Many literary critics seem to think that an hypothesis about obscure and remote questions of history can be refuted by a simple demand for the production of more evidence than in fact exists. The demand is as easy to make as it is impossible to satisfy. But the true test of an hypothesis, if it cannot be shown to con?ict with known truths, is the number of facts that it correlates and explains. Francis M. Cornford [1914] 1934, 220. It was in the autumn of 1997 that the research project leading to this publication began. One of us [GH], while a visiting fellow at the Center for Philosophy of Science (University of Pittsburgh), gave a talk entitled, "Proportions and Identity: The Aesthetic Aspect of Symmetry". The presentation focused on a confusion s- rounding the concept of symmetry: it exhibits unity, yet it is often claimed to reveal a form of beauty, namely, harmony, which requires a variety of elements. In the audience was the co-author of this book [BRG] who responded with enthusiasm, seeking to extend the discussion of this issue to historical sources in earlier periods. A preliminary search of the literature persuaded us that the history of symmetry was rich in possibilities for new insights into the making of concepts. John Roche's brief essay (1987), in which he sketched the broad outlines of the history of this concept, was particularly helpful, and led us to conclude that the subject was worthy of monographic treatment.

This monograph examines James Clerk Maxwell's contributions to electromagnetism to gain insight into the practice of science by focusing on scientific methodology as applied by scientists. First and foremost, this study is concerned with practices that are reflected in scientific texts and the ways scientists frame their research. The book is therefore about means and not ends.

This monograph examines James Clerk Maxwell's contributions to electromagnetism to gain insight into the practice of science by focusing on scientific methodology as applied by scientists. First and foremost, this study is concerned with practices that are reflected in scientific texts and the ways scientists frame their research. The book is therefore about means and not ends.

It would seem that S. Munk was the first modern scholar to draw attention to the significance of Levi ben Gerson's Astronomy, surely the most original work on astronomy written in Hebrew in the Middle Ages. Munk (1859, p. 500) called for a specialist to undertake a serious study of this work, but there was little response to his plea in the succeeding century. Indeed, this is the first edition of the Hebrew text of any part of Levi's Astronomy but for the table of contents (Renan, 1893, pp. 624-32), and the poems celebrating the invention of the Jacob Staff that appear in chapter 9 (Carlebach, 191Oa, pp. 152-53). The text of Levi's Astronomy is written in a ponderous Hebrew style but the content sparkles with originality. The Ptolemaic tradition is subjected to a profound critique based on the idea that the planetary models must conform both to Levi's own observations as well as those of the ancients, and the claim that astronomical theory must be philosophically sound. The enduring vigor of the Ptolemaic tradition has been characterized by O. Neugebauer as fol lows: "There is no better way to convince oneself of the inner coherence of ancient and medieval astronomy than to place side by side the Almagest, al BaWini's Opus astronomicum and Copernicus's De Revolutionibus. Chapter by chapter, theorem by theorem, table by table, these works run parallel" (1957, pp. 205-6)."

Many literary critics seem to think that an hypothesis about obscure and remote questions of history can be refuted by a simple demand for the production of more evidence than in fact exists. The demand is as easy to make as it is impossible to satisfy. But the true test of an hypothesis, if it cannot be shown to con?ict with known truths, is the number of facts that it correlates and explains. Francis M. Cornford [1914] 1934, 220. It was in the autumn of 1997 that the research project leading to this publication began. One of us [GH], while a visiting fellow at the Center for Philosophy of Science (University of Pittsburgh), gave a talk entitled, "Proportions and Identity: The Aesthetic Aspect of Symmetry". The presentation focused on a confusion s- rounding the concept of symmetry: it exhibits unity, yet it is often claimed to reveal a form of beauty, namely, harmony, which requires a variety of elements. In the audience was the co-author of this book [BRG] who responded with enthusiasm, seeking to extend the discussion of this issue to historical sources in earlier periods. A preliminary search of the literature persuaded us that the history of symmetry was rich in possibilities for new insights into the making of concepts. John Roche's brief essay (1987), in which he sketched the broad outlines of the history of this concept, was particularly helpful, and led us to conclude that the subject was worthy of monographic treatment.

This book provides a unique contribution to philosophy of science from the perspective of the practice of science. It focuses on processes that generate scientific knowledge and seeks general and universal features that characterize scientific practice; features that are inherent to the practice of science. Science is an activity, and the scientist is an agent who pursues some practice, which in one way or another engages evidence. In science, claims to knowledge are typically supported by argument that engages evidence at some point in explanation, in prediction, or indeed in any mode of presenting data and its interpretation. Thus, the practice of science includes at least three elements so that an argument can be formulated: presuppositions, modes of inference, and consequences that relate to evidence. The authors discuss in detail eight cases in chronological order with which they illustrate how commitment, methodology, and technique come into play in the practice of an individual physicist or a group of researchers in the physical sciences. Each case highlights aspects of the roles these categories play in scientific practice, where the goal is to generate and extend scientific knowledge.