Wheat from Chaff – Hime’s ‘gunpowder cipher’

Header picture: Mongols using grenades/bombs in 13thC Japan.

preceding posts:

Wheat from the Chaff – ‘Bacon ciphertext
Wheat from Chaff – Books of Secrets and the ‘Secretum secretorum

The “gunpowder recipe”  in Bacon’s  De secretis ..

The essential reference is:

  • H. W. L. Hime (Col.), “Roger Bacon and Gunpowder,” in Roger Bacon: Commemoration Essays, ed. by A. G. Little (Clarendon Press, Oxford, 1914) pp.321-335.

In 2002, while discussing the range of early cipher methods, Pelling transcribed the passage and explained Hime’s rendering of it:

an anagrammatic cipher [which] supposedly transforms… ” luru vopo vir can utriet” into R. VII PART. V NOV. CORUL. V ET … which is allegedly short for…“recipe VII partes, V novellae coruli, V et..”   …the central part of his [i.e. Bacon’s] recipe for gunpowder.

To include mention of that passage from De Secretis in a more specifically ‘Voynich-‘ context would be to accept that some connection exists between Roger Bacon and the Voynich manuscript, and while some form of connection might exist, none has yet been argued from the primary evidence so the ‘gunpowder’ passage from De secretis should be irrelevant, shouldn’t it?

Reeds realised this,  and apparently  so too  did Robert Steele. Reeds’  Voynich Bibliography  includes none of  Hime’s essays and to the listing for Steele’s article (below), it adds a note:  “..about Bacon ‘gunpowder cipher’,  not VMS“.

  • Robert Steele, “Luru Vopo Vir Can Utriet.” Nature 121 (11 Feb. 1928), pp.208-9. The article’s abstract (which is all I’ve seen) mentions another item (NATURE, Sept. 4, 1926, p. 352).

Unfortunately, these are among the few since 1914 to recognise that distinction, the majority distracted first by Hime’s supposing  the passage in De secretis.. proved Bacon invented gunpowder.

A false connection

Combined with Wilfrid’s (also unproven) assertions that the Voynich text was written by Bacon and is in cipher, the topic of de Secretis’   ‘gunpowder cipher’ is included again and again in Voynich-related articles, books and theories to as late the present (2018), when mention is made of it in Dooley’s book:

  • John F. Dooley, History of Cryptography and Cryptanalysis: Codes, Ciphers, and Their Algorithms. (2018).

Dooley’s chosen sources are curious, but the second plainly implies supposing some link to Beinecke MS 408.

     #Brian Clegg, The First Scientist: A Life of Roger Bacon (2003).

     #Lawrence Goldstone & Nancy Goldstone, The Friar and the Cipher: Roger Bacon and the Unsolved Mystery of the Most Unusual Manuscript in the World (2005).

Essentially a biography which turned into a Voynich-themed historical novel, the Goldstones’ book offers no new insight into the imagery, text or manufacture of Beinecke MS  408. see Review by Kirkusthe final line of which is “Many scrambled historical eggs conceal the Bacon.” and The New York Times comment begins:

“When two Westport authors, Lawrence and Nancy Goldstone, decided to write a history of the 13th-century scientist Roger Bacon, they had no idea the trail would lead them to one of the world’s great mysteries. But when they discovered that the brilliant but reviled man of science might have hidden information in a strangely coded manuscript now at Yale University, that became the theme of their new book … ” NYT (Feb 20, 2005).

Seeing how this particular irrelevancy  survived will shed light on the way that other ideas long doubted, or modified, or weeded out entirely from reputable scholarship are still part of the ‘Voynichworld’ landscape.

It was a hundred and three years ago – and before Wilfrid’s talk to the Physicians of Philadelphia –  that Lynn Thorndike explained why the ‘gunpowder cipher’ is likely to be a late addition to Bacon’s original text Writing in 1915,  just a year after Hime’s essay appeared in print, Thorndike wrote:

Lynn Thorndike

“In the first place, the cipher [as asserted by Hime] is based upon chapters of the “Epistola de secretis operibus naturae et de nullitate magie” not found in the early manuscript of that work and considered doubtful by Charles* in his work on Roger Bacon. Indeed, the opening phrases of two chapters, ” Transactis annis Arabum sexcentis et duobus,” and ” Annis Arabum 630 transactis” suggest their source. Secondly. Roger Bacon openly alludes to gunpowder in 1267 in his ” Opus Tertium ” as already in common use in children’s toy explosives. Therefore Colonel Hime has to date the “De secretis” at 1248, and to hold that Bacon was at that time “driven to employ cryptic methods by fear of the Inquisition” (p. 334), but that by 1267

“circumstances had totally changed in the lapse of years; the composition of gunpowder . . . had been divulged, and the first use made of the deadly mixture was for the amusement of children” (p. 321).

