ABSTRACT
This chapter discusses an interesting text from that period where Leibniz reflects on the idea of principles, in general, and the idea of principles of mechanics, in particular. It describes Principle of the Equality of Cause and Effect (PECE) and to some of the texts and concerns that led up to Leibniz's articulating the PECE in a series of texts written in 1675 and 1676. In a series of manuscripts, "De corporum concursu", Leibniz attempted to use that assumption to solve the problem of collision. In a manuscript dated May 1675, Leibniz considers a thought experiment where a pendulum bob transfers its force to raise a sphere of a given weight through a pulley, again attempting to figure out the equivalence between the power of a body in motion and the height to which a given weight can be raised. The chapter focuses on the way in which he uses principles in one particular area, his broadly mechanistic natural philosophy.
