GALILEI, GALILEO

Florentine philosopher, physicist, and inventor; most commonly remembered for his condemnation by the Holy Office as a result of his attempting to prove the Copernican theory of the universe; b. Pisa, Italy, Feb. 15, 1564; d. Florence, Jan. 8, 1642. The family name had originally been Bonajuti, but it had been changed in the 15th century to Galilei in honor of Galileo Bonajuti, a famous physician. The fortunes of the Galilei family had declined by the time Galileo was born. His father, Vincenzio Galilei, was a noteworthy, though impoverished, musician. At the age of 12, Galileo was enrolled in the monastery school at Vallombrosa. Subsequently, it seems, he entered the Vallombrosan order as a novice, but was withdrawn by his father before completing his novitiate training. In 1581 he entered the University of Pisa to pursue the liberal arts course as a prerequisite for entering the school of medicine. After four years of study, Galileo, who by then was more interested in mathematics and science than in medicine, had to withdraw from the university without completing his courses or graduating. He continued to study privately and began to write. In 1586 he wrote a treatise on the hydrostatic balance (La Bilancetta ), and two years later he produced a work on the center of gravity in solids. By then he had attracted the attention of a wealthy patron, the Marquese Guidobaldo del Monte (1545–1607), who was also a very capable mathematician. Guidobaldo used his considerable influence to have Galileo appointed as a lecturer in mathematics at the University of Pisa.

Galileo seems to have made many enemies among the faculty members at the university. Although he probably taught within a framework of traditional mathematics and science, apparently he was not afraid to disagree with the standard doctrine when he had reason to do so. Although it is doubtful that Galileo ever did drop bodies of unequal weight from the Leaning Tower of Pisa to demonstrate that velocity of fall does not vary according to weight as Aristotle taught, the story does exemplify Galileo's spirit. To understand the opposition that Galileo faced at Pisa and throughout his life, it is necessary to review briefly the state of philosophy as generally taught in the universities of his time.

Philosophical Climate. It must be remembered that the philosophy of aristotle was the predominant system of thought in the 16th century. It had been introduced to the Western world in only the 13th century, but in a relatively short time it became the most widely accepted system, partly because of the commentaries of St. thomas aquinas and the scholastics. Aristotelian philosophy presented a logical, clear, and rational explanation of man and the world around him. By the 16th century, philosophical disputes more often than not were between schools advocating different interpretations of Aristotle. Scholastics, Averroists, and Alexandrists all claimed true intellectual descent from the Stagirite. Moreover, under the influence of Renaissance humanism, the tendency to attribute definitive authority to the texts of Aristotle grew even stronger, and philosophical writings were generally more textual and philological than original or creative. Intramural disputes on the interpretation of Aristotle replaced the empirical approach that Aristotle himself had championed centuries before as the beginning of philosophy.

The result was that those who opposed Galileo in the name of Aristotelian philosophy were neither Aristotelian in spirit nor philosophers in the true sense. Galileo described them as people who think that "philosophy is a sort of book like the Aeneid or the Odyssey, and that the truth is to be sought not in the universe, not in nature, but by comparing texts." Galileo's willingness to speak out against Aristotle whenever he thought it necessary, coupled with the fact that he had never graduated from the university and had no academic degree, led his Aristotelian opponents on the faculty to oppose him bitterly as an upstart who dared to challenge their authority and that of "the Philosopher."

In 1592, after two years of teaching at Pisa, Galileo resigned. He returned to his family, then living in Florence and, when his father died, took over the duties of supporting them. Guidobaldo del Monte again came to Galileo's aid, and within a few months he was appointed by the Venetian senate to the chair of mathematics at the University of Padua, a post he held for 18 years. Soon after moving to Padua, Galileo began living in concubinage with a woman named Marina Gamba, who bore him a son, Vincenzio, of whom little is known, and two daughters, both of whom became nuns. Sister Marie Celeste was Galileo's greatest consolation during the trying years that followed.

