Abstract

In this paper one aspect of Leibniz' optical ideas, the law of refraction, is the main topic. This law had been formulated before him by Snellius, Descartes and Fermat. Their mathematical equations are analogous in the relations between the geometrical parameters and the optical resistances, but they differ concerning the velocities of light. From the Leibnitian point of view this situation has its reasons in uncompletely developed principles. Leibniz had shown that the solution of this problem requires a new metaphysics as well as other mathematical, namely infinitesimal methods, which are connected in Leibniz by his dynamics. As one of the influences of his dynamical statement, the beginning of a new type of physical explanation will be demonstrated, which replaced the construction of mechanical models in the 18th century