We extend the approach of the Feynman-Dyson proof of the Lorentz force law
to dissipative systems. The Feshbach-Tikochinsky equations for a damped har
monic oscillator are derived by considering localizable Poisson brackets fo
r dissipative systems on an extension of the velocity phase space by double
d phase space variables whose initial values are related to quantum effects
. The form of the Lagrangian is also determined. The solution involves a di
scussion of the inverse problem of the calculus of variations.