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The Copernican Revolution: Planetary Astronomy in the Development of Western Tho

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Kuhn masterfully depicts the changes which, not only brought about the Copernican Revolution, but also, more abstractly, links them to prevaling modes of western thought as they differ from eastern models of the universe. Kuhn's attempt succeeds at placing the reader on the road to scientific revelation, not only the Copernican Revolution per se, but the political and religious currents which not only resisted it, but made it necessary. His work traces the early work of Greek astronomers and the problems they dealt with in depicting the motions of the planets and the position of the earth in the universe. He moves into Copernicus' work as a quasi-scientific endeavor synthesizing neo-Platonic forms and astute astronomical observation. This he elucidates fully, by infusing the work of other astronomers, namely Kepler,Galileo and Brahe. On a whole the book is a good example of how attitudes are changed by a revolutionary figure and a radical departure from established "paradigms" of science. Moreover, Kuhn shows us the genre of scientific history which is so important to understanding these types of issues. His book is easy to understand given cursory astronomical background and will prove invaluable in understanding not only the thought of Copernicus himself, but more precisely, the real revolution which it began. It is a must for all history students and would provide interesting topical information for science majors and star-gazers alike. You should come away with the idea that "astronomers" of the past were not as scientific as we would expect them to be, and furthermore, revolutions do not take place in a vacuum but rather are dependent on an atmosphere and necessity for acceptance.

This book, written before his Structures, is condensed, well written and, for me at any rate, highly entertaining. No one with a casual understanding of the history of astronomy can read this and not be surprised. Of special interest is the illumination of the fact that at the time Copernicus offered his Helio-centric cosmology there was no good, scientific reason for accepting it - it being a geometric inversion of the Ptolemaic system and thus inheriting exactly all of the Ptolemaic deficiencies. Kuhn explores the reason for the gradual shift to Copernicanism and the effects a moving earth had on other sciences.

This book is an excellent and entertaining book for a scientific reader and/or for a general reader who doesn't mind being challenged a bit by logical arguments. Don't let this discourage you, though, since the logical arguments are not too difficult and really need to be discussed for completeness sake. The historical background adds to the book in a way comparable to Carl Sagan's 'COSMOS' series or to 'The Mechanical Universe' series. This book should be required reading for all enlightened westerners. It's THAT good.

I just want to focus on one aspect of this book. The first chapter and the appendix forms a very nice introduction to basic astronomy. If you want to read a book like "The Sun in the Church, Cathedrals as Solar Observatories" by Heilbron, but get shell shocked by the astronomy, then Kuhn's book is a good place to start. It's not easy reading, but Kuhn has a lot of very good pictures.

It is a pity that the Amazon rating system is limited to only 5-stars. This book is, in my opinion, worth many more. I must admit that I hesitated getting this book for many years as I was misled by the sub-title "Planetary Astronomy in the Development of Western Thought". I believed this to be a thick and imponderable philosophical tome - it is not. The book is clearly written, and does not require that the reader have a mathematical, philosophical or astronomical background. The book describes the paradigm shift from an earth-centered universe to a sun-centered one. It thus begins with the astronomical beliefs of the ancient Greeks and shows the evolution of astronomy from this to that of Copernicus and then to Newton's explanation using his equations of gravity.

I learned a lot from this book. For instance,
1. I learned a bit about solar and celestial navigation.
2. I never even realized that the seasons are of unequal length, now I do and I understand why.
3. I now have a reasonable idea of the complexity of the Ptolemaic (earth-center) view of the cosmos and why it was believed for 2000 years. Kuhn does a great job of explaining and describing the essence of this very complex system.
4. I now understand some of the influences that led Copernicus to believe that the Ptolemaic paradigm needed to be replaced. The reasons for this shift were many and complex, but are clearly stated.
5. I always thought that the system developed by Copernicus was what we believe today, but now I realize that it was much more complex, but that while it was as complex as that of Ptolemy it was not more accurate in its predictions. I also see why some of the incorrect assumptions made by Copernicus led to this complexity and lack of accuracy.
6. I clearly see why in spite of its complexity and lack of increased accuracy the Copernican paradigm gradually replaced the Ptolemaic paradigm, but not without overcoming a considerable amount of resistance.
7. I understand the importance of the contributions of Tycho Brahe and Johannes Kepler to the ultimate dominance of the Copernican system.
8. I learned how Johannes Kepler, Rene Descartes and Robert Hooke influenced the work of Isaac Newton and that Newton's laws of gravity were not a unique creation of his alone, although its complete mathematical formulation certainly was.