Padua provided a congenial atmosphere for Galileo. It had a tradition of true philosophical inquiry as witnessed by the fact that 15th-century Paduans such as Paul of Venice, Gaetano da Thiene, and Johannes Marlianus had made significant changes and developments within the framework of Aristotelian science. There Galileo invented a thermometer, wrote many treatises dealing with his ideas and experiments in mechanics, and became deeply interested in astronomy.

Theories of the Universe. Through the ages, the geocentric system of the universe had been almost universally accepted. It had received its doctrinal formulation in the writings of Aristotle (378–322 b.c.) and ptolemy (fl. 150 b.c.). Both agreed that the earth was the motionless center of the universe; but whereas Aristotle accounted for celestial motions by postulating a squadron of concentric spheres to carry the planets and fixed stars around the earth, Ptolemy described the motions of the heavens in terms of eccentric spheres and epicycles. Elements of the Aristotelian and Ptolemaic views were combined in a treatise by john de sacrobosco (d. 1256) and the resulting eclectic system won widespread acceptance. The system did save the appearances, and it had physical support in the Aristotelian concepts of the quintessence,

the circular character of celestial motion, and the First Mover. It is true that there had been some opposition to the geostatic explanation. nicholas oresme, in the 14th century, conceived of a rotating earth at the center of an otherwise motionless universe. Cardinal nicholas of cusa, in his Docta ignorantia (1440), supported Oresme's theory with a few modifications of his own. But it was not until Nicolaus copernicus (1473–1543) that a rival system was sufficiently well formulated to challenge the Aristotelian-Ptolemaic position. In his great work De revolutionibus orbium coelestium (1543), Copernicus advocated a sun-centered universe in which the earth was a planet that revolved both on its axis and around the sun. Copernicus probably believed that his system described the real motions of the heavens, but, largely because of a spurious preface inserted in the De revolutionibus by Andreas osiander in order to avoid religious opposition to the new system, it was commonly thought that Copernicus himself believed his system to be only a mathematical hypothesis and not necessarily representative of the actual constitution of the universe. Even though Copernicus had been unable to free himself of the idea that celestial motion must be circular and was therefore forced to employ eccentrics and epicycles, his system was a slight gain in simplicity over Ptolemy's. Galileo studied the De revolutionibus and, writing to Johann kepler in 1597, acknowledged that he had discarded the Ptolmaic position several years before and believed in the reality of the Copernican system. It was to be the passion of his life to demonstrate the truth of the new astronomy.

The Telescope. In 1608 a Dutchman, Hans Lippershey of Middleburg (1570?–1619), invented a fairly reliable telescope. When Galileo heard of the invention a year later, he began to construct one of his own. Within a short time, he built three telescopes, the largest of which made objects appear nearly 1,000 times larger and 30 times closer than when seen with natural vision. With this instrument Galileo searched the heavens. He made astounding discoveries, the most important of which were reported in his Sidereus Nuncius, or Starry Messenger (1610). In this work, which made him famous, Galileo revealed that the moon was not a perfect sphere as had been thought, but was marred with mountains and valleys. The Milky Way was seen to consist of a multitude of stars invisible to the naked eye. Most important, Galileo announced that the planet Jupiter had four moons revolving around it. These satellites of Jupiter could serve to answer an objection made against the Copernican theory to the effect that if the earth moved through space it would leave the moon behind. Here was a planet traveling a major orbit and carrying four moons with it. Galileo dedicated his Starry Messenger to Cosimo II de Medici (1590–1621), the Grand Duke of Tuscany. In return, Cosimo appointed him ducal philosopher and mathematician with a salary of 1,000 gold florins a year. Galileo left Padua in July 1610 and moved to a villa at Arcetri, near Florence. There he observed the heavens under the aegis of the Grand Duke.

