as Galileo did, that a rotating, revolving Earth made for a more rational universe – that asking the innumerable, enormous stars to fly daily around the Earth at fantastic speeds was like climbing to a cupola to view the countryside and then expecting the landscape to revolve around one’s head. Such reasoning, however, said nothing about the way God had actually constructed the firmament.
Even Galileo’s discovery of the phases of Venus, which he had dealt as a death blow to the Ptolemaic system, did not constitute proof of the Copernican. The planetary system of Danish astronomer Tycho Brahe could take Venus by the horns and still enable the Earth to remain immobile. According to the Tychonic order, the five planets orbited the Sun, while the Sun – surrounded by Mercury, Venus, Mars, Jupiter and Saturn – circled the stationary Earth. Although Tycho had based this theory on decades of careful observations, Galileo dismissed his plan as even sillier than the Ptolemaic. Since he could not prove the Copernican system by telescope alone, however, he turned to the tides to cement the case. He required the seas to rise to the rescue, not merely of Copernicus’s reputation or his own, but to preserve Italy’s future scientific pre-eminence and – most important – to protect the honour of the Catholic faith. For if the Holy Fathers banned Copernicus, as rumour predicted they might do at any moment, then the Church would endure ridicule when a new generation of telescopes, probably manned by infidels, eventually uncovered the conclusive evidence for the Sun-centred system.
The waters of the world occupy a moving vessel, Galileo wrote in his ‘Treatise on the Tides’. This vast container of water turns on its axis once every day and travels around the Sun once a year. The combination of the two Copernican motions accounts for all tides. The timing and magnitude of specific tides in different locations, however, depend also on many contingent factors, including the extent of each body of water (this was why ponds and small lakes lacked tides), its depth (and consequently the volume of fluid involved), the way it orients itself on the globe (since an east-west waterway like the Mediterranean experienced more dramatic tides than the nearly north-south Red Sea), and its nearness to other bodies of water (which proximity could cause powerful currents and floods, as at the Straits of Magellan where the Atlantic met the Pacific Ocean). Galileo, who never once left Italy, had gathered reports from far and wide to flesh out his explication.
‘To hold fast the basin of the Mediterranean and to make the water contained within it behave as it does surpasses my imagination,’ Galileo declared, ‘and perhaps that of anyone else who enters more than superficially into these reflections.’
But here, again, the fact that Galileo could not account for the tides without moving the Earth did not prove that the Earth moved. What’s more, his theory of the tides, though carefully crafted and eminently reasonable, was wrong. Throughout his life he ignored the true cause of the tides, which rise and fall by the pull of the Moon, because he failed to see how a body so far away could exert so much power. To him, the concept of ‘lunar influence’ smacked of occultism and astrology. Galileo occupied a universe without gravity.* As for the force that made moons orbit planets and planets orbit the Sun in Galileo’s cosmology, they might as well have been pushed around by angels.
Kepler, Galileo’s German contemporary, made the Moon the centrepiece of his own tidal theory. Kepler’s thinking, however, riddled with mystical allusions to the Moon’s affinity for water, alienated Galileo’s strictly logical mind. (Kepler had even posited intelligent beings on the Moon, as builders of the features observed from Earth.) What’s more, Galileo may have had some trepidation about relying on the testimony of a German Protestant.
Galileo presented his manuscript treatise on the tides to one of the newest cardinals in Rome, twenty-two-year-old Alessandro Orsini, a cousin of Grand Duke Cosimo. Galileo wanted Cardinal Orsini to pass the paper on to the current pope, Paul V, whose endorsement might help settle the issue. The young cardinal dutifully delivered the paper, but the sixty-three-year-old pontiff refused to read it. Instead, His Holiness pushed the moment to its crisis by convening expert consultors to decide once and for all whether the Copernican doctrine could be condemned as heretical.
The pope summoned his theological adviser, Roberto Cardinal Bellarmino, the pre-eminent Jesuit intellectual who had served as inquisitor in the trial of Giordano Bruno. Cardinal Bellarmino, the ‘hammer of the heretics’, had once confided to Prince Cesi of the Lyncean Academy that he personally considered the opinion of Copernicus heretical, and the motion of the Earth contrary to the Bible. (This admission prompted Cesi to wonder whether De revolutionibus would ever have been published had Copernicus lived after the Council of Trent, instead of before it.)
Bellarmino knew Galileo from meetings at social occasions over a period of some fifteen years, had viewed Jupiter’s moons through his telescope in 1611, and highly respected his achievements, which he could appreciate more than most, having studied astronomy himself at Florence. The only fault Cardinal Bellarmino found with Galileo was the man’s insistence on treating the Copernican model as a real-life scenario instead of a hypothesis. After all, there was no proof. The cardinal further opined that Galileo should stick to astronomy in public and not try to tell anyone how to interpret the Bible.
The Council of Trent, Cardinal Bellarmino took pains to point out, prohibited the interpretation of Scripture contrary to the common agreement of the Holy Fathers – all of whom, along with many modern commentators, understood the Bible to state clearly that the Sun travelled around the Earth. ‘The words “the Sun also riseth and the Sun goeth down, and hasteth to his place where he arose, etc.” were those of Solomon,’ Cardinal Bellarmino wrote,
who not only spoke by divine inspiration but was a man wise above all others and most learned in human sciences and in the knowledge of all created things, and his wisdom was from God. Thus it is not likely that he would affirm something which was contrary to a truth either already demonstrated, or likely to be demonstrated. And if you tell me that Solomon spoke only according to the appearances, and that it seems to us that the Sun goes around when actually it is the Earth which moves, as it seems to one on a ship that the shore moves away from the ship, I shall answer that though it may appear to a voyager as if the shore were receding from the vessel on which he stands rather than the vessel from the shore, yet he knows this to be an illusion and is able to correct it because he sees clearly that it is the ship and not the shore that is in movement. But as to the Sun and the Earth a wise man has no need to correct his judgment, for his experience tells him plainly that the Earth is standing still and that his eyes are not deceived when they report that the Sun, Moon and stars are in motion.
Galileo was still in Rome in February 1616 when the inevitable happened. At the request of Pope Paul V, who devoted his papacy to promulgating Council of Trent reforms, the cardinals of the Holy Office framed the Copernican argument as two propositions to be voted on by a panel of eleven theologians:
1 The Sun is the centre of the world, and consequently is immobile of local motion.
2 The Earth is not the centre of the world, nor is it immobile, but it moves as a whole and also with a diurnal motion.
The unanimous verdict of the panel pronounced the first idea not only ‘formally heretical’, in that it directly contradicted Holy Scripture, but also ‘foolish and absurd’ in philosophy. The theologians found the second concept equally shoddy philosophically, and ‘erroneous in faith’, meaning that although it did not gainsay the Bible in so many words, it nevertheless undermined a matter of faith.
The consultors cast their ballots on 23 February and reported their conclusions to the Holy Office of the Inquisition the following day. Although no public announcement came out of official chambers, Galileo got a special summons and personal notification of the outcome almost immediately.
On 26 February, two officers of the Inquisition came to collect him from the Tuscan embassy. They escorted him to the palace of Lord Cardinal Bellarmino, who personally