These ideas in this book are presented in a very clear and very accessible manner. I now have to add this book to my short list of those that I think anyone who considers himself/herself well educated should be acquainted with.

Kuhn's The Copernican Revolution was written as a text for an undergraduate course in the intellectual history of science. As such, its approach is focused and temporally expansive. The drawback of such an approach is the deficit of analysis in key areas. The analysis of the Church's role in science during the late middle ages and Renaissance was rather one-dimensional, but this obviously is not Kuhn's focus. Instead, he would like the reader to realize that any set of data can be modeled to an infinite number of paradigms (in anticipation of Structure of Scientific Revolutions). The heliocentric argument solved some qualitative problems but was largely Ptolemaic in articulation. Its aesthetic and geometric harmonies were extracted by astronomers who could could apply a mathematical rigor to it, in a post-Ptolemaic tradition (Kepler and Newton).

Kuhn challenges the reader's imagination to decipher the heavenly phenomena in the same way Ptolemy might have, without being hampered by the technical minutia of astronomy. He writes so lucidly as to pick the reader up and drop him or her under the ancient sky, and to follow a long, through time. Paramount to Kuhn is the practical importance of astronomical data and the logic of its categorization.

Perhaps the most persuasive analysis that Kuhn endeavors is that of the progression of the Renaissance neo-Platonics: Brahe, Galilei, Kepler, Descartes, and the mutation of the Copernican system into Newtonian synthesis. In one sense, his analysis is very non-Kuhnian as it can't point to a singular moment, and involves more of a patchwork of adopting new features (that is until Newton).

A concise introduction to the evolution of astronomical thought from antiquity to newton and a compelling classic.

Unlike 'the Structure of Scientific Revolutions', this book is well-written and informative, if you want to know about the development of ancient astronomy. Belongs with serious, entertaining and informative books on the history of science like those by Hoyle (who explains what Copernicus really did) and Barbour (who pointed me to Hoyle in the first place).

This book was interesting, but is not for the casual reader. Kuhn's condensed summary of pre-Copernican cosmology is still too technical for many readers; I found some passages difficult to slog through myself. Many of his insights and connections were wonderfully interesting, but I was a little disappointed that after the long, technical build-up there wasn't a little "more" there. Usually a book that leaves you wanting more is a sign of a satisfying read, but although I enjoyed this book and found it enlightening in many places, in this case my wanting "more" was because I wasn't quite satisfied by it.

This is a great overview of the development of the Copernican system. The main text is very clear and readable and the "technical appendix" has good expositions of key mathematical arguments. Nevertheless, I think Kuhn's interpretation of "the Copernican revolution" has some shortcomings.

Kuhn wishes the Copernican revolution to conform to his idea of a revolution brought on by a crisis (e.g. p. 139). To prove this he relies entirely on Copernicus' preface, which he elsewhere calls "one of the classic descriptions of a crisis state" (Structure of Scientific Revolutions, p. 69).

Kuhn's interpretation rests on the following two points:

(i) Determination of the length of the year for calendar purposes was Copernicus' "first" motivation and "heads his list" of motives: "When Copernicus listed the aspects of contemporary astronomy that had led him to consider his radical theory, he began, 'For, first, the mathematicians are so unsure of the movements of the Sun and the Moon that they cannot even explain or observe the constant length of the seasonal year.'" (p. 125) "In Copernicus' day an adequate account of precession was the principal prerequisite for the most pressing problem of practical astronomy, the reform of the Julian calendar ... and it is this remark which heads his list of motives for innovation." (pp. 270--271)

