Galileo and His Sources: Heritage of the Collegio Romano in Galileo's Science

by William A. Wallace

Overview

William A. Wallace demonstrates the importance of two early manuscripts of Galileo dismissed by earlier researchers as juvenile exercises. Analyzing all his scientific writings from the late 1580s to 1610 and from 1610 to 1640, this book illuminates both the sources and the evolution of Galileo's thought.

Originally published in 1984.

The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These editions preserve the original texts of these important books while presenting them in durable paperback and hardcover editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.

Product Details

ISBN-13:	9780691640129
Publisher:	Princeton University Press
Publication date:	04/19/2016
Series:	Princeton Legacy Library , #438
Pages:	388
Product dimensions:	6.10(w) x 9.30(h) x 1.00(d)

Read an Excerpt

Galileo and His Sources

Heritage of the Collegio Romano in Galileo's Science

---

By William A. Wallace

PRINCETON UNIVERSITY PRESS

Copyright © 1984 Princeton University Press
All rights reserved.
ISBN: 978-0-691-08355-1

---

CHAPTER 1

Sources of Galileo's Logical Questions

Much is already known about the life of Galileo Galilei, particularly his discoveries and the polemics surrounding the publication of his principal works on astronomy and the science of mechanics. Considerably less is known about his early period, that from his birth at Pisa in 1564 to his perfection of the telescope at Padua in 1609, when the intellectual foundations were laid for most of his later work. Historians are aware that his preliminary studies were made at the Monastery of Vallombrosa near Florence, after which he entered the University of Pisa in 1581 with the intention of pursuing a career in medicine. It is known that he left the University of Pisa in 1585 without obtaining a degree, apparently to pursue a new-found interest in mathematics. By 1589 he had achieved sufficient status to obtain a lectureship in mathematics at the University of Pisa, where he taught until 1591. The next year he moved to the University of Padua as professor of mathematics, to succeed Giuseppi Moleti, and there he remained for eighteen years, doing research on the science of motion that has recently been fairly well documented. What he accomplished before he moved to Padua is considerably more problematic. Several treatises ostensibly composed by him at Pisa are still extant: a mathematical treatise, in Latin, on the center of gravity of solids; a smaller work, in Italian, on "the little balance" (La Bilancetta); some measurements of specific gravities and a few notations on a text of Archimedes; and, finally, a fairly extensive series of Latin compositions dealing with questions on logic, on the universe and the elements, and on local motion.

These last-named Latin compositions have been the subject of recent study, the fruits of which set the theme for this volume. They are conserved in three manuscripts now in the Galileiana Collection of the Biblioteca Nazionale in Florence, all written in Galileo's hand. These are: MS 27, containing questions based on Aristotle's Posterior Analytics, henceforth referred to as the logical questions (LQ); MS 46, containing questions relating to Aristotle's De caelo and De generatione, henceforth referred to as the physical questions (PQ), and some memoranda on motion; and MS 71, containing drafts of a dialogue and some treatises on local motion, usually referred to as the De motu antiquiora so as to distinguish it from other tracts De motu composed by Galileo in later life. The first two manuscripts show signs of being derived and possibly copied from other sources, whereas the third contains more independent compositions, though these are now known to draw extensively on the memoranda on motion in the second manuscript.

The previously accepted evaluation of these three manuscripts — one requiring substantial revision in light of the latest research — derives from Antonio Favaro, the editor of the National Edition of Le Opere of Galileo, whose first volume appeared in 1890.3 In that volume Favaro decided to publish only the second and third manuscripts, the second (MS 46) under the title Juvenilia and the third (MS 71) under the title De motu. The first manuscript (MS 27), for reasons that historians of medieval and Renaissance science find hard to understand, he effectively excluded from the National Edition, providing only a brief description and some excerpts in volume 9 under the title Saggio di alcune esercitazioni scolastiche di Galileo. Apparently Favaro was himself unacquainted with Aristotle's Posterior Analytics and we knew nothing of the role played by this work in the development of scientific methodology. Reading Viviani's reconstruction of Galileo's life, written in 1654, he therefore focused on a statement to the effect that Galileo received instruction in logic from a priest-instructor of Vallombrosa (un Padre Maestro Volambrosano), but that his fine intellect found such matter tedious, fruitless, and unsatisfying. This, plus a few errors in Latinity, persuaded Favaro that these were merely scholastic exercises and thus of no value in understanding Galileo's later work. The second manuscript (MS 46) he accorded slightly more value because he believed that it could be dated, on the basis of internal evidence, as written in 1584, while Galileo was a student at the University of Pisa. Thus he transcribed and published it as a "youthful work," which he believed was based on lectures of Francesco Buonamici and other professors who taught at Pisa while Galileo was studying there. Only the third manuscript (MS 71) did Favaro regard as meriting serious attention, since it was clearly related to Galileo's later work on motion. This he dated, following a well-documented tradition, as written "around 1590," while Galileo was already teaching mathematics at the University of Pisa.

