The analysis of Sternling and Scriven was restricted to the instability of planar interfaces, while, in reality, the interface can deform . The concomitant refraction of hydrodynamic streamlines can create local vortices and hydrodynamic instability that may ensue even in the absence of a surface tension gradient. The deformation of interface poses difficulties in tracking the evolution of a system as various paths are plausible. proposed that this problem can be resolved using the principle of non-equilibrium thermodynamics, in which the preferable paths are those that minimize the rate of entropy production.