In passing from the first to the second version we added Copernicus as background, and got a clearer result.
If more scientists were like Kepler, science would probably come to a crashing halt. That sort of mystical openness to any and every possible pattern needs to be exercised with some discipline. In this case the discipline was lacking in Kepler, but pro vided on the one hand by Tycho Brahe's excellent data, and on the other by a critical reevaluation by calmer heads, in which most of Kepler's laws were discarded, including his favorite and most Platonic, while three survived and found both a physical and mathematical explanation in subsequent work.
Kepler was sensitive to other significant patterns in nature that were sometimes better evaluated by the common man than by his fellow scientists. He understood that the moon exercised an influence on the tides, as did every sailor, though the great Gali leo referred to the idea as "childish". He also understood that the 6-fold symmetry of the snowflake gave deep information as to the structure of matter, implying an atomic structure organizing itself in regular crystalline patterns.
He did however lack Newton's, or even Galileo's, ability to formulate his hypotheses in testable terms and to subject them to the rigors of mathematical analysis.
There still seems to be a bit of a muddle as far as Jabcobsen's account of one of Kepler's "proofs" is concerned. It is quite clear that Jacobsen is not at all taken in by this proof, and doesn't expect the reader to be either. I would also have to take issue with this idea that mathematics became "the only acceptable means of expressing scientific ideas because of the ease and clarity in which the universality of mathematics allows their communication." This omits the main reason for the influence of Newton's Principia, for example: the fact that Hooke's law of gravitation could be shown to account for all of Kepler's laws on purely mathe matical grounds.
As far as the Osiander preface is concerned, my understanding is that Copernicus was in any case on his deathbed and can hardly have been personally concerned with any concrete consequences of its publication, certainly not for his personal safety, thoug h the issue of the reception of the system is of course another matter. The question arises, what or whom was Osiander trying to protect?
The Jacobsen is very nice, and the Marie Boas Hall I have always liked. It is good to have the Harmony of the World as primary source material. Most of the remainder I am still unfamiliar with, but I see no clear duds in this collection. There is a standard reference for the history of astronomy, Pannekoek, which I have not read.
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