Setting Aside All Authority: Giovanni Battista Riccioli and the Science against Copernicus in the Age of Galileo by Christopher M. Graney

Abstract

Setting Aside All Authority: Giovanni Battista Riccioli and the Science against Copernicus in the Age of Galileo. By Christopher M. Graney. (Notre Dame: University of Notre Dame Press. 2015. Pp. xv, 270. $29.00 paperback. ISBN 978-0-26802988-3.)The Revolution is the transition from the ancient worldview, claiming that the earth stands still at the center of the universe, to the modern worldview asserting that the earth is a planet rotating daily around its own axis and revolving annually around the sun. The transition was a long and difficult process taking about 150 years, roughly from Copernicus's On the Revolutions of the Heavenly Spheres (1543) to Newton's Mathematical Principles of Natural Philosophy (1687). The difficulties stemmed from the fact that there were many strong arguments against the earth's motion: they were not merely biblical and religious, philosophical and epistemological, but also observational, astronomical, and mechanical. For example, if the earth revolved, then we should observe an annual parallax in the apparent position of fixed stars, but no one could; and if the earth rotated, then freely falling bodies should deviate from the vertical, and gunshots in opposite directions should not behave equally. The transition was also gradual insofar as such objections had to be answered piecemeal and new confirming evidence had to be found piecemeal. A significant step was the invention of the telescope and Galileo's discovery by its means of the moon's mountains, Jupiter's satellites, Venus's phases, and sunspots (in 1609-13). However, these telescopic discoveries did not resolve the issue; they merely refuted some anti-Copernican arguments and confirmed some aspects of Copernicanism. Another important step was Galileo's Dialogue on the Two Chief World Systems, Ptolemaic and Copernican (1632), which provided a critical examination of all arguments on both sides (save the religious ones), including a critique of the mechanical objections; this book showed that the scientific and philosophical evidence favored the earth's motion, which thus became more probable than the geostatic alternative; but, as Galileo realized, the case for the earth's motion was still not conclusive, since, for example, the stellar parallax objection could not be refuted.The sketch just given represents a consensus of recent scholarship. However, despite such scholarly consensus, there is at least one popular myth about the Copernican revolution that continues to be widespread: that conclusive proof of the earth's motion was provided by Copernicus himself, or the telescope, or Galileo's Dialogue, and that only religious superstition or ecclesiastic authoritarianism prevented the acceptance of Copernicanism.The aim of this book is to criticize this popular myth. It does so by examining the writings of the leading anti-Copernicans of the period and showing that they contained many good scientific arguments against the earth's motion. The principal author is, as the book's subtitle indicates, Giovanni Battista Riccioli, an Italian Jesuit who published the ambitious Almagestum novum (1651); a key topic was the critical examination of 126 arguments on both sides. Riccioli was building on the work of an earlier anti-Copernican, the Danish astronomer Tycho Brahe who, before the telescope, collected a mass of observational data that were unprecedented in quantity and quality; moreover, Tycho devised a hybrid worldview according to which the planets revolve around the sun, but the whole solar system and the fixed stars move around the central, motionless earth. A third author discussed by Graney is the Italian priest Francesco Ingoli, who in 1616 compiled an essay summarizing the astronomical, mechanical, and theological arguments against the earth's motion; this essay provided the basis for a decree by the Con- gregation of the Index declaring the earth's motion scientifically false and theologically contrary to scripture, and prohibiting Copernicus's book. …