Since the Holy Writ is true, and all truth agrees with truth, the truth of Holy Writ cannot be contrary to the truth obtained by reason and experiment.  This being true, it is the business of the judicious expositor to find the true meaning of scriptural passages which must accord with the conclusions of observation and experiment, and care must be taken that the work of exposition do not fall into foolish and ignorant hands.  It must be remembered that there are very few men capable of understanding both the sacred Scriptures and science, and that there are many with a superficial knowledge of the Scriptures and with no knowledge of science who would fain arrogate to themselves the power of decreeing upon all questions of nature.  As St. Jerome writes:  “The talking old woman, the dotard, the garrulous sophist, all venture upon, lacerate, teach, before they have learnt.  Others, induced by pride, dive into hard words, and philosophate among women touching the Holy Scriptures.  Others (oh, shameful!) learn of women what they teach to men.”

I will not rank among these same secular writers any theologists whom I repute to be men of profound learning and sober manners, and therefore hold in great esteem and veneration; yet it vexes me when they would constrain science by the authority of the Scriptures, and yet do not consider themselves bound to answer reason and experiment.  It is true that theology is the queen of all the sciences, but queen only in the sense that she deals with high matters revealed in noble ways, and if she condescends not to study the more humble matters of the inferior sciences she ought not to arrogate to herself the right to judge them; for this would be as if an autocratic prince, being neither physician nor architect, should undertake to administer medicines and erect buildings to the danger of the lives of his subjects.

Again, to command the professors of astronomy to confute their own observations is to enjoin an impossibility, for it is to command them not to see what they do see, and not to understand what they do understand, and to find what they do not discover.  I would entreat the wise and prudent fathers to consider the difference between matters of opinion and matters of demonstration, for demonstrated conclusions touching the things of nature and of the heavens cannot be changed with the same facility as opinions touching what is lawful in a contract, bargain, or bill of exchange.  Your highness knows what happened to the late professor of mathematics in the University of Pisa—­how, believing that the Copernican doctrine was false, he started to confute it, but in his study became convinced of its truth.

In order to suppress the Copernican doctrine, it would be necessary not only to prohibit the book of Copernicus and the writings of authors who agree with him, but to interdict the whole science of astronomy, and even to forbid men to look at the sky lest they might see Mars and Venus at very varying distances from the earth, and discover Venus at one time crescent, at another time round, or make other observations irreconcilable with the Ptolemaic system.