  In 1651 the Italian astronomer Giovanni Battista Riccioli published within
his Almagestum Novum, a massive 1500 page treatise on astronomy, a discussion
of 126 arguments for and against the Copernican hypothesis (49 for, 77
against). A synopsis of each argument is presented here, with discussion and
analysis. Seen through Riccioli's 126 arguments, the debate over the Copernican
hypothesis appears dynamic and indeed similar to more modern scientific
debates. Both sides present good arguments as point and counter-point.
Religious arguments play a minor role in the debate; careful, reproducible
experiments a major role. To Riccioli, the anti-Copernican arguments carry the
greater weight, on the basis of a few key arguments against which the
Copernicans have no good response. These include arguments based on telescopic
observations of stars, and on the apparent absence of what today would be
called "Coriolis Effect" phenomena; both have been overlooked by the historical
record (which paints a picture of the 126 arguments that little resembles
them). Given the available scientific knowledge in 1651, a geo-heliocentric
hypothesis clearly had real strength, but Riccioli presents it as merely the
"least absurd" available model - perhaps comparable to the Standard Model in
particle physics today - and not as a fully coherent theory. Riccioli's work
sheds light on a fascinating piece of the history of astronomy, and highlights
the competence of scientists of his time.