But is there any good reason for dating the “De secretis” in 1248? Much of it sounds like a brief popular compilation from Bacon’s three works of 1267-8 concocted by some one else later; compare, for instance, the first paragraph of the sixth chapter of the “De secretis” with Duhem, “Un fragment inedit de l’Opus Tertium,” pp. 153-4 and Little, “Part of the Opus Tertium,” 50-51. The dedication of the “De secretis” to William, Bishop of Paris, who died in 1249, occurs first in the late edition of 1618 and has not been found by Little in any manuscript. Then the inquisition bug-a-boo is negligible. Has any one ever shown that the inquisition punished a practical invention? … it can not be shown that in the thirteenth century the church persecuted men of science. Rather, popes and prelates were their patrons.”

quoted passage above from:

  • Lynn Thorndike, ‘Bacon and Gunpowder‘, Science, New Series, Vol. 42, No. 1092 (Dec. 3, 1915), pp. 799-800. (p.799).

* ‘Charles…’ is presumably E. Charles, author of Roger Bacon: sa Vie, ses Ouvrages, ses Doctrines (Bordeaux, 1861) to whom Thorndike refers several times, not always approvingly.

For current opinion on authorship and dating for De secretis see:

  • Jeremiah Hackett, (ed.)  Roger Bacon and the Sciences: Commemorative Essays 1996 (Brill)

Thorndike’s protest had little effect and for the next half-century, the idea continued to circulate in European popular histories that the invention of gunpowder should be credited to a thirteenth-century Anglo-Norman friar.  What is notable about these writings is an apparent inability to contemplate Europe’s being in debt to Asian, or even Arabic-speaking peoples. Sarton would be among the few exceptions and yet, despite Sarton’s discussion (in 1931),  Lutz  asserts (in 1936) any Oriental or Arabian origin ‘disproved'(!!). (Cf. header picture and illustration below, right).

Meanwhile, Six years after Thorndike’s first protest,  he had again (1921) objected to the constant repetition of the idea that Bacon invented gunpowder, in a letter to  Scientific American which I’ve already reproduced in part.

No noticeable diminution in the idea’s popularity followed, and then

20 years later (1936) , a paper by Edward Lutz again repeats as if they were facts established that  Roger Bacon wrote the Voynich manuscript, and invented the telescope,  the microscope… and gunpowder.

Friar Bacon and hypothetical telescope. From Lutz (1936)

Of gunpowder, Lutz wrote:

“Invention of Gunpowder: In this connection a few words about the invention of gunpowder seem to be in place. If nothing else, Friar Roger was the first European to make mention of gunpowder.[a]  Since its Chinese and Arabian origin has been disproved, we may add that good arguments exist for its actual invention or chance discovery by Bacon during his long life of research. He wrote about gunpowder’s main characteristics before anyone else [sic!] had even mentioned the substance. He possessed its exact chemical formula and hid it within a subtle cipher.[b]

[a] citing, (as n.244)  – W. W. R. Ball, History of Mathematics (1919), p. 174.  [b] citing  (as n.225)  W. R. Newbold,  Cipher of Roger Bacon, pp. 141-143; and Hime’s article  “Gunpowder” published in the Encyclopaedia Britannia (1929). Vol. 2  p. 890.

  • Edward Lutz, ‘Roger Bacon’s Contribution to Knowledge’, Franciscan Studies, No. 17, June, 1936), pp. ii-v, vii-xi, 1-82.

And , dear reader, if you’re thinking  Lutz  was an outlier  –   think again.

Thirty-five years after Thorndike’s critique, now (in 1950) a young Hochberg attempts to judge the matter without doing more than exercising logic on a prohibitively narrow range of data, and all at the level of secondary opinion. The result is erroneous conclusion.

detail from the ‘Mara Buddha’ –  foreign ‘demons’ attack Dunhuang’s Buddhist enclaves. (10thC AD). One fire-propelling item is understood to be a grenade and the other a fire-lance.

