Copernicus had a one-track mind; he never flew off at a tangent; even his cheatings were heavy-handed. Tycho was a giant as an observer, but nothing else. His leanings toward alchemy and astrology never fused, as in Kepler, with his science. The measure of Kepler’s genius is the intensity of his contradictions, and the use he made of them. We saw him plod, with infinite patience, along dreary stretches of trial-and-error procedure, then suddenly become airborne when a lucky guess or hazard presented him with an opportunity.