The surprising discovery of the past two decades is that the foregoing chronology is quite wrong. Rather than have the three manuscripts date from various periods in Galileo's life at which he would have been 15, 20, and 26 years of age, respectively, there is now considerable evidence to show that they were all written in conjunction with his first teaching appointment at the University of Pisa and so date from the years 1589 to 1591. This revision leaves intact the time of composition of MS 71 as "around 1590," but it reinstates the notation of an early curator of the Galileiana manuscripts to the effect that the physical questions of MS 46 were composed "around 1590" also. The logical questions of MS 27, finally, must have preceded the contents of the other two manuscripts, but not by much, since it can be shown that they could not have been written before late 1588 or early 1589. Such proximity in time of composition encourages one to investigate the many internal relationships between them, as well as their cumulative influence on Galileo's later writings, and it is such an investigation that constitutes the burden of this volume.

The evidence for the new datings of MSS 27 and 46 is quite complex, requiring considerable textual analysis and comparison to give it probative force. Since the character of this evidence changes for the two manuscripts, it is thought best to present it in two chapters: that for the logical questions in this first chapter and that for the physical questions in the next. This procedure has the advantage that material common to both analyses can be covered at the outset, and the evidence for dating the logical questions can then be added to that for dating the physical questions, which offers slightly more difficulty and so can benefit from this help. The accepted dating of MS 71 is not at question here, as already noted, and thus discussion of that manuscript is reserved for part 3 of this study, where it is situated with respect to Galileo's other early writings.

The technique employed in these two chapters of part 1 consists of showing that both sets of questions are derived or extracted from various writings of Jesuit professors at the Collegio Romano dating from the last decades of the sixteenth century. These Jesuit writings are numerous and fall into two categories: some are printed books, others are manuscripts containing lecture notes for the courses then being taught at the Collegio. For the first, the authors and the dates of publication are easy enough to identify, although there is one case of plagiarism pertaining to the logical questions that complicates the reasoning employed in its instance. For the second, the problems are more numerous: the possible manuscript sources are many; in a few instances their authors or their dates of composition are uncertain; and it is quite likely that the manuscripts thus far discovered represent but a small fraction of those that were at one time available. Such difficulties effectively rule out definitive proof that Galileo took his notes from any one Jesuit manuscript or book. The many textual parallels between Galileo's writings and these possible sources, however, leave little doubt, as will be seen, that the logical questions were written around 1589 and the physical questions around 1590. Although printed books have been helpful in establishing the provenance of these questions, the evidence also points to Galileo's having used handwritten rather than printed sources in the composition of both, as will be explained in what follows.

I. Logic at the Collegio Romano

The philosophy curriculum at the Collegio Romano during the period of interest was taught in a three-year cycle, with logic occupying the first year of the cycle, natural philosophy the second, and metaphysics the third. As can be seen from data presented in table 1, it was more or less customary for a professor to begin the cycle with a particular class and then continue along with them throughout the remaining two years. This assured greater continuity in the course, and even allowed a professor to make up, in a following year, material he had been unable to cover in the year assigned. Mathematics was usually studied in the second year, and this additional load, together with the large amount of natural philosophy that was assigned, resulted in a fair amount of that discipline being left over for the third year. Textbooks were probably available for all the courses, but most professors preferred their own teaching notes, and students were encouraged to make reportationes of them for their personal use. Time was in fact set aside for Jesuit scholastics to complete their class notes by referring to those of the professor and other sources. It seems likely that most professors deposited a finished set of lectures in the Collegio library after their course was completed; if so, repeated copying of such codices would explain the large number of reportationes of lectures from the Collegio Romano that are now found in European libraries.

A summary of the best available information about the professors, the courses they taught, and the years in which they taught them at the Collegio is assembled in table I. A gap of five years in the rotulus of professors occurs between the years 1572 and 1577, and there are occasional other lacunae down to 1585, after which the list is complete.

For logic, the first professor on the list is Franciscus Toletus (Toledo), who taught philosophy at the University of Salamanca previous to his entry into the Jesuits in 1558, and had come to Rome while still a novice in the Society to teach logic in the academic year 1559-1560. Toletus is of importance in that his teaching resulted in a series of textbooks, including a complete logic course that became available in 1576 and was reprinted many times to the end of the sixteenth century. This undoubtedly served as the basic text for lecturers at the Collegio during the two decades that followed its initial printing. It also was expanded or supplemented by Ludovicus Carbone of Costacciora, one-time professor at Perugia, who reprinted the text along with his putative emendations under the title Additamenta ad commentaria doctoris Francisci Toleti in logicam Aristotelis at Venice in 1597. The Additamenta, as will be seen, was plagiarized from a course given by Paulus Valla at the Collegio Romano in the academic year 1587-1588. It assumes great importance in this study from the fact that Galileo apparently used the very set of notes Carbone plagiarized when preparing the logical questions of MS 27. Indeed, establishing this connection between Galileo and Valla via Carbone is the primary goal of the textual analyses offered in this chapter.