There were strong reactions to the Starry Messenger. Some saw it as a great contribution to human knowledge, but the university Aristotelians came forth in defense of their master's cosmology. First, they said, no matter what Galileo saw through his telescope, the Copernican system seemed to contradict experience. Anyone with the sense of sight could see the sun rise in the east and set in the west. Second, they pointed out that a moving earth was completely opposed to all the known laws of physics. They had a point; a superior system of physics did have to be established before Copernicanism could win acceptance. Third, Aristotle had said long before that if the earth moved, stellar displacements or parallaxes would be observable, but none had ever been recorded. This was a strong objection, and it remained unanswered until F.W. Bessel (1784–1846) and others determined the parallax of the star 61 Cygni in 1838. Another objection raised was that, taken as a fact and not as a mere mathematical device for aiding astronomers in charting stellar positions, Copernican astronomy contradicted the explicit words of Sacred Scripture.

While the debate went on, Galileo made two more discoveries: the phases of Venus and the sunspots. The only explanation for the fact that Venus changes shape just as the moon does is that Venus moves around the sun and not the earth. The sunspots questioned the Aristotelian doctrine that celestial bodies were composed of an immutable quintessence.

While Galileo was formulating his arguments, he failed to adopt a discovery that might have helped the new astronomy win acceptance. In 1609 Johann Kepler published his Astronomia nova, in which he disclosed that planetary orbits were not circular but elliptical and that the sun is at a focus of the ellipse. This was the very thing needed to clear astronomy of epicycles and the dogma of perfect circles. Although it is fairly certain that Galileo knew of the discovery, he never made use of it.

In December 1610 Galileo received support from an unexpected source. Father Christopher clavius, chief mathematician and astronomer at the Jesuit Roman College, wrote to tell him that the Jesuit astronomers had confirmed all his discoveries. Galileo decided that it was time to go to Rome. If he could secure the support of the Jesuit astronomers, he might be able to win at least unofficial ecclesiastical backing for his position. He arrived in the Holy City in March 1611. His reception was most encouraging. Pope paul v granted him a long audience. Prince Federigo Cesi (1585–1630) appointed him a member of the Accademia de' Lincei, a society devoted to philosophical and scientific studies. The Jesuits of the Roman College held a day of ceremonies in his honor. Galileo returned to Florence in June confident that he had won some support.

Heliocentrism and Scripture. Despite his discoveries, Galileo still had no real proof that the Copernican system was anything more than a theory. His observations militated more against Aristotle and Ptolemy than for Copernicus. Had there been only two alternatives, either the Ptolemaic or Copernican, Galileo, by discrediting the first, would have shown the superiority of the second, but it was not that simple. A third system had been worked out by the Danish astronomer Tycho Brahe in 1588. In Brahe's scheme, the planets revolved around the sun while the sun was revolving around a motionless earth. This system could explain Galileo's chief discoveries, the moons of Jupiter and the phases of Venus, while keeping the earth as the motionless center of the universe.

Back in Florence, Galileo became involved in two minor controversies. One was over the question of why things float or sink; the other was an argument with the Jesuit Christopher Scheiner as to who had discovered the sunspots first and how they were to be explained. The latter dispute prompted Galileo to write his Letters on Sunspots (1613), in which, despite his lack of proof, he endorsed the Copernican system. Cardinal Maffeo Barberini, later Pope urban viii, was one of many who wrote to congratulate the author. The Letters were published in Italian rather than Latin, and the growing controversy now became a popular subject of discussion.

