Pseudo-Geber

Geberi philosophi ac alchimistae maximi de alchimia libri tres, 1531, Chemical Heritage Foundation

Geberis philosophi perspicacissimi, summa perfectionis magisterii, 1542

Pseudo-Geber ("false Geber") is the name assigned by modern scholars to an anonymous European alchemist born in the 13th century, sometimes identified with Paul of Taranto, who wrote books on alchemy and metallurgy, in Latin, under the pen name of "Geber".

"Geber" is the shortened and Latinised form of the name Jābir ibn Hayyān, a ninth century Islamic alchemist. In Europe for many centuries it was assumed that "Geber" was identical with Jabir ibn Hayyan and that the books had been translated from Arabic. Arabic alchemy was held in high esteem by medieval European alchemists and so texts attributed to Arabic authors were well regarded. Some Arabic writings attributed to Jābir were translated into Latin during the eleventh to thirteenth centuries. Other Arabic writings attributed to Jābir ibn Hayyān were actually written in Arabic after his death in 815.

The influential theory presented in the Summa perfectionis inspired a succession of publications by fellow European authors who also styled themselves “Geber.” The practice of adopting the name of an illustrious predecessor, pseudepigraphy, was not at all uncommon in the medieval era. Similarly, a wide variety of medieval writings were distributed with the illustrious Aristotle as the stated author, which were not written by the original authentic Aristotle.

The pseudo-Geber corpus and the Geber problem

The following set of books is called the "Pseudo-Geber Corpus" (or the "Latin Geber Corpus"). The books were published by printing-press several times in the first half of the 16th century. They were in circulation in manuscript for roughly 200 years beforehand. The stated author is "Geber" or "Gebri Arabis" (Latin for "Geber the Arab"), and it is stated in some copies that the translator is "Rodogero Hispalensi" (Latin for "Rodger the Hispanic").

• Summa perfectionis magisterii ("The Height of the Perfection of Mastery").
• Liber fornacum ("Book of Furnaces"),
• De investigatione perfectionis ("On the Investigation of Perfection"), and
• De inventione veritatis ("On the Discovery of Truth").

Also:

• Testamentum Geberi
• Alchemia Geberi

Being the clearest expression of alchemical theory and laboratory directions available until then — in a field where mysticism, secrecy, and obscurity were the usual rule — Pseudo-Geber's books were widely read and influential among European alchemists. The Summa Perfectionis in particular was one of the most widely read alchemy books in western Europe in the late medieval period. The next three books on the list above are shorter, and are, to a substantial degree, condensations of the material in the Summa Perfectionis. The last two books listed, Testamentum Geberi and Alchemia Geberi, are "absolutely spurious, being of a later date [than the other four]", as Marcellin Berthelot put it, and they are usually not included as part of the Pseudo-Geber corpus. Their author is not the same as the others, but it is not certain that the first four have the same author either.

As mentioned, the Pseudo-Geber corpus was assumed to be translated from Arabic throughout the medieval and renaissance periods. This assumption was reversed in the late 19th century by the studies of Kopp, Hoefer, Berthelot, and Lippmann. The corpus is clearly influenced by medieval Arabic writers (especially by Al-Razi, perhaps more so than the eponymous Jabir). The estimated date for the first four books is 1310, and they could not date from much before that because no reference to the Summa Perfectionis is found anywhere in the world before or during the 13th century. For example there is no mention in the 13th century writings of Albertus Magnus and Roger Bacon. No Arabic copies have been found. Their contents reflect the state of knowledge in Europe at about 1300. The chemistry historian J.C. Brown asserted in 1920: "An important point of evidence is the absence in the Arabic texts of the new and original facts recorded in the Latin particularly... nitric acid, aqua regia, oil of vitriol, silver nitrate...." Aqua regia is a mixture of nitric acid and hydrochloric acid. Vladimir Karpenko and John A. Norris, in 2001, assert that its first documented occurrence is in Pseudo-Geber. In 2005, the historian Ahmad Y. Al-Hassan pointed out that earlier Arabic texts, prior to the 13th century, attributed to authors such as Jabir and Al-Razi, already contained detailed descriptions of substances such as nitric acid, aqua regia, vitriol, and various nitrates.

