Copernicus, Kepler, and Galileo

A review of the book Sleepwalkers that discusses the history of astronomy with a focus on Copernicus, Kepler and Galileo.

Some interesting bits:

On Galileo and the Church:

Koestler attributes Galileo’s persecution by the Church not to an inevitable clash between science and religion, but rather to Galileo’s own bullheadedness in attempting to force a theological surrender without having much evidence, and his tendency to insult and alienate important people. [...] Koestler argues that the Church had a lot of respect for scientists, and in general was willing to reinterpret doctrine based on compelling scientific arguments, but that Galileo’s actions made opposition to heliocentrism last much longer than it otherwise would have.

Why it took so long to figure out the laws guiding planetary motion:

In short, the answer seems to be Plato and Aristotle: as Koestler portrays them, “two frightened men standing in [Plato’s] Cave, facing the wall, chained to their places in a catastrophic age, turning their back on the flame of Greece’s heroic era, and throwing grotesque shadows which are to haunt mankind for a thousand years and more.” This is unduly harsh - and yet how damaging the blind adherence to their ideas which lasted, with few exceptions, until the 16th century! Two of Plato’s most influential tenets: that true knowledge cannot be obtained by the study of nature, but must be gained by consideration of the perfect world of Forms and Ideas; and that, for metaphysical reasons, all celestial motion must be in perfect circles at uniform speed. Aristotle then introduced the distinction between the imperfect and changeable earth, and the eternal and unchanging cosmos; also, that each movement was due to an object’s telos, or purpose. Lastly, God was placed on the outermost sphere, furthest away from the Earth. Their combined influence had astronomers thinking in circles for almost 2000 years!