Geo-heliocentric models and the Society of Jesus: from Clavius's resistance to Dechales's Mathesis Regia.

In 1588 Tycho Brahe proposed a new cosmological system keeping a motionless Earth at the centre of the world. In the first half of the following century the reception of Tycho's model within the Society of Jesus was characterized by a strong resistance at the beginning, followed by a long and winding path, and then a good fortune, whereas heliocentric models were increasingly investigated in European observatories. In 1651 a Jesuit astronomer, Giovan Battista Riccioli, published the Almagestum novum, an encyclopaedic synthesis of astronomical knowledge where the Earth's motions or rest were extensively discussed in order to prove the Earth's immobility. However, through the period 1650-1687 the Almagestum novum did not entirely fulfil its aims, rather seeming like the dying swan's song of Tychonic or semi-Tychonic models. Contemporary scholars appreciated the encyclopaedic effort by Riccioli, but many were critical of his proofs. Even influential Jesuit astronomers showed a remarkable interest in the Copernican model, accepting geocentric models only on the basis of Holy Scripture's authority. This conduct and the tacitly allowed circulation in Catholic Europe of openly Copernican books, indicate that Catholic science tolerated heliocentric theory, when presented as a computational device rather than a representation of reality, more frequently than we usually think.