Meditations V.26

Let the ruling and master Reason of thy soul be proof against any motions in the flesh smooth or rough. Let it not mingle itself with them, but isolate and restrict those tendencies to their true spheres. But when in virtue of that other sympathetic connection these tendencies grow up into the mind as is to be expected in a single organism, then must thou not go about to resist the sensation, natural as it is, but see that thy ruling Reason adds no opinion of its own as to whether such is good or bad.