The struggle undertaken by Galileo Galilei against Aristotelian physics—and his subsequent defense of Nicolaus Copernicus’s theories—led the Pisan scientist to bring about the so-called modern scientific revolution and to lay the foundations of the experimental method, the fundamental result of which was to deprive the natural world of subjective qualities and to reconfigure it in purely quantitative terms. On the purely historical level, agreement among historians of science and philosophy is almost unanimous, while the same cannot be said for questions concerning interpretations of Galilei’s modus operandi and the basic philosophical options adopted by Galilei during his demolition of the entire Aristotelian-scholastic framework. Not all experts in the Galilean thought or of science, in fact, agree in tracing the Galilean reflection within the Platonic tradition, but one authoritative voice that has instead argued for its deep intertwining between Plato and Galilei is the German philosopher Ernst Cassirer. In this contribution I will attempt to demonstrate, partly considering two unpublished manuscripts of Cassirer, the plausibility of the Cassirerian thesis about Galilei’s physical Platonism.