I propose that the power stroke of myosin, and many other biomolecular conformation changes, are driven by the pressure of a small number of molecules (principally, a phosphate ion) expanding a trap. I’ll show some computer demonstrations of the mechanism produced by my brother David, and outline how it fits with the wealth of experimental knowledge of the actin-myosin system. Finally I’ll address the underlying mathematical question of deriving a Langevin equation for the slow degrees of freedom of a large Hamiltonian system.

FRS, Director of Mathematical Interdisciplinary Research, University of Warwick & IHES