Galileo was silenced for a while, but it was impossible for him to be mute for ever. Under a new Pope (Urban VIII) he looked for greater liberty, and there were many in the Papal circle who were well disposed to him. He hoped to avoid difficulties by the device of placing the arguments for the old and the new theories side by side, and pretending not to judge between them. He wrote a treatise on the two systems (the Ptolemaic and the Copernican) in the form
[89] of Dialogues, of which the preface declares that the purpose is to explain the pros and cons of the two views. But the spirit of the work is Copernican. He received permission, quite definite as he thought, from Father Riccardi (master of the Sacred Palace) to print it, and it appeared in 1632. The Pope however disapproved of it, the book was examined by a commission, and Galileo was summoned before the Inquisition. He was old and ill, and the humiliations which he had to endure are a painful story. He would probably have been more severely treated, if one of the members of the tribunal had not been a man of scientific training (Macolano, a Dominican), who was able to appreciate his ability. Under examination, Galileo denied that he had upheld the motion of the earth in the Dialogues, and asserted that he had shown the reasons of Copernicus to be inconclusive. This defence was in accordance with the statement in his preface, but contradicted his deepest conviction. In struggling with such a tribunal, it was the only line which a man who was not a hero could take. At a later session, he forced himself ignominiously to confess that some of the arguments on the Copernican side had been put too strongly and to declare himself ready to confute the
[90] theory. In the final examination, he was threatened with torture. He said that before the decree of 1616 he had held the truth of the Copernican system to be arguable, but since then he had held the Ptolemaic to be true. Next day, he publicly abjured the scientific truth which he had demonstrated. He was allowed to retire to the country, on condition that he saw no one. In the last months of his life he wrote to a friend to this effect: The falsity of the Copernican system cannot be doubted, especially by us Catholics. It is refuted by the irrefragable authority of Scripture. The conjectures of Copernicus and his disciples were all disposed of by the one solid argument: Gods omnipotence can operate in infinitely various ways. If something appears to our observation to happen in one particular way, we must not curtail Gods arm, and sustain a thing in which we may be deceived. The irony is evident.