Interest passed from the complex problems of physics and astronomy and came to center on the scriptural difficulties raised by the new system. People wanted to know why Joshua would command the sun to stand still if it never moved anyway. (See Js 10.12–13.) They wondered how a moving earth could be reconciled with the statement that God "fixed the earth upon its foundation, not to be moved forever" (Ps 103.5). Also, they believed that the sun must be in motion, for the Book of Ecclesiastes states that "the sun rises and the sun goes down: then it presses on to the place where it rises" (Eccl 1.5). In December 1613 Galileo heard from Father Benedetto Castelli that these and other texts from Sacred Scripture were being invoked directly against the Copernican system. Galileo wrote a letter to Castelli in which he formulated his ideas on the relationship of the Bible and science. Copies of the letter were made and circulated freely. Now the dispute was in the open. In December 1614 a Dominican, Tommaso Caccini, preached a sermon at S. Maria Novella in Florence in which he strongly condemned the new astronomy. Before long, a copy of Galileo's letter to Castelli was forwarded to the Holy Office for examination. Although the Holy Office judged that the letter contained nothing contrary to the faith, Galileo decided to revise and expand it.

While he was working on this, a Carmelite, Paolo Antonio Foscarini (1565–1616), published a book that attempted to reconcile the Copernican system with Holy Scripture. He sent a copy to Cardinal Robert bellar mine, the leading theologian in Rome, and asked his opinion of it. Bellarmine's Letter to Foscarini expressed the unofficial but quite definite attitude of the theologians toward the new astronomy. Bellarmine admitted that the Copernican system saved the appearances better than the Ptolemaic and therefore could be considered a superior hypothesis, but, he pointed out, it was still not established as a fact. The cardinal explained that one is not allowed to interpret the Scriptures contrary to the common agreement of the Fathers of the Church, and the Fathers seemed to interpret the texts in question literally. To contradict their exegesis was to oppose the truth of the Scriptures themselves. There could be no departure from the interpretation of the Fathers in case of doubt, and there would always be a doubt unless Galileo could produce a true demonstration of his theory.

Bellarmine's opinion was wrong on several counts. First, he should have remembered that, as St. augustine and St. Thomas Aquinas had said long before, the Bible was not intended to teach science and therefore its authority should not be invoked in scientific disputes. Second, although most of the Fathers did think that the earth was immobile and the sun moved, not one of them held that this had to be believed as a revealed truth. Third, although it is true that common interpretation by theologians of a text whose meaning is not defined makes that interpretation highly probable, there is still room for an alternative, if less probable, exegesis. However, Bellarmine demanded a physical demonstration before he would allow any other exegesis.

Galileo presented his position in the revised letter to Castelli, which he entitled A Letter to the Grand Duchess Christina. Galileo ably defended the fact that the Bible was not meant to teach science and that, when referring to the physical world around them, the sacred writers used the common conception of the universe in order to avoid confusing the minds of their readers and making them suspicious of the religious truths that the Holy Texts were meant to convey. However, Galileo then made the mistake of conceding to Scripture superior authority even in science, unless contrary physical arguments were demonstrative. "As to the [physical] propositions which are stated but not rigorously demonstrated, anything contrary to the Bible involved in them must be considered undoubtedly false and should be proved so by every possible means." By granting Scripture precedence over probable physical arguments to the contrary and by his inability to prove the real truth of the Copernican system, Galileo was caught in a logical snare. The issue was still being debated when Galileo decided to go to Rome in December 1615 to plead his case personally. About this time, Cardinal Boniface Gaetani wrote to the Dominican Friar Tommaso campanella, asking his views on the dispute. Campanella responded by writing an eloquent plea for scientific freedom entitled Apologia pro Galileo; and although it was undoubtedly the best theological analysis of the problem written at the time, it went largely unnoticed.

First Condemnation. Galileo's conduct in Rome was incredibly bold. He felt he had to convince anyone who would listen that his arguments supported "realist" Copernicanism. What particular incident brought the issue to a climax is a subject of debate; but early in 1616 Pope Paul V thought that the whole matter was getting out of hand, and he ordered the Congregation of the Holy Office to look into it. On Feb. 19, 1616, two propositions, clumsily worded, but representative of Galileo's position, were sent to a committee of 11 theologians who were consultors of the Holy Office. Five days later, they reported their decision to the authorities of the Holy Office.

