for nearly 2,000 years after Aristotle?

§ 6. Yet the deplorable consequences of this error should not render us unjust. The influence of Aristotelian logic on the theory of science was natural, and in a sense deserved. For Aristotelian logic is perhaps the mightiest discovery any man has achieved single-handed. Its might is sufficiently attested by the length of its reign. Euclidean geometry alone is comparable with it, and Euclid owed far more to his predecessors than Aristotle. Moreover, the Aristotelian logic may be said to have achieved its purpose. It was able to regulate dialectical discussion. The syllogism did determine whether a disputant had proved his case, and for any one who had accepted its assumptions its decision was final, while even its severest critics had to admit that it was an indisputable fact, the interpretation of which was a real problem.

Unfortunately, there is not yet any agreement among logicians about the solution of this problem. Aristotle’s own analysis did not go back far enough: he stopped short at the _Dictum de Omni_ and the reduction of syllogisms in the second and third figures to the first. He did not penetrate to the ultimate assumptions which were implied in the dialectical purpose and social function of the syllogism. But the truth is that syllogistic reasoning presupposes quite a number of conventions which Aristotle did not state, and which can hardly be said to have been adequately recognized since.

§ 7. (1) The first of these may be called the _Fixity of Terms_. Syllogistic reasoning manifestly depends on the assumption that the terms occurring in it have meanings sufficiently stable to stand transplantation from one context to another; for only so can they establish connexions between one context and another. Thus a syllogism in _Barbara_ argues that because _all M is P_ and _all S is M, all S must be P_. But it can do this ‘validly’ only if _M_, its middle term, remains immutably itself, and is the same in both premisses. Doubt, dispute, or confute this assumption, and the cogency of the syllogism as a form of ‘proof’ is overthrown at once. If the sense in which _M is P_ is not the same as that in which _S is M_, the syllogism breaks in two, and its conclusion becomes precarious. Raise the question of how far reality conforms to this assumption, and you get at once a subtle problem of the applicability of the syllogistic form to the case in hand, which is precisely analogous to the question whether a theorem of pure mathematics is applicable to the behaviour of a real thing. In either case the cogency of the ‘proof’ which establishes the conclusion is impaired and ceases to be unconditional. The conclusion of a ‘valid’ syllogism will only follow _if_ the middle term can be known to be unambiguous, and if the objects designated by the terms do not change rapidly enough to defeat the inference. And that this is the case can usually be ascertained only by actual experience. The conclusion, therefore, cannot be simply deduced; it has actually to _come true_, before we can be sure that the reasoning _was_ sound. Absolutely _a priori_ proof thus becomes impossible, if the assumption of the fixity of terms is contested: all proof becomes, in a sense, empirical.

Nevertheless, experience shows that the fixity of terms, though not a ‘fact’, is _a valid ‘fiction’_: in ordinary discussion the terms may usually be taken as fixed enough to render valid syllogisms common. An ordinary debate proceeds upon the assumption that the meaning of the terms involved is fixed, and cannot be varied arbitrarily. To science, however, this assumption does not apply without restriction. In a progressive science the meaning of terms often develops so rapidly that such verbal reasoning does _not_ suffice. Hence the mere occurrence of verbal contradictions in a scientific reasoning is no proof that the argument is unsound. It may show merely that its terms are _growing_.

It should be observed further that this same assumption is implied in the fundamental ‘laws of thought’ on which the traditional logic rests. Indeed, the notorious ‘Law of Identity’ seems to be merely another statement of it. It is usually formulated as ‘_A is A_’, but in its actual logical use it is really the assumption that ‘everything _is_ what it is called’. It is, of course, anything but self-evident that ‘_A_’ _is A_, but _unless_ the _S_, _M_, and _P_ of the syllogism are _rightly_ so called, the syllogism will not hold. Similarly, the Law of Contradiction collapses at once if the terms to which it is applied are allowed to change. The inability of ‘_A_’ both to be _B_ and not to be _B_ vanishes if ‘_A_’ is not fixed and may change its habits. And of course the real things known to science all change, and are fixed only by a fiction. Hence every application of the logical convention to real things may be challenged: it involves a fiction and takes a risk, and both of these may be bad. But the traditional logic ignores both the risk and the fiction and the lack of cogency in its attitude.

