# Reference request concerning an alleged Jewish contribution to the early theory of light refraction, and to the first geometry textbook in Europe

Page 50 of the book

Gustav Karpeles: A Sketch of Jewish History. Translated from the German [by an anonymous translator]. The Jewish Publication Society of America. 1897.

contains the following interesting though unsourced boast:

"A Jew was the first to study the refraction of light ; a Jew introduced to Europe the famous work of Dioscorides, the foundation of the whole science of botany ; a Jew wrote the first textbook of geometry in Europe [...]" $${}\hspace{24.76em}$$(B)

For a historical research project, I need to know:

Question. Which three Jews did Karpeles refer to in (B)?

(I am mostly interested in the first and the last of the three contributions alleged, whence my headline for this question.)

Remarks.

• I made considerable efforts of looking through reference works and online sources, but in none of the three separate domains (1) light refration, (2) Dioscorides' writings, (3) geometry textbooks, did I find references to significant Jewish involvement in the early stages. (Except perhaps in the case of Karpeler's least interesting claim, the one about Dioscorides: it is well known that there were many Arab and Jewish translators of Greek scientific texts around the Mediterranean, from islamized Spain all the way to Greece, and one of those translators probably was on Karpeler's mind.) What I am interested in for the most part are (1) and (3). In the case of (1), Alhazen, of course, is being mentioned a lot as an early contributor to the study of light, but as far as I know, Alhazen was not Jewish, not even secretly so. In the case of (1) and (3) I still have no inkling of whom Karpeler is referring to.

• As already mentioned, Karpeler's book does not contain any sources or references, not even for any other statement in the short book; this has a systematic reason: in the foreword, the book is said to be a translation of stenographic notes of a lecture given by Karpeler in the winter of 1895/1896 in a B'nai B'rith lodge in Berlin; as such, it is not meant to be a carefully referenced work, but rather has some degree of pep-talk-flavor mixed to it; still, Karpeler's three claims stand and call for an explanation. (If Karpeler's claims turn out to be untenable, there still remains the minor sub-question of whether Karpeler's statements were made from whole cloth, or whether he mixed up some names and e.g. thought of Alhazen as a Jew.)

• I'm voting to close this question as off-topic because this is political rather than scientific. The definition of "Jew" varies from religious to ancestral depending on the level of either vitriol or orthodoxy – Carl Witthoft Jan 22 '19 at 13:39
• It is very unfortunate that in many 19th century books that many early Arab or Jew scientists were depicted as mere translators of Greek works. No wonder why those authors cannot name any translators! Translation is a part of any vibrant scientific culture and continues to happen today in all sciences! – M. Farooq Jan 27 '19 at 2:22
• Dear @CarlWitthoft: thanks for your input. Personally, I disagree with the statement that this was a political question. The definedness of some of the terms of the question isn't significaly lower than plenty of other questions in this forum. I asked because I was unable to make sense of Karpeles' assertion even 𝘳𝘦𝘭𝘢𝘵𝘪𝘷𝘦 to using very loose definitions of the relevant terms. Further, I think that a necessary condition for any question to be classified as 'political' is that it concerns the 𝘧𝘶𝘵𝘶𝘳𝘦; this question, however, is strictly about the past, hence cannot be 'political'. – Peter Heinig May 25 '19 at 16:40
• Well, Peter, I'm sure you remember the famous saying which starts "He who controls the present, controls the past..." . – Carl Witthoft May 27 '19 at 22:32
• Trying to make sense of Karpeles' statement, I found a tangentially-relevant mathematical innovation which apparently was first introduced to Europe by a Jewish scholar: it is claimed in at least two sources that "Sefer ha-Mispar" (of Abraham ibn Ezra) was the first book to introduce the decimal system to Europe. E.g., Shlomo Sela writes in Footnote 10 of doi.org/10.1007/978-94-015-9389-2_8 that "Sefer ha-Mispar brings an outstanding mathematical novelty to Western Europe: the decimal positional system. I did not find anything on optics, botany or geometry though. – Peter Heinig Sep 10 '19 at 17:29