"Sensitivity is the principle of all action. A being, albeit animated, who would feel nothing, would never act, for what would its motive for acting be? God himself is sensitive since he acts. All men are therefore sensitive, and perhaps to the same degree, but not in the same manner. There is a purely passive physical and organic sensitivity which seems to have as its end only the preservation of our bodies and of our species through the direction of pleasure and pain. There is another sensitivity that I call active and moral which is nothing other than the faculty of attaching our affections to beings who are foreign to us. This type, about which study of nerve pairs teaches nothing, seems to offer a fairly clear analogy for souls to the magnetic faculty of bodies. Its strength is in proportion to the relationships we feel between ourselves and other beings, and depending on the nature of these relationships it sometimes acts positively by attraction, sometimes negatively by repulsion, like the poles of a magnet. The positive or attracting action is the simple work of nature, which seeks to extend and reinforce the feeling of our being; the negative or repelling action, which compresses and diminishes the being of another, is a combination produced by reflection. From the former arise all the loving and gentle passions, and from the latter all the hateful and cruel passions."