Obviously, they agreed with Bellarmine's position. In their opinion the proposition that the sun is at the center of the universe and does not move was "philosophically foolish and absurd and formally heretical, inasmuch as it expressly contradicts the doctrines of Holy Scripture in many places, both according to their literal meaning and according to the common exposition and interpretation of the holy Fathers and learned theologians." As to the proposition that the earth is not the center of the universe, but that it moves with both an annual and daily motion, the consultors were agreed that this deserved "the same censure in philosophy, and, that, from a theological standpoint, it was at least erroneous in the faith." Galileo was ordered to appear before Cardinal Bellarmine and was told not to hold or defend the Copernican position any longer. Then, it seems, the commissary-general of the Holy Office, overzealous in his duty (for he was not instructed to intervene unless Galileo objected to Bellarmine's instruction), stepped forward and gave Galileo an absolute injunction not to hold, teach, or defend his opinion in any way, either verbally or in writing. The report of this meeting, found in the files of the Holy Office, has been the subject of a long controversy. It is quite possible that the commissary-general did serve this strict injunction but that Cardinal Bellarmine, knowing that it had not been called for, told Galileo that he was not bound by it. At any rate, with Galileo's promise to comply with the instructions, the case was closed before the Holy Office.

On March 5, 1616, the Congregation of the Index issued a decree suspending Copernicus's book De revolutionibus orbium coelestium until it could be rendered more hypothetical. (The corrections were made, and it was again permitted to be read within four years.) The decree further condemned outright all books that attempted to reconcile the heliocentric system with Holy Scripture, since that doctrine was "false and altogether contrary to Holy Scripture." The actions of the Holy Office and the Congregation of the Index in no way represented a commitment of the infallible teaching authority of the Church against the new astronomy. The decree of the Index received papal approval only in forma communi and therefore was only the fallible decision of a Roman Congregation. Still it did bind Catholics to at least external observance. The publication of the Index decree gave Galileo's enemies ample material for speculation about the theological orthodoxy of the Florentine scientist. Galileo appealed to Cardinal Bellarmine for a written statement that he could use in self-defense. The cardinal's certificate stated that Galileo had not abjured his opinion, nor had he been given a penance, but that he had been told not to hold or defend the Copernican system as true.

The Dialogue. Galileo returned to Florence discouraged but not defeated. For several years he stayed out of disputes. Then, in 1619, he backed a disciple, Mario Guiducci, in a bitter controversy with the Jesuit astronomer Horatio Grassi (1583–1654) over the nature and course of comets. This was still going on when, in 1623, Pope gregory xv died and Cardinal Maffeo Barberini was elected pope. Barberini, who was a good friend of Galileo and had opposed the actions of the Holy Office in 1616, took the name Urban VIII. Galileo dedicated The Assayer (1623), a polemic against Grassi, to the new Pope and then, a year later, went to Rome to see him. Galileo had six long audiences with Urban; and although the Pope refused to lift the ban against "realist" Copernican writings for fear of undermining the authority of the Congregations, he apparently told Galileo that as long as he treated the subject hypothetically and did not attempt to prove the Copernican system, he could go ahead and write.

Galileo decided to risk everything in the hope that he could demonstrate his theory. He spent most of the next six years (1624–30) working on what he thought would be final and conclusive proof that the Copernican system was true. By means of submission clauses in the preface and conclusion, the resulting book, entitled Dialogue on the Two Great World Systems, was approved by the censors and went to press in 1632. The main argument of the Dialogue was based on an erroneous theory of the tides: a theory that he thought would necessitate the motion of the earth. The other important argument of the book, that based on the motion of sunspots, was also faulty and undemonstrative, but the Dialogue still caused a storm. It was obvious that Galileo had attempted to prove the Copernican system. Not only that, but someone convinced Pope Urban that Galileo had made a fool of him and that he had never intended to heed the Pope's instructions. Urban appointed a special commission of theologians to investigate, and again Galileo was in trouble.

