" . . . Neither ecological nor social engineering will lead us to a conflict-free, simple path . . . Utilitarians and others who simply advise us to be happy are unhelpful, because we almost always have to make a choice either between different kinds of happiness--different things to be happy _about_--or between these and other things we want, which nothing to do with happiness.

. . . Do we find ourselves a species naturally free from conflict? We do not. There has not, apparently, been in our evolution a kind of rationalization which might seem a possible solution to problems of conflict--namely, a takeover by some major motive, such as the desire for future pleasure, which would automatically rule out all competing desires. Instead, what has developed is our intelligence. And this in some ways makes matters worse, since it shows us many desirable things that we would not otherwise have thought of, as well as the quite sufficient number we knew about for a start. In compensation, however, it does help us to arbitrate. Rules and principles, standards and ideals emerge as part of a priority system by which we guide ourselves through the jungle. They never make the job easy--desires that we put low on our priority system do not merely vanish--but they make it possible. And it is in working out these concepts more fully, in trying to extend their usefulness, that moral philosophy begins. Were there no conflict, it [moral philosophy] could never have arisen.

The motivation of living creatures does got boil down to any single basic force, not even an 'instinct of self-preservation.' It is a complex pattern of separate elements, balanced roughly in the constitution of the species, but always liable to need adjusting. Creatures really have divergent and conflicting desires. Their distinct motives are not (usually) wishes for survival or for means to survival, but for various particular things to be done and obtained while surviving. And these can always conflict. Motivation is fundamentally plural. . . An obsessive creature dominated constantly by one kind of motive, would not survive.

All moral doctrine, all practical suggestions about how we ought to live, depend on some belief about what human nature is like.

The traditional business of moral philosophy is attempting to understand, clarify, relate, and harmonize so far as possible the claims arising from different sides of our nature.

. . . One motive does not necessarily replace another smoothly and unremarked. There is _ambivalence_, conflict behavior. "

― Mary Midgley , Beast and Man: The Roots of Human Nature