Carving Nature at its Joints? In order to map the future of biology we need to understand where we are and how we got there. Present day biology is the realization of the famous metaphor of the organism as a bete DEGREES machine elaborated by Descartes in Part V of the Discours, a realization far beyond what anyone in the seventeenth century could have im- ined. Until the middle of the nineteenth century that machine was an articulated collection of macroscopic parts, a system of gears and levers moving gasses, solids, and liquids, and causing some parts of the machine to move in response to...