Understanding Galileo's Inquiries About the Law of Inertia

The purpose of this research is to gain a better understanding of the role of abstraction and idealization in Galileo's scientific inquiries about the law of inertia, which occupies an important position in the history of science. We argue that although the terms "abstraction" and "idealization" are variously described in the recent literature, the concepts must be adopted to highlight important epistemological problems. In particular, we illustrate the importance of abstraction and idealization for the formation of the law of inertia by establishing a distinction between two types of entities: quasi-ideal entities and idealized entities. These theoretical laws should therefore be justified, using deduction and induction, through quasi-idealized entities based on data from the everyday world.