....there is always a gap between the model and the reality. The clarity of contour and symbol in the map is quite other than the earthy, fractal grain of the territory. The model is only a guideline in the mind, it is not a precise blueprint or programme for behaviour.

Behaviour is situational, idiosyncratic and above all practical – knowing how to respond to present reality. There is always a gap – a necessary and important gap – between knowing how to do something in deed, and describing how to do it. Human skills are maculate skills, enriched by earthy granulation: they are more basic and worthwhile than any seemingly immaculate descriptions that may service them.

John Heron “Helping The Client” A creative practical guide – Chapter 2, page 14