The economy of nature - Maupertuis and Euler on the principle of least action

The principle of least action was discovered in the realm of optics (Maupertuis) and in the mathematical properties of a body moving within a framework of forces (Euler). Both Euler and Maupertuis rely on a metaphysical understanding of nature to justify the expansion of this principle into a general principle of physics. In this paper, I argue that both believe that nature itself uses no unnecessary means for its ends, thus is economical. The principle of least action can be understood as the attempt to integrate this metaphysical idea of an " economy of nature" into the realm of science.