A further controversial question concerning [Roger] Bacon’s achievements is whether or not he discovered gunpowder. … Colonel Hime, in perhaps the most authoritative work on the question of Bacon and his relation to the discovery of gunpowder, concludes that Bacon, in the face of the evidence, must be considered to be the discoverer of gunpowder … While it is true that Hime’s conclusion depends upon a certain amount of hypothesizing and conjecture … the conclusion is far from being unreasonable. Nevertheless, both Thorndike and Sarton have challenged the theory that Bacon discovered gunpowder. Their attack centers on Hime’s proposed decipherment of the De Secretis (15, pp. 688- 691; 12, pp. 957-958, 1037-1038). Sarton, however, seems to admit that the issue is not decisive…

  • from Herbert Hochberg, ‘The Empirical Philosophy of Roger and Francis Bacon’. Philosophy of Science, Vol. 20, No. 4 (Oct., 1953), pp. 313-326.

The aim in referring to Hochberg’s essay from so long ago is not to criticise Professor Hochberg for youthful errors;  but to make clear that an exercise of logic cannot make up for a failure to determine the facts by research –  and further that to rely on no more than a limited sample-range – especially of secondary opinion – is to beg the questions they left unasked.  In this instance, the critical question was  not, as Hochberg supposed (more than half a century ago), “which of these secondary authors’ ideas do I think most plausible?” but ‘Where and when do we find our earliest testimony to the existence of gunpowder?”


Sixty-three years later, (in 1978) d’Imperio’s Elegant Enigma – whose subject is the Voynich manuscript – includes three of Hime’s essays in its bibliography,  though d’Imperio herself adopts a non-committal tone in the main text:

A considerable literature exists, dealing with ciphers attributed to Bacon in alchemical works.  An anagram in which Bacon is said to have hidden a formula for gunpowder [in de secretis] is explicated variously by some but debunked by others. [the sources are cited – Elegant Enigma, pp.66-67).

Note that d’Imperio does not ignore, but fails to credit to its source, Thorndike’s opinion that the cipher-passage is a later interpolation to De secretis, and also fails to see that the entire question is irrelevant to study of Beinecke MS 408, given lack of any positive evidence for correspondence between Bacon’s extant works and the Voynich manuscript.

Who did invent gunpowder? 

The question was settled beyond all reasonable doubt by Joseph Needham, whose 700-page study was published fully thirty years ago.

Yet …

One hundred and two years after Thorndike’s protest, and thirty-one years after Needham’s exhaustive study,  when Craig Bauer (rightly) asserts (2017) that Hime’s decipherment of the passage in De secretis remains in dispute – his footnote includes not only Hime’s publications about the passage from De secretis but also that Voynich-themed biography of Roger Bacon later referenced by Dooley!  What uncertainty exists is not, today, where gunpowder was first invented but only about which European friar ( Friar Roger or Friar Berthold) first knew its method for manufacture.   And that dispute has no demonstrable link to the Voynich manuscript, at all.

  • Craig P. Bauer, Unsolved!: The History and Mystery of the World’s Greatest Ciphers from Ancient Egypt to Online Secret Societies (2017), p.23 (and notes p.532).

re: Friar Berthold – the legend persisted to 1911.  See the linked entry which cites

  • Hansjacob, Der Schwarze Berthold, Der Erfinder des Schiespulvers u. der Feuerwaffen (Freiburg, 1891).


from Needham, op.cit., (p.51).

[following paragraph added Jan 4th., 2019] Manly had provided a lucid dismissal of the ‘gunpowder cipher’ in 1931, writing:

a) The Gunpowder Formula. The briefest and simplest case of a decipherment obtained from a text not written by Roger Bacon is furnished by the famous ‘Gunpowder Formula’.. Here, in a letter attributed to Bacon, occurs, according to Brewer’s reprint from the printed text of 1542, the famous: ‘Sed tamen sal petrae LURU VOPO VIR CAN UTRIET sulphuris; et sic facies tonitruum et coruscationem, si scias artificium.’ I shall not now insist upon the probability that the last three chapters of this epistle are not the work of Bacon, or upon the fact that without any warrant Professor Newbold took a well-known symbol for Sed as Sume. The important fact is that the letters LURU VOPO VIR CAN UTRIET are not found in any extant MS., but are apparently due to a misreading of the distorted Greek letters occurring at this point in the MS. from which the 1542 edition was printed. Yet applying his system to this misreading, which originated more than three centuries after the death of Bacon, Professor Newbold got a thoroughly satisfactory decipherment.

