If anyone can invent a straight line, that deserves some praise. Connecting that to education and to humanity, and, on the way, making use of snapshots, alcoholics and old age, suggests real wisdom.

Phillida (Phil) Salmon is a psychologist. Teachers, like psychologists, are sensitive to the reputation of their profession. Is teaching easy or difficult, subversive or compliant? Is psychology arcane or courting popularity, mechanistic or over-sympathetic? It is opposites like these that the psychologist Phillida Salmon illuminates.

For every teacher excited by the job and who loves learning, there is a cynic and fact-monger. For every enthusiastic and creative child, there is a disruptive and bored pupil. Each of these opposites exist in the same person. So, how do you understand and live with both? How do we all change?

Draw a straight line and put words representing opposites at each end. Happy and sad, successful and unsuccessful, co-operative and uncooperative, good teacher and bad teacher. Anything. That is the start, the Salmon line.

Where are you on the line, now? Where would you like to be in the future? Mark these points. Now write, or better still talk, about how you think you will get from one point to the other. In the talk is the learning.

How often are schools filled with what the philosopher Martin Buber called “monologue disguised as dialogue”: people asking questions to which nobody wants to know the answers or guessing what the questioner wants to hear? The Salmon line provides a way of talking to each other by allowing a way of talking about ourselves.

One of the strangest discoveries Phil Salmon made was how people recognise themselves in photographs. Take a set of portraits, then ask friends which one they most look like. You may find, as Phil did when working with alcoholics, that they do not pick the same photographs you would have picked for them. Ask them which they would most like to resemble, who is their ideal, and they will often choose the photographs you think most resembles each of them.

We all have a real self and an ideal self and we have real and ideal versions of schools. The surprise is that the ideal self, the self that looks down its nose at our everyday follies, is every bit a part of us as what we think of as the real self. We are not simply cynical and empty or enthusiastic and creative. We are both and we are able to move from one to the other if we talk about it and if we sense others are listening.

Dialogue again, helped by the Salmon line, helping to create communities.

The great philosopher of community John Macmurray wrote about how schools were communities, like families or religious groups, and not societies. In societies, people work for an external purpose, making money or meeting targets or completing tasks; in communities, people treat each other as whole human beings, as ends in themselves. Schools provide a continuing personal exchange between two generations. “We may act as though we were teaching arithmetic or history. In fact we are teaching people. The arithmetic or the history is merely a medium through which a personal intercourse is established,” he argued.

The Government has recently realised that the child and personalisation is important, rather than just exam results. Macmurray, said to be Tony Blair’s guru, might stop spinning in his grave long enough to give a wry smile.

Other educationists who have helped me understand schools include Harry Daniels, Jean Rudduck, Jean Lave and Etienne Wenger.

Daniels, who has the Russian psychologist Lev Vygotsky looking over his shoulder, writes of the difference between schools where pupils paint what they see and those where pupils paint what the teacher sees.

Rudduck asks us to listen to children. I think it’s shocking that we need reminding.

Lave and Wenger write with passion about communities of practice and how bad schools can be at teaching anything other than schooling itself.

The practice that schools should be communing about seems to me to be best described by Phil Salmon. Children are not just preparing for adulthood, any more than adults are just workers or the elderly are just declining towards death. We are all living, and moving and learning while we do.

If I were to put educationists on a Salmon line, Phil and the others named here would be at one end. Any educationist who claims to know all the answers, who talks about customers and about exams as though that were all there was to education, would be at the other end.

It is a mark of the generosity of Phil’s philosophy that even those who sit towards the inhuman end all have better versions of themselves further along the line. We just need to keep the dialogue going.

Dr Julian Stern is head of the centre for educational studies at Hull university