The three-layered model of human political motivation I am proposing seems to me to be an improvement over existing models in several important areas, which I am happy to enumerate.
The first is that it treats humans as multi-faceted, which we are. The problem with very schematic thinking, from Hobbes onwards, is that it assumes a uniform quality within humanity that is not very apparent in real life as we live it. Human diversity in large and small things is constantly renewing and extending itself.
If we take one single explanatory motivating factor – be it the drive for profit, as it is for the economic right, or fear, as it was for Hobbes – we unrealistically restrict the range of situations we are explaining, and thus deny the range of responses they draw from us. We are not machines, and we do not react to everyone else in the same way all the time. Sometimes we think of direct personal benefits (interests), as we perceive them in context, sometimes we use wider experience (opinions), and sometimes we respond to the likeness or unlikeness of the people we are dealing with (identities) leading to prejudice.
In modern societies we can change our opinions and even our identities (or substantial elements of them). We cannot change our interests very easily, as defined by occupation or socio-economic class, but we can change the way we perceive those interests. All of these mutations are observable all the time in modern, pluralistic democratic societies. Nor are these alterations, or degrees of flexibility, such a bad thing. They must be there within any democratic society to prevent electoral processes becoming merely an occasional census.
Humans as political actors are composite, not monolithic, and we are constantly variable. Democracy fundamentally requires it, and any democratic theory must recognise this. Single source explanations for our behaviour, especially the kind that eliminate or despise our higher feelings and loyalties, cannot match well to human experiecne. Why are some people perpared to die for their beliefs, if we all rationally calculate our interest in monetary terms at all times? Or if self-preservation is always our greatest perceived ‘good’?