The identity of the proposed Latin author remains a mystery. He may have lived in Italy or Spain, or both. Some books in the Geber corpus may have been written by authors that post-date the author of the Summa Perfectionis. As mentioned already, the contents of most of the other books in the corpus are mostly recapitulations of the Summa Perfectionis. The one entitled De Inventione Veritatis, though mostly a recapitulation of Summa Perfectionis, has the earliest known recipe for the preparation of nitric acid." The 1991 book by William R. Newman, The Summa perfectionis of Pseudo-Geber: A critical edition, translation, and study, has 250 pages of critical introduction, followed by 400 pages of footnoted Latin text and 150 pages of footnoted English translation. The critical introduction argues that the author of the Summa perfectionis was Paul of Taranto.

The chemistry historian Eric John Holmyard studied the Arabic and Latin corpuses more extensively and criticized Berthelot's original hypothesis. On textual grounds, Holmyard argued that the Latin corpus has Arabic origins. In 1924, Holmyard stated: “[Berthelot] deliberately wanted to underrate Jābir […], the choice of Jābir’s works made by Berthelot is entirely misleading.” He also stated: “It is here that Berthelot’s ignorance of Arabic led him astray. As a matter of fact, the Summa is full of Arabic phrases and turns of speech, and so are the other Latin works”. In his 1957 book Alchemy, however, Holmyard wrote:

The question at once arises whether the Latin works are genuine translations from the Arabic, or written by a Latin author and, according to common practice, ascribed to Jabir in order to heighten their authority. That they are based on Muslim alchemical theory and practice is not questioned, but the same may be said of most Latin treatises on alchemy of that period; and from various turns of phrase it seems likely that their author could read Arabic. But the general style of the works is too clear and systematic to find a close parallel in any of the known writings of the Jabirian corpus, and we look in vain in them for any references to the characteristically Jabirian ideas of "balance" and the alphabetic numerology. Indeed for their age they have a remarkably matter of fact air about them, theory being stated with a minimum of prolixity and much precise practical detail being given. The general impression they convey is that they are the product of an occidental rather than an oriental mind, and a likely guess would be that they were written by a European scholar, possibly in Moorish Spain. Whatever their origin, they became the principal authorities in early Western alchemy and held that position for two or three centuries.

In 2004, the chemistry historian Maurice P. Crosland concluded that the question of Geber's identity, whether he is the original Jābir or a "pseudo-Geber" adopting his name, is "still in dispute", but then proceeds to refer to Geber as "a Latin author". In 2009, the chemistry historian Ahmad Y. Al-Hassan criticized Berthelot's original hypothesis and, on textual grounds, argued that the Pseudo-Geber Corpus was originally written in Arabic. Al-Hassan criticized Berthelot's lack of familiarity with the complete Arabic corpus and pointed to various Arabic Jabirian manuscripts which already contain much of the theories and practices that Berthelot previously attributed to the Latin corpus.

Contents of the pseudo-Geber corpus

Its author assumed that all metals are composed of unified sulfur and mercury corpuscles and gave detailed descriptions of metallic properties in those terms. The corpus explained the use of an elixir in transmuting base metals into gold (see philosopher's stone) and defended alchemy at length against the charge that transmutation of metals was impossible. The practical directions for laboratory procedures were so clear that it is obvious the author was familiar with many chemical operations. It contains early recipes for producing mineral acids, much like the Arabic corpus. It was not equaled in chemistry until the 16th century writings of chemist Vannoccio Biringuccio, mineralogist Georgius Agricola and alchemist Lazarus Ercker.

See also

• Alchemy
• Alchemy and chemistry in medieval Islam
• Jābir ibn Hayyān
• Kitab al-Kimya