  • John Matthews Manly, ‘Roger Bacon and the Voynich MS’, Speculum, Vol. 6, No. 3 (Jul., 1931), pp. 345-391.


  • an anonymous but informative website on the history of gunpowder is here.


How did Bacon come to know something.. anything… of gunpowder,?

In terms of European knowledge, the usual opinion is that he learned it from Friar Berthold, or vice versa.  Not that the question has any demonstrable relevance to study of Beinecke MS 408,  but Needham’s view was that:

… Perhaps the most extraordinary fact is that all the stages, from the incendiary uses of the mixture right through to the metal-barrel hand-gun or bombard, with the projectile fully occluding the bore, were passed  through in China, before Europeans knew of the mixture itself. Probably there  were three comings. Roger Bacon by c.1260 or so was able to study fire-crackers, doubtless [sic] brought west by some of his brother friars; and the Arabian military engineers in the Chinese service must have let Hasan al-Rammah know about bombs and rockets by  c.1280. Then, within the following twenty years, came the cannon, quite possibly directly overland through Russia.

  •      Needham, op.cit., p. xxxi.


See also:

  • Lynn Thorndike, ‘The True Roger Bacon’ published in two parts in  The American Historical Review. Part 1 in Vol. 21, No. 2 (Jan., 1916), pp. 237-257; Part 2 in Vol. 21, No. 3 (Apr., 1916), pp. 468-480.
  • the current version of the wiki biography for Roger Bacon is good.(Dec. 2018)


Next post: The Military Cryptanalysts (Prelude).

Wheat from Chaff – Books of Secrets and the ‘Secretum secretorum’

Header picture:     (detail)  Brit.Lib. MS Harley 3719  f.31v  (1275-1540), excerpt from the Secretum Secretorum
This post follows from ‘Wheat from Chaff – ‘Bacon ciphertext’ (Dec.15th., 2018)


…  investigat secreta naturae …- Roger Bacon, Opus Maius, II

As we do what Wilfrid should have done, testing his assertions severally against the secondary  evidence and the manuscript’s own testimony  –  it becomes clear that Wilfrid’s “history” for the manuscript is anything but. His failure to establish the truth of what he said about the manuscript  before making those assertions public – and the failure of others to do so before adopting them, meant that the manuscript’s study was misdirected from the first, and researchers diverted into innumerable dead-ends simply because their first premises – their ‘givens’ – were groundless.  The habit is still widespread by which  a fictional narrative ( habitually if wrongly called ‘theory’) is first promoted and  its success thereafter evaluated  by the number of believers – but not  by what demonstrable value it has for a more accurate understanding of the manuscript – not of its materials, nor of what it was intended to convey. We’ll look at this in more depth when considering false analogies, false equivalents and ‘argument from association’. (List of logical fallacies)

His imagining the text written in Bacon’s own hand is unjustified.   To suppose   Bacon or anyone else might encipher an entire book about  ‘natural history’ in the mid-thirteenth century runs counter to the historical evidence; there is no evidence to support the idea that Bacon ever enciphered an entire book, either  – not about natural history or anything else.  And the content which Wilfrid imagined (‘natural history’) cannot be accepted at face value,  given the lack of evidence for Bacon’s ever being afraid to speak of such matter  and the wide enthusiasm which met Cantimpré’s book on that subject – despite its using Aristotle and being written in 1230-1245, during the ‘ban’ years:  (see previous post).

To believe that Voynichese is unreadable because written in a Baconian cipher demands, today, not only suspension of disbelief but its elevation beyond this mortal world –  for if Bacon’s methods of encryption were unsophisticated, modern decryption algorithms are not.  And there is the other point – that whether or not our present manuscript was made in Latin Europe, there is no way to know yet where the content was first enunciated, nor whether the text’s underlying language (if any) is European.  Such things are also treated as ‘givens’ – maintained without critical scrutiny since 1921 and despite the very obvious fact that if the text or the imagery conformed to Latin European practice, the latter, in particular, would not have proven illegible in those terms – for a century.