Second Condemnation. The special commission made two main charges against the famous scientist. First, Galileo had treated the Copernican system not as a hypothesis, but as an absolute fact. This was contrary to the decree of the Index and Bellarmine's admonition in 1616. Second, he had been fraudulently silent about a command given him in 1616 by the commissary-general during the audience with Bellarmine, not to hold, teach, or defend the new astronomy in any way, either verbally or in writing. The special commission found a record of this strict injunction in the files of the Holy Office, and news of it came as a surprise, even to the Pope. Galileo, then nearly 70 years old, was ordered to come to Rome.

After a long delay due to illness, he arrived on Feb. 13, 1633. He was received with kindness and given comfortable lodging. He was never imprisoned as some have claimed. During the trial, Galileo would not admit that he had tried to prove the Copernican system in his Dialogue despite the many passages from that book that could be cited to the contrary. Nor did he remember that any command had been given him by the commissary-general in 1616. He produced a copy of the certificate Bellarmine had given him years before, which stated that Galileo had been instructed only not to hold or defend the Copernican doctrine. Moreover, as he pointed out to the judges, his book had an imprimatur. It was a strong defense.

Still, he had disobeyed the decree of the Index, Bellarmine's admonition, and the explicit wishes of the Pope; and it seemed even to those who wanted to treat Galileo leniently that some token punishment was in order. There seem to have been two opposing views among officials in Rome regarding what action was to be taken against the old scientist. Cardinal Francesco Barberini, the Pope's nephew, led those who advocated leniency, but a stronger group wanted to humiliate Galileo completely, and they prevailed. They succeeded in having the Dialogue prohibited (the ban was lifted only in 1822) and in having Galileo condemned as "vehemently suspected of heresy." Galileo was made to kneel and abjure the Copernican opinion, sentenced to imprisonment, and given a "salutary penance" to recite. The prison sentence was never imposed, although Galileo remained under house arrest in Florence for the rest of his life. The condemnation was the act of a Roman Congregation and in no way involved infallible teaching authority, but the theologians' treatment of Galileo was an unfortunate error; and, however it might be explained, it cannot be defended.

Last Days. Upon his return to Florence, Galileo went back to the study of dynamics. In 1636 he finished his greatest work, the Discourses concerning Two New Sciences, a clear statement of his thought on such subjects as the characteristics of solid bodies, accelerated motion, and the parabolic path of projectiles. In 1637, shortly after discovering the moon's libration, Galileo lost the sight of his right eye. A year later he was totally blind. He continued with the help of his disciples, E. Torricelli and V. Viviani (1622–1703), dictating addenda to his Discourses and experimenting. He was buried in the Church of S. Croce in Florence. Only in 1737 was permission finally obtained to erect a monument over his tomb.

Contributions to Scientific Thought. Galileo made many significant contributions to the progress of human thought. In astronomy his contributions were observational rather than theoretical. He made numerous discoveries, but was not a speculative astronomer, as was Kepler. Galileo used his discoveries to argue effectively against some Aristotelian and Ptolemaic doctrines. He showed that it was unnecessary to have one system of mechanics in celestial physics and another in terrestrial physics, and he definitely brought out the inadequacies of the Ptolemaic system. In addition, Galileo deserves to be considered one of the founders of the new mechanics. Some of his criticisms of Aristotelian mechanics had been anticipated by john philoponus and john buridan, but these men made corrections within the framework of Aristotelian qualitative analysis, whereas Galileo, concentrating on the measure of motion, changed the emphasis from explaining why a body moves to why it ceases to move, Galileo formulated a rough approximation of the law of inertia that was later perfected by Sir Isaac Newton.

One of Galileo's most significant contributions to modern science was in the area of methodology. It would be an exaggeration to say that he alone founded a new method or that only he recognized the necessity of experimentation, but he did combine elements from the past and prepare the way for the future. Galileo's approach to a scientific problem was to begin by abstracting from concrete factors that were not easily controllable, for example, resistance. He could then formulate simple laws based on idealized description. These would subsequently be applied, making allowance for concrete, physical circumstances. In his method, the use of experiment was primarily to illustrate insights that were the result of prior scientific theorizing; secondarily, it provided the basis for theories where there were no original, pre-experimental insights.