Considering the large number of professors and the many times logic was taught at the Collegio between 1559 and the end of the century, a surprisingly small number of lecture notes or printed editions have survived to the present day. Those that are known are given in table 2, with an indication of the year in which they were taught, the professor who gave the course, and whether it survives in manuscript or printed form or both. The course offered by Ioannes Lorinus is the only one now extant both in manuscript and in print, and the two versions are practically identical — rather remarkable considering their separation by an interval of some thirty-six years. Valla's printed course, on the other hand, is known to be different from the manuscript version (now lost) that antedated it by some thirty-four years, for reasons that will be explained presently. It is the most complete of the printed texts, filling two large folio volumes and treating in detail practically every subject that can be considered in logic. The remaining courses, those of Vitelleschi, Rugerius, Jones, and Eudaemon, are not as compendious as Valla's, although Rugerius comes closest to it in the quantity of material he covered. Vitelleschi and Jones approximate Lorinus's course in content, though with somewhat different emphases, and Eudaemon offers a less developed treatment, covering the subject in the most cursory fashion of all.

Since each of these courses sheds light on the way logic was taught at the Collegio, and on this account can aid in understanding the materials used by Galileo when writing his logical questions, their respective contents will be sketched before examining Galileo's manuscript in the following section.

a TOLETUS AND CARBONE

Toletus was one of the earliest philosophy professors at the Collegio Romano. There he taught logic, as already noted, in 1559-1560, and then continued on in the philosophy cycle, teaching natural philosophy in 1560-1561 and metaphysics in 1561-1562, after which he passed to the teaching of theology. He achieved great eminence as a theologian and was made a cardinal in 1594, two years before his death. Some of his manuscripts are preserved in the archives of the Gregorian University in Rome, including a commentary on the Posterior Analytics of Aristotle. This is not as complete as the similar commentary contained in the printed edition, and has little interest for its relation to Galileo's text on that account. The logic course that was printed, however, gives a good idea of the extent of the teaching of this subject at the Collegio, and apparently set the syllabus there for the last three decades of the sixteenth century.

Toletus's logic usually appeared in two volumes, the first a slim book of less than one hundred pages entitled Introductio in dialecticam Aristotelis, which contained a quick overview of all of logic, including the essentials of formal logic and topics similar to those contained in the Summulae tradition, and the second a book of some four or five hundred pages entitled Commentaria una cum quaestionibus in universam Aristotelis logicam, which detailed all topics in logic of philosophical interest. As the course at the Collegio developed, the first volume formed the basis for a two-or three-week introduction to the science of logic in which the students were drilled in the uses of terms and the forms of reasoning, so that they would have a general familiarity with the terminology and procedures employed by the logician. The second volume then enabled the professor to build on this foundation and at the same time cover most of the classical texts in logic in lectures extending over the remainder of the academic year. The structure of the second volume is of interest for what follows, and thus is indicated below in schematic form, with an indication of the approximate number of pages allotted to each tract:

A general division of the arts and the sciences, followed by five questions on the nature of logic as a science. (20 pages)

An introduction to the Isagoge of Porphyry, concerned with the "five universals," including a brief commentary on the text, interspersed with questions on the following topics:

Four questions on universals.

Two questions on first and second intentions.

Three questions on the subject of the book, viz., predicables, and how these are divided.

Five questions on genus, two on the individual, one on species, and discussions of disputed points on property and accident. (60 pages)

(Continues...)

---

Excerpted from Galileo and His Sources by William A. Wallace. Copyright © 1984 Princeton University Press. Excerpted by permission of PRINCETON UNIVERSITY PRESS.
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
Excerpts are provided by Dial-A-Book Inc. solely for the personal use of visitors to this web site.

---

Table of Contents

• FrontMatter, pg. i
• Contents, pg. v
• Tables, pg. ix
• Preface, pg. xi
• Chapter 1. Sources Of Galileo's Logical Questions, pg. 3
• Chapter 2. Sources of Galileo's Physical Questions, pg. 54
• Chapter 3. Sciences and Demonstrative Methods, pg. 99
• Chapter 4. The Study of Local Motion, pg. 149
• Chapter 5. Galileo's Earlier Science (Before 1610), pg. 219
• Chapter 6. Galileo's Later Science (After 1610), pg. 281
• Bibliography, pg. 351
• Index, pg. 363