And finally, as we’ve seen,  Bacon’s sentence from De secretis..  (‘he’d be a fool….’ ) is neither a text’s justification nor the manifesto which it is so often portrayed as being.  It is, rather, part of an introduction to a subject  which Bacon thought might prove useful at some later time.

On the other side of the scale, one item is potentially in favour. Bacon was much impressed by the Secretum Secretorum. It can be called a book of secrets, was attributed to Aristotle and its title might suggest a need to keep its content secret, even though it is just as much a text in the tradition of the ‘Mirrors of Princes’.


‘Books of Secrets’ genre.


Eamon describes it:

… To the modern reader expecting to encounter some mysterious, arcane wisdom, these works are bound to be disappointing. What was revealed, typically, was not the lore of ancient sages or magi, but recipes, formulae, and “experiments”, often of a fairly conventional sort, associated with one of the crafts or with medicine: e. g., quenching waters for hardening steel, recipes for dyes and pigments, instructions for making drugs, and “practical alchemical” formulae such as a jeweller or tinsmith might use. When a medieval or sixteenth century writer claimed to have discovered a “secret,” he often had this meaning in mind; and when a contemporary library catalogue referred to a “book of secrets,” it usually indicated a compilation of such recipes…

….They exist in countless medieval Latin and vernacular manuscripts, and in printed books of almost every European language. Nor did these writings disappear with the “triumph of modern science” in the seventeenth century. Despite [Thomas] Browne’s warning, books of secrets continued to be written, copied, published, and read by a sizeable portion of the reading public, and by some whom all would agree were among the leading scientific personalities of the day….

  • William Eamon, ‘Books of Secrets in Medieval and Early Modern Science’, Sudhoffs Archiv, Bd. 69, H. 1 (1985), pp. 26-49.


That’s exactly how Roger Bacon understood the matter, too.  His ‘scientist’ is master of practical techniques and know-how –  as we see in Bacon’s letter to Pope Clement (1267):

Hence he  has peered into all the processes of smelters, of goldsmiths, of silversmiths, and of other workers in metals and minerals; he knows everything pertaining to war, weapons and hunting; he has examined everything pertaining to agriculture, surveying and other occupations of the countryman; he has even taken into consideration the experiments of witches and their fortune-telling and charms and those of magicians in general, likewise the tricks and illusions of legerdemain — so that nothing worth knowing might remain unknown to him and that he might know what to condemn as due to sorcery or magic.

Nick Pelling is among those who have  believed  that the Voynich manuscript may be a ‘book of secrets’.  For details see (e.g.)


“Confounding demons”       detail from folio 51r,   Brit.Lib. Yates Thompson MS 28

Aristotle’s  ‘Secretum Secretorum’:

Today we deny Aristotle’s authorship, but Bacon and his successors did not, so I have omitted ‘pseudo-‘ from the heading.

One reason Bacon expended so much energy on his project  [an edition and commentary on the ‘Secretum Secretorum’] is that he valued [the text] as possibly Aristotle’s greatest production. Not only did it impart sage counsel on issues of morality, politics, and health: Bacon, for example, ate rhubarb on the Secretum‘s advice, and felt much the better for it!   In addition, Bacon believed the Secretum treated important subjects deliberately omitted in the books Aristotle wrote for a general audience.

  • quoted from Steven J. Williams, ‘Roger Bacon and His Edition of the Pseudo-Aristotelian Secretum secretorum’, Speculum, Vol. 69, No. 1 (Jan., 1994), pp. 57-73.. the passage  is pp. 64-65.


Origin of the Latin versions:

Salim Abu l-ʿAla’, secretary to the caliph Hisham ibn ʿAbd al-Malik (r. 724–743), initiated the translation of the pseudo-Aristotelian letters on government to Alexander the Great.  This collection forms the nucleus of the most famous among the “mirrors for princes”, the Sirr al-asrar…, known in the Latin Middle Ages and early modern times as the Secretum secretorum. One of the Arabic translations of the pseudo-Aristotelian De Mundo also traces back to this period… However, it was under the ʿAbbasids (750–1258), and in particular in the first two centuries of their caliphate, that the translations blossomed.