Galileo's true originality, however, lay in his insistence that the book of nature is written only in mathematical characters such that the inner workings of nature can only be expressed mathematically. As far as Galileo was concerned, whatever could not be caught in mathematical abstraction, such as secondary sense qualities, essences, and causes, were either subjective or did not exist. Such a view denied the need for a natural philosophy in the traditional sense. Newton, who fully appreciated the mathematical approach to reality, did not accept Galileo's mathematical "realism" but allowed for the validity of the traditional qualitative, philosophical inquiry. Galileo, then, represents in many ways the culmination of certain scientific trends that existed before him, especially at Paris, Oxford, and Padua, and part of a new beginning for science that led to Newton and beyond.

Bibliography: Le opere di Galileo Galilei, ed. a. favaro, 20v. (Florence 1929–39), contains Galileo's works and minor writings as well as many documents pertaining to his conflict with the theologians. Galileo's most important works are available in English: Dialogue concerning the Two Chief World Systems, tr. s. drake (Berkeley 1953); Dialogues concerning Two New Sciences, tr. h. crew and a. de salvio (New York 1914; pa. repr. 1952); Discoveries and Opinions of Galileo, ed. and tr. s. drake (New York 1957), contains translations of the Sidereus Nuncius, Letters on Sunspots, Letter to the Grand Duchess Christina and most of the Assayer. There is an enormous amount of secondary source material on Galileo. The philosophical background for his work is well handled in e. a. burtt, The Metaphysical Foundations of Modern Physical Science (rev. ed. Garden City 1932; repr. Anchor Bks 1954) and j. a. weisheipl, The Development of Physical Theory in the Middle Ages (New York 1960). Galileo's scientific work is analyzed in a. koyrÉ, Études Galiléenes (Paris 1939) and clearly explained by i. b. cohen, The Birth of a New Physics (Garden City 1960). The most important books recounting the events of the condemnation include j. j. langford, Galileo, the Church and Science (New York 1966), f. s. taylor, Galileo and the Freedom of Thought (London 1938), and g. de santillana, The Crime of Galileo (Chicago 1955), which is a very readable though not altogether fair account of the famous conflict. r. j. blackwell, Science, Religion and Authority: Lessons from the Galileo Affair (Milwaukee 1998); Galileo, Bellarmine, and the Bible: Including a Translation of Foscarini's Letter on the Motion of the Earth (Notre Dame, Ind.1991). t. campanella, A Defense of Galileo, the Mathematician from Florence: Which Is an Inquiry as to Whether the Philosophical View Advocated by Galileo Is in Agreement with, or Is Opposed to, the Sacred Scriptures, tr. with intro. r. j. blackwell (Notre Dame 1994). w. a. wallace, Galileo's Logic of Discovery and Proof: The Background, Content, and Use of His Appropriated Treatises on Aristotle's Posterior Analytics (Dordrecht; Boston 1992); Galileo and His Sources: The Heritage of the Collegio Romano in Galileo's Science (Princeton, N.J. 1984); w. a. wallace, ed., Reinterpreting Galileo (Washington, D.C. 1986). m. a. finocchiaro, ed. and trans., The Galileo Affair: A Documentary History (Berkeley 1989). e. mcmullin, ed., Galileo, Man of Science (Princeton Junction, N.J. 1988). p. cardinal poupard, ed., Galileo Galilei: Toward a Resolution of 350 Years of Debate, 1633-1983, epilogue john paul ii, trans. i. campbell (Pittsburgh 1987). s. drake, Galileo at Work: His Scientific Biography (Chicago 1981, c1978). d. shapere, Galileo: A Philosophical Study (Chicago 1974).

[j. j. langford]