Hard as it is to believe, what is possibly Galileo's most important Latin manuscript was not transcribed for the National Edition of his works and so has remained hidden from scholars for centuries. In this volume William A. Wallace translates the logical treatises contained in that manuscript and makes them intelligible to the modern reader. He prefaces his translation with a lengthy introduction describing the contents of the manuscript, the sources from which it derives, its dating, and how it relates to Galileo's other Pisan writings. The translation is accompanied by extensive notes and commentary; these explain the text and tie it to the fuller exposition of Galileo's logical methodology in the author's companion volume, Galileo's Logic of Discovery and Proof. The result is a research tool that is indispensable for anyone intent on understanding Galileo's logic as described in that volume and the documentary evidence on which it is based.

This volume is presented as a companion study to my translation of Galileo's MS 27, Galileo's Logical Treatises, which contains Galileo's appropriated questions on Aristotle's Posterior Analytics - a work only recently transcribed from the Latin autograph. Its purpose is to acquaint an English-reading audience with the teaching in those treatises. This is basically a sixteenth-century logic of discovery and of proof about which little is known in the present day, yet one that arguably guided the most significant research program of the seventeenth century. Despite its historical and systematic importance, the teaching is difficult to explain to the modern reader. Part of the problem stems from the fragmentary nature of the manuscript in which it is preserved, part from the contents of the teaching itself, which requires a considerable propadeutic for its comprehension. A word of explanation is thus required to set out the structure of the volume and to detail the editorial decisions that underlie its organization. Two major manuscript studies have advanced the cause of scholarship on Galileo within the past two decades. The first relates to Galileo's experimental activity at Padua prior to his discoveries with the telescope that led to the publication of his Sidereus nuncius in 1610. Much of this activity has been uncovered by Stillman Drake in analyses of manuscript fragments associated with the composition of Galileo's Two New Sciences, fragments now bound in a codex identified as MS 72 in the collection of Galileiana at the Biblioteca Nazionale Centrale in Florence.

Galileo’s Dialogue Concerning the Two Chief World Systems, published in Florence in 1632, was the most proximate cause of his being brought to trial before the Inquisition. Using the dialogue form, a genre common in classical philosophical works, Galileo masterfully demonstrates the truth of the Copernican system over the Ptolemaic one, proving, for the first time, that the earth revolves around the sun. Its influence is incalculable. The Dialogue is not only one of the most important scientific treatises ever written, but a work of supreme clarity and accessibility, remaining as readable now as when it was first published. This edition uses the definitive text established by the University of California Press, in Stillman Drake’s translation, and includes a Foreword by Albert Einstein and a new Introduction by J. L. Heilbron.

For more than 30 years, historians have rejected what they call the ‘warfare thesis’ – the idea that there is an inevitable conflict between religion and science – insisting that scientists and believers can live in harmony. This book disagrees. Taking as its starting point the most famous of all such conflicts, the Galileo affair, it argues that religious and scientific communities exhibit very different attitudes to knowledge. Scripturally based religions not only claim a source of knowledge distinct from human reason. They are also bound by tradition, insist upon the certainty of their beliefs, and are resistant to radical criticism in ways in which the sciences are not. If traditionally minded believers perceive a clash between what their faith tells them and the findings of modern science, they may well do what the Church authorities did in Galileo’s time. They may attempt to close down the science, insisting that the authority of God’s word trumps that of any ‘merely human’ knowledge. Those of us who value science must take care to ensure this does not happen.

The unifying theme in this second volume of essays by William A. Wallace to be published in the Variorum series is signaled in the title of the opening paper: 'Domingo de Soto and the Iberian roots of Galileo's science'. The seven essays in the first part provide textual studies of Soto's early formulations of the laws of falling bodies, the context in which they were developed in the 16th century, and the ways in which they were transmitted in Spain and Portugal to the early 17th century, mainly by Jesuit scholars. The following essays focus on the young Galileo and his work at Pisa and Padua, leading to his discovery of the law of uniform acceleration in free fall. Textual evidence is presented for an indirect influence of Soto's work on Galileo, mediated by Jesuits who were teaching at Padua in the first decade of the 17th century.