Every understanding, every plