Galileo’s trial in 1633 before the Roman Inquisition is one of the most frequently mentioned topics in the history of science. Galileo’s encounter with the Catholic Church was not only a major turning point in the history of western culture; it is the paradigm case of the clash between the institutional authority of religion and the authority of scientific reason, a clash that has helped to define the modern era.

Blackwell’s new contribution to the Galileo affair concerns the official theological position against Galileo. The centerpiece of his project is the treatise entitled Tractatus syllepticus, written by Melchior Inchofer, S.J., whose judgment of the orthodoxy of Galileo’s Dialogue had been requested earlier by the Holy Office and was then incorporated into the proceedings of the trial. At the time, Inchofer’s judgment against Galileo’s book was both detailed and harsh. That judgment formed the basis for Inchofer’s subsequent Tractatus, the first English translation of which is included in this volume. Inchofer’s text provides a new and fascinating way of looking at the defense of the guilty verdict. Blackwell’s analysis of this material greatly enriches our knowledge of Galileo and his trial.

Both legal and theological behind-the-scenes aspects of Galileo’s trial are discussed. Because of a weak legal case, a plea bargain was arranged, extrajudicially, then sabotaged in the Holy Office before the final decision of the case. Through his close scrutiny of the specifics of the trial, Blackwell renders a picture that is more complex, and ominous, than the usual portrayal of the trial.