, Volume 83, Issue 2, pp 317–323 | Cite as

Copernicus, the orbs, and the equant

  • Peter Barker


I argue that Copernicus accepted the reality of celestial spheres on the grounds that the equant problem is unintelligible except as a problem about real spheres. The same considerations point to a number of generally unnoticed liabilities of Copernican astronomy, especially gaps between the spheres, and the failure of some spheres to obey the principle that their natural motion is to rotate. These difficulties may be additional reasons for Copernicus's reluctance to publish, and also stand in the way of strict realism as applied to De Revolutionibus, although a realistic astronomy may be envisioned as a goal for Copernicus's research program.


Research Program Additional Reason Equant Problem Natural Motion Real Sphere 
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Copyright information

© Kluwer Academic Publishers 1990

Authors and Affiliations

  • Peter Barker
    • 1
  1. 1.Center for the Study of Science in SocietyVirginia Polytechnic Institute and State UniversityBlacksburgUSA

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