ARE you a self-actualiser: somebody who is driven by a pure love of knowledge, the greater moral good, or the unadulterated pursuit of beauty? Don't worry if you're not. The person who invented the concept, the psychologist Abraham Maslow, could list only 18 of them in modern times - a list that includes the likes of Jefferson, Einstein, and, naturally, himself.

Despite the apparent exclusivity of Maslow's definitions, his "hierarchy of needs", most often found expressed in pyramid form, has become, since it was first articulated in the 1950s, an essential part of psychological, sociological, and business-studies literature.

The hierarchy of needs identifies various layers of motivation in the psyche, starting with the need for food and other physical necessities; next, for safety; then love and esteem; and, finally, the blissful state of doing something for the sheer hell of it.

As Claudia Hammond discovered in Mind Changers (Radio 4, Friday), the theory is still much revered as a psychological template which asks positive questions of the human condition. Maslow's secretary at Brandeis University, in Massachusetts, led the plaudits, and it seemed that she was content to occupy a position on the penultimate level of the pyramid, motivated by the thrill of serving the guru.

Others, though, are less accepting of the Maslow model, not least because he eschewed any proper scientific investigation. While neuro-scientists have shown that the brain can indeed engage different motivational systems as it develops, none of this accounts for the danger-seeking mountaineer or the starving artist, who appear to leap to the top of the pyramid.

Nor does it explain the motivation of the parish priest, who might endure lack of privacy, and even opprobrium, as a result of his or her ministry. This was the question perplexing Laurie Taylor's guests on Thinking Allowed (Radio 4, Wednesday of last week), Dr Nigel Peyton and Dr Caroline Gatrell, who have recently published a book about the working lives of British clerics.

The issues discussed will be all too familiar: the requirement to be both intimate with parishioners and yet keeping some distance; the permeable barrier between the public and private; the disruption of family life. But you may not know that there is a sociological metaphor for this condition, coined by Michel Foucault: the panopticon. A panopticon is a kind of prison, designed so that the inmates can all be observed by the prison guards at any time, but without the inmates' knowing whether they are being watched.

As a way of describing the clerical life, the sociologists might have conceived something a little less depressing - perhaps the Bible may even have provided something suitable. But, in their study, some of their respondents echoed this kind of language, relating how they could never be "off-duty".

The surprising thing in all this discussion was that never once was faith mentioned - still less anything as dirty as calling. Listening to the discussion was like hearing people trying to describe the motor car to people who had no concept of the wheel.