§ 8. (2) It is a further presupposition of the syllogism that the meaning of its terms is _known_. When a discussion is begun the parties to it are supposed to understand each other, and not to have first to find out and form the meaning of the terms they use. This assumption also is roughly true in ordinary debate, and its convenience is manifest. If things are rightly named, and if this feat has been accomplished once for all--presumably by Adam and Eve before they were turned out of Paradise for trying to know too much--we shall escape many of the most trying difficulties of scientific inquiry. We need no longer trouble whether the best names have been given, and whether a name good for one purpose is equally good for another, nor need we inquire whether our names may not unite what is alien on account of a superficial likeness, or separate what is akin on account of a superficial difference.

In science, on the other hand, the assumption that we know what meanings our terms can convey is not made as a matter of course. We may begin with roughly labelling objects of interest, and then inquiries may be conducted into, e.g., ‘electricity’, ‘elements’, ‘life’, ‘species’, &c., in the hope of settling what these terms _shall_ mean, and of finding out _more_ about their meaning, and without making the assumption that whatever new facts are discovered about them must conform to our preconceptions and confirm our nomenclature. Thus to a man of science it will not be cogent to argue that because an ‘element’ is (by definition) an ultimate form of matter which cannot be broken up, and ‘radium’ breaks up, ‘radium’ is not an ‘element’, or that because ‘species’ are eternal forms, and the Darwinian theory claims that they are not immutable, it can be dismissed as involving the ‘contradiction’ that a ‘species’ is not a species. Thus the best syllogisms lose their cogency so soon as a question is raised whether the verbal identity of their terms is an adequate guarantee of the real identity of the things they are applied to.

§ 9. (3) It is a further presupposition of the logician’s conception of ‘proof’ that absolute truths exist, and that in the ideal demonstration they form the premisses from which the conclusion follows. This presupposition is not stated, and is not implied in the form of the syllogism. For a syllogism is no less ‘valid’ if its premisses are true only hypothetically, and not absolutely. Indeed, it is not thought to impair the ‘validity’ of a syllogism that its premisses should be utterly false. At any rate we can _reason_ quite as well with hypotheses and probabilities as with absolute truths, and this is in fact what we usually do, whether or not we are aware that our premisses are conditional and hypothetical. This ordinary practice, however, is resented by the traditional logic. For if our premisses are only hypothetically true, how can they lead to conclusions which can be declared absolutely true? And if our conclusions are not absolutely true, how can they be certain? Are they not bound to remain infected with the doubts which beset their premisses?[383] As we value the certainty of our conclusions, therefore, absolutely true and certain premisses must be procured. If they cannot be procured, even the best formal proofs will remain hypothetical, and all truth will become dependent on experience. For if nothing is true absolutely, and every truth has originated humbly in a guess that has grown into a successful hypothesis, it can always be suggested that after all it may benefit by a little more verification. It may be true enough psychologically and for practical purposes, but it does not realize the ideal of ‘logical certainty’.

§ 10. This ideal Logic has formulated from the first. Aristotle already was not content with merely analysing the form of reasoning; he aspired to formulate the norm of scientific demonstration. The ‘demonstrative syllogism’, which he held to be the form of truly scientific reasoning, differs from the formal syllogism in two essential respects. Its premisses are absolutely true, and its middle term states the real ‘cause’, which connects its terms and is not merely a _ratio cognoscendi_. The reasoning proceeds, therefore, from premisses which are unambiguous, true, and certain, i.e. _necessarily_ true and _absolutely_ certain. Nor does the conclusion lose any of this excellence. Logic puts on a fine air of modesty, and merely claims that the syllogistic form is a guarantee that no truth can be _lost_ on the way from the premisses to the conclusion in a ‘valid’ argument. If, therefore, our thought is properly arranged, our conclusion will be as true and certain as were its premisses, and no man will be able to gainsay it. It is the great beauty and merit of the syllogistic form that it is an arrangement which gives us this guarantee.

