TO THE READER CONCERNING THE HYPOTHESES OF THIS WORK.

A perforated library stamp reading "BOSTON PUBLIC LIBRARY" is visible through the center-left of the page, and various handwritten shelf marks from the 19th century appear at the bottom, marking the book's history as a physical object in a library collection.

An ornamental woodcut initial 'N' features a figure, likely a scholar or astronomer, seated at a desk with books in a study, representing the labor of learning and observation.

I do not doubt that certain learned men, now that the report of the novelty of the hypotheses The word "hypothesis" here refers to the underlying mathematical assumptions of the system. of this work has been made public—namely, that it establishes that the Earth moves and that the Sun truly stands still in the middle of the universe—will be deeply offended and think that the liberal arts term: "liberal arts" The classical curriculum of study, which included astronomy and geometry., which were correctly established long ago, ought not to be thrown into confusion. However, if they are willing to weigh the matter exactly, they will find that the author of this work has committed nothing that deserves blame. For it is the duty of an astronomer to gather the history of the heavenly motions through diligent and skillful observation. Then, since he can by no means reach the true causes of these motions, he may think up and devise any hypotheses he likes, provided that, when they are assumed, these same motions can be correctly calculated from the principles of geometry, both for the future and for the past. This artist The writer uses "artist" (artifex) here to mean a skilled practitioner of a technical craft like astronomy. has excelled at both of these tasks. For it is not necessary that these hypotheses be true, or even probable; it is enough if they provide a calculation that matches the observations.

Unless, perhaps, someone is so ignorant of geometry and optics that he considers the epicycle term: "epicycle" A small circle whose center moves around the circumference of a larger one; used in ancient astronomy to explain the complex movements of planets. of Venus to be probable, or believes it is the reason why Venus sometimes precedes and sometimes follows the Sun by forty degrees or more. For who does not see that if this were assumed, it would necessarily follow that the diameter of the star at perigee original Greek: "περιγείῳ"; the point where a planet is closest to the Earth. would appear more than four times larger, and the body of the star itself more than sixteen times larger, than at apogee original Greek: "ἀπογείῳ"; the point where a planet is farthest from the Earth.? Yet the experience of every age contradicts this. There are other things in this discipline no less absurd, which there is no need to examine at present. For it is clear enough that this art is simply and completely ignorant of the causes of the seemingly irregular motions. And if it devises any causes by imagination—as it certainly devises many—it does not do so to persuade anyone that it is so in reality, but only to establish a correct method of calculation. Since sometimes different hypotheses are offered for one and the same motion (as in the motion of the Sun, both eccentricity term: "eccentricity" A model where the orbit's center is slightly offset from the Earth. and the epicycle), the astronomer will most likely seize upon the one that is easiest to understand. The philosopher In this context, a "philosopher" refers to a "natural philosopher" or physicist, someone concerned with the actual physical nature of the world rather than just mathematical models., perhaps, [seeks] more [probability]...