Abstract
Until recently Euler was seen essentially as a mathematician than a physicist (modern meaning). After all, more than 60% of his work deals with pure mathematics, and even those whose object is mechanics and astronomy contain many sections that can be classified as mathematics. Today Euler’s role as a physicist, especially as a scholar of mechanics, is re-evaluated. One of the most prolific scientific writers, Euler treated all the themes of mathematics and physics, from astronomy to optics, from electricity to magnetism, and from hydraulics to mechanics to music, leaving an indelible mark in all sectors. He also wrote many pages of philosophy of nature, still of interest today because written with the sober language of the mathematician. As a matter of fact, it is impossible to distinguish the various facets of the polymath Euler. The present chapter focuses on mechanics, with particular attention to the epistemological, metaphysical, and natural philosophy aspects. The texts of Euler largely collected in his Opera omnia, still in progress, are analyzed avoiding as much as possible the use of glasses colored by modern concepts of epistemology. What is considered important has been to render his ideas clear to a modern reader. A particular attention has been devoted to the paper Anleitung zur Naturlehre of 1750, published only posthumously in 1862.