Paul Keating still quotes his early mentor, Jack Lang: ''In the race of life, always back self-interest - at least you know it's trying''. This may be why, as treasurer, Keating so readily embraced economic rationalism. The economists' working model assumes the self-interest of the individual is the sole force that makes the world turn.
Fortunately, the latest research tells us it's not that simple.
I can't go on a sight-seeing holiday without taking a few good books for a little intellectual sustenance at the end of the day. One book I took this time was a ripper, The Righteous Mind: Why good people are divided by politics and religion, by Jonathan Haidt, a moral psychologist at the University of Virginia.
Haidt (pronounced Height) says decades of research by political scientists have concluded that self-interest is a weak predictor of voters' policy preferences.
Why? Because people care about the groups they belong to - whether they be racial, regional, religious or political. They seem to be asking themselves not ''what's in it for me?'' but ''what's in it for my group?''. Political opinions function as ''badges of social membership''.
Whereas the old view was that natural selection had caused us to evolve into self-seeking competitors, Haidt argues we're more accurately thought of as ''homo duplex'' - a creature who exists at two levels: as an individual and as part of the larger society.
Human nature is mostly selfish: our minds contain a variety of mental mechanisms that make us adept at promoting our own interests, in competition with our peers, he says. But human nature is also ''groupish'': our minds contain a variety of mental mechanisms that make us adept at promoting our group's interests, in competition with other groups.
''We evolved to live in groups. Our minds were designed not only to help us win the competition within our groups, but also to help us unite with those in our group to win competitions across groups,'' he says. ''We are not saints, but we are sometimes good team players.''
All this goes a long way towards explaining the psychological roots of morality. Haidt defines moral systems as interlocking sets of values, norms, practices and institutions that work together to suppress or regulate self-interest and make co-operative societies possible.
His research leads him to believe moral intuitions arise automatically and almost instantaneously in our minds, long before moral reasoning has a chance to get started. Moral reasoning is not something we do to figure out the truth. Rather, it's a skill we evolved to further our social agendas - to justify our own actions and defend the teams we belong to.
Human nature is intrinsically moral, but it's also intrinsically moralistic, critical and judgmental.
''Our righteous minds made it possible for human beings - but no other animals - to produce large co-operative groups, tribes and nations without the glue of kinship,'' he says. ''But at the same time, our righteous minds guarantee that our co-operative groups will always be cursed by moralistic strife.''
We're much more aware of other people's moral shortcomings than our own, often making us ''selfish hypocrites so skilled at putting on a show of virtue that we fool even ourselves''.
Haidt says one of the hardest problems humans face is co-operation without kinship. We instinctively co-operate with people to whom we're directly related, but co-operation within wider groups carries the ever-present temptation to ''free-ride'' - to enjoy the benefits co-operation brings while avoiding pulling our weight.
The more people free-ride, and the more we see others failing to pull their weight, the more co-operation breaks down and we all forgo the benefits it could bring.
Haidt argues morality is, in large part, an evolved solution to the free-rider problem. We develop norms of acceptable, co-operative behaviour and find ways to sanction people who aren't co-operating.
His empirical research into the moral sentiments of people from around the world leads him to identify six dimensions to people's moral concerns. First is care/harm; we are sensitive to signs of suffering and need, and despise cruelty. Second is liberty/oppression; we resent attempts to dominate us. Third is fairness/cheating; people should be rewarded or punished in proportion to their deeds.
Then there's loyalty/betrayal; we trust and reward team players, but want to sanction those who betray the group. Next is authority/subversion; we recognise rank or status and disapprove of those not behaving properly, given their position. Finally there's sanctity/degradation; we care about what we do with our bodies and what we put into them.
Haidt believes these moral concerns are shared by people regardless of their culture, nationality or wealth. But, of course, people interpret them differently and put more weight on some than others.
Our differing moral emphases are reflected in our differing political sympathies. So the unending battle between small-L liberal and conservative policies is a manifestation of ''deeply conflicting but equally heartfelt visions of the good society''.
Haidt finds that small-L liberals' moral concerns are limited to just the first three dimensions: they care deeply about the harm suffered by minorities and the needs of the poor, about oppression and about fairness.
Conservatives, on the other hand, care about all six dimensions. Their most sacred value is to ''preserve the institutions and traditions that sustain a moral community''. So they worry also about maintaining loyalty, acceptance of authority and the sanctity of our bodies.
The conservatives' broader range of moral concerns means they understand the motivations of liberals better than liberals understand the motives of conservatives.
Haidt argues the community benefits from the ever-present tension between the two sides - each emphasises important aspects of maintaining a good society - if only we could restore a greater degree of civility between the contending parties.
Ross Gittins is the Sydney Morning Herald's economics editor.