A recent article in Philosophy of Science by Andrew Lugg (1985), revives interest once again in Johannes Kepler’s so-called “discovery” of the laws of planetary motion. Typically, as if by some recurring philosophical instinct, it focuses on Kepler’s finally settling on the ellipse for planetary orbits--the first of his three laws. There is a fascination with the limiting shape of what is still taken to be the scope of the Sun’s sovereign domain, rather than with the second, or, even more rarely, the third law. Ever since the famous debate between John Stuart Mill and William Whewell, philosophers and historians have been drawn to this notable advance in early modern science--in what Kepler himself calls his “war on Mars” (the planet itself named after the “god” of war).