(ii) Copernicus' "monster rather than a man" metaphor expresses a general dissatisfaction with the state of Ptolemaic astronomy. (pp. 139--141)

But (i) is an underhand trick for two reasons. Copernicus' preface is addressed to the Pope and he is clearly interested in emphasising that "my labors contribute somewhat even to the Commonwealth of the Church, of which your Holiness is now Prince," mentioning specifically how the calendar issue was a concern for Leo X, for example. Perhaps this is why he put the calendar first in his preface. Furthermore, when Copernicus says "first...", he does not mean "first" as in "most important," for he continues with a "second" and then reaches "the chief point of all." This chief point of all is the fact that the Copernican model enables the determination of the planetary distances. (A geocentric model cannot give such information because we could scale the orbit of Saturn, say, to make it twice as big and it would still look exactly the same seen from earth. But in a heliocentric model the distances are determined because if we scaled the orbit of Saturn then it would look the same seen from the sun but different seen from earth. So with the earth in the center we cannot determine planetary distances because we are at the center of scaling, but with the sun in the center we would notice scaling and thus the planetary distances are locked.)

Copernicus' "chief point of all" is the basis for a correct reading of the "monster rather than a man" metaphor, thus refuting (ii). As Copernicus puts it, the heliocentric system "binds together so closely the order and the magnitudes of all the planets and of their spheres or orbital circles and the heavens themselves that nothing can be shifted around in any part of them without disrupting the remaining parts and the universe as a whole." For this reason he can claim triumphantly that earlier astronomers "have not been able to discover or to infer the chief point of all, i.e., the form of the world and the certain commensurability of its parts. But they are in exactly the same fix as someone taking from different places hands, feet, head, and the other limbs---shaped very beautifully but not with reference to one body and without correspondence to one another---so that such parts made up a monster rather than a man."

Thus I say: Copernicus was driven not by a crisis of Ptolemaic astronomy but by the beautiful consequences of his theory, such as the determination of the planetary distances and simple explanations of previously unexplained phenomena (e.g., retrograde motion, bounded elongation, etc.).

Kuhn admits that Copernicus' determination of the planetary distances is "crucially important" (p. 180) but dismisses it as the main reason for the acceptance of the theory:

"'Harmony' seems a *strange* basis on which to argue for the earth's motion ... Copernicus' arguments are not pragmatic. They appeal, if at all, not to the utilitarian sense of the practising astronomer but to his aesthetic sense and to that alone. ... New harmonies did not increase accuracy or simplicity. Therefore they could and did appeal primarily to that limited and perhaps *irrational* subgroup of mathematical astronomers whose Neoplatonic ear for mathematical harmonies could not be obstructed by page after page of complex mathematics leading finally to numerical predictions scarcely better than those they had before." (p. 180; emphasis added)

The correct reading---beauty before truth---is staring Kuhn in the face. In fact, Copernicus even spells this out in the very first sentence of his work:

"Among the many and varied literary and artistic studies upon which the natural talents of man are nourished, I think that those above all should be embraced and pursued with the most loving care which have to do with *things that are very beautiful* and very worthy of knowledge." (Copernicus, emphasis added.)

But Kuhn refuses to listen, opting instead to dismiss Copernicus as "strange" and Kepler as "irrational."

This is a great review of astronomy prior to Copernicus and how astronomy then changed. The old Aristotle/Ptolemaic constructions were much more thoughtful than I had learned in secondary school and their predictive power was much better too. So in both a qualitative and quantitative way these theories were hard to dispute even with Copernicus' new sun centered universe, which did not do any better quantitatively. Gradually, as the telescope came into existence (Galileo) so that the observational data pushed the astronomers away from the circles and epicycles to the ellipses, did astronomy advance to predictions quantitatively better. This book shows how that all came to be and how it affected the world outside astronomy. It shows how the old cosmology had come to be adopted as a world view in religion and why they clung to it so. Anyone reading this book will gain a greater respect for what the ancients accomplished and how brilliant they were in building the cosmology that was replaced by Copernicus, Brahe, Kepler, Galileo, and Newton. It also showed how these built on others who are not so well known. It is a fascinating read.