Recording of a lecture delivered on September 26, 2025, by Annapolis Dean Joseph Macfarland as part of the Formal Lecture Series.

Mr. Macfarland offers the following description: "According to Galileo, the grand book of the universe standing before our eyes is written in the language of mathematics, in the characters of geometrical figures. On account of this conception of nature as fundamentally mathematical, he is taken to be a sort of founder of modern science and philosophy. By one account, the subsequent rapid progress of mathematical methods entails a forgetfulness of, or distrust of, mere appearances. The things known objectively, that is, mathematically, are not what they seem. This way of thinking seems fitting to the replacement of the Ptolemaic system by the Copernican one. The lecture will consider a few examples of how Galileo takes in what is before his eyes and thinks about it, and it will consider some limits to his efforts to account for phenomena mathematically. These characteristics of his natural philosophy will be viewed within the context of his attempt to secure a freedom to philosophize. The lecture will focus on his Dialogue Concerning the Two Chief World Systems, Ptolemaic and Copernican, with attention to his letter to Christina of Lorraine. No familiarity with either text will be presupposed."