It was natural, therefore, that throughout the history of logic enormous importance should be attached to the acquisition of unquestionable starting-points. For the possession of ‘valid forms’ was not enough. It only insured against loss of truth, it did not provide for its acquisition. It seemed, however, to imply that truth could only be generated out of truth, and handed down from the premisses to the conclusion. Hence the insistent demand for assured starting-points, self-evident ‘principles’, which the infallible method of syllogistic deduction might conduct to equally certain conclusions.

In reality, however, this demand for certainty was extra-logical: it is not required for the purpose of analysing reasoning. For it is just as easy to reason from doubtful and probable premisses as from certainties, nor need the doubt in the reasoner’s mind affect the form of the reasoning. If, however, there is an imperative desire for certainty, it must be somehow gratified by logic. And there seemed to be no way of doing so except by ascribing absolute truth and certainty to the initial principles of science.

Of course it was covertly assumed that certainty could only be reached by _starting_ from certainty, and that no possibility of a growth of assurance in the progress of the reasoning could be entertained. In a sense this assumption was correct (cf. §§ 27, 28), because it is true that the gradual verification of scientific truths does not render them absolute; but it led to neglect of all methods which appeared to start with premisses initially doubtful and hardening into certainties by gradual confirmation. No doubt it was not strictly impossible to reason from premisses not known to be true, but such reasoning was despised as ‘dialectical’, and no inquiry was made into the frequency of its occurrence in actual science. Why, then, waste time upon so unworthy a procedure, instead of fixing one’s whole attention upon the truly logical ideal, the absolute proof of absolute truth? Let us maintain, rather, the old Aristotelian[384] conviction that the truly scientific syllogism proceeds from premisses that are true and underivative (because ‘self-evident’) and inerrant, and demonstrates its conclusion with ineluctable necessity! Thus the attainment of _absolute truth_ was unobtrusively smuggled in as the aim of reasoning, and became an integral feature of the ideal of ‘demonstration’.

§ 11. From the standpoint of the scientific inquirer, however, this whole theory of proof is open to the gravest objections. He finds first that it is impracticable, being composed throughout of counsels of perfection with which he cannot comply, and then that, even if he could, they would be perfectly useless, and destructive of his aims.

(1) It strikes him at once that the Fixity of Terms is an obvious _fiction_. He will of course be aware, from his scientific experience, that fictions have their uses and are often indispensable; but he will know also that not all fictions are useful, and that the adoption of a fiction has in each case to be justified by its usefulness. Moreover, it is not so much its immediate and prospective use which justifies it, though this yields the usual motive for its adoption, as the ulterior uses ascertained _ex post facto_ by experience.

He will ask, therefore, for evidence that an _absolute_ fixity of terms is the vital necessity for logic it is declared to be. He will admit, of course, the familiar arguments for a certain _stability_ of meanings which have come down from the days of Plato, but he will suggest that a _relative_ fixity of terms is quite sufficient to content them. He will point out that in a progressive science any absolute fixity in its terms is precluded by the very progress of the science. For the terms in use must somehow manage to convey the _growing_ knowledge they are employed to ‘fix’. The term ‘gas’, for example, must not be tied down to the meaning Van Helmont desired to convey when he invented it; it must incorporate all that physics has discovered about ‘gases’ ever since. Similarly, when Darwinism transforms the notion of ‘species’, and the discovery of radio-activity that of ‘atom’, these developments of meaning must be recognized as perfectly proper. To object to these conceptions as modern science uses them, on the ground that, because to Plato and Aristotle species were eternal and immutable, a ‘species’ that changes cannot be truly a species, or that because an ‘atom’ is etymologically ‘indivisible’, it becomes an impossible self-contradiction when it is made up out of ‘electrons’, will seem to him to reveal only the fatuous pedantry of an utterly unscientific mind.