A different account is given by Robert Steele,

In the introduction to the work as we now have it we are told that it was translated from Greek into Rumi, and from Rumi into Arabic, by Yuhanna ibn el-Batrik (or Ibn Yahya al-Batrik). Rumi is the common word for Syriac, when it does not mean Greek, and Yuhanna, who died a.d. 815, was a well-known translator, physician of Al- Ma’mun, who is said to have rendered the Politics and the Historia Animalium into Syriac, and the De caelo et mundo and the De anima in epitome, with other works, into Arabic. There does not seem anything obviously unlikely about the statements that a Syrian text has existed, and that it was translated into Arabic about the beginning of the ninth century by Ibn al-Batrik, while it is to be hoped that English scholars, at any rate, have dropped the pose that a manuscript attribution is a decisive argument against the supposed author or translator having any connexion with the work.

A curious confirmation of the possible existence of a Syriac version has lately turned up in the publication by Dr. Budge of a thirteenth-century collection of medical treatises and receipts in Syriac (Syrian Anatomy, Pathology, and Therapeutics, 2 vols., London, 1913). Among them (ii. 540) is the formula for calculating victory by taking the numerical value of the names of the generals and casting out the nines (see pp. Ix, 250). This formula is identical with one which exists in both forms of the Arabic text, though it is omitted in the Vulgate Latin version.

It is unlikely that the Syriac text, if it should ever be found, will bear the name of the Secret of Secrets. Perhaps the traditional name preserved by Al-Makin, The Book of the knowledge of the ‘ Laws of Destiny, or the Kitab-al-siyasa of Ibn Khaldun, its alternative title in Arabic, may afford some clue.

  • Roger Bacon, Robert Steele, Opera hactenus inedita Rogeri Baconi V: Secretum Secretorum (1909) Latin text; Steele’s notes in Eng.
  • Roger Bacon, Opera hactenus inedita Rogeri Baconi, 5: Secretum secretorum cum glossis et notulis, ed. Robert Steele (Oxford, 1920).

See also:

  • Steven J. Williams, The Secret of Secrets: The Scholarly Career of a Pseudo-Aristotelian Text in the Latin Middle Ages. (2003).
  • Yela Schauwecker, Die Diätetik nach dem ‘ Secretum secretorum * in der Version von Jofroi de Waterford Teiledition und lexikalische Untersuchung, Würzburger medizinhistorische Forschungen 92   (Würzburg: Königshausen & Neumann, 2007).

Yela Schauwecker here presents us with an Old French translation of those sections of the pseudo-Aristotelian ‘Secretum secretorum’ pertaining to diatetics, detailing which items are beneficial for each part of the body, and the qualities of various foodstuffs.  The edited text also features the much briefer passages which precede these and which relate to the benefits of doctors, prayer and astrology.   The translation is of particular philological interest because it involves the collaboration of an Irish Dominican author (Geoffrey of Waterford), composing in Anglo-Norman, and his Walloon scribe, Servais Copale. Until recently, Schauwecker’s base manuscript BNF, fr. 1822 was believed to be the only extant manuscript preserving Geoffrey’s translation.

  • quoted from the review by Alex Stuart in  Medium Aevum, Vol. 79, No. 1 (2010) EDITIONS OF TEXTS, pp. 160-169. passage occurs on p.167.


  • L. Saif,  ‘Textual and Intellectual Reception of Arabic Astral Theories in the Twelfth Century’, in  The Arabic Influences on Early Modern Occult Philosophy. (2015)
  • Lynn Thorndike, ‘The Latin Pseudo-Aristotle and Medieval Occult Science‘,  The Journal of English and Germanic Philology, Volume 21 No.4 (April 1922) pp.229-258.
  • M. Gaster, ‘The Hebrew Version of the “Secretum Secretorum,” a Mediæval Treatise Ascribed to Aristotle’.  Journal of the Royal Asiatic Society of Great Britain and Ireland (Oct., 1908), pp. 1065-1084 .
  • [pdf] Antònia Carré and Lluís Cifuentes, ‘Girolamo Manfredi’s Il Perché: II. The Secretum secretorum and the book’s publishing success’Medicina & Storia, X, 2010, 19-20, n.s., pp. 39-58.
  • Linda T. Darling, ‘Mirrors for Princes in Europe and the Middle East: A Case of Historiographical Incommensurability’ (no publication details given; paper available through academia.edu).


Next post: Bacon’s De Secretis in re  Hime’s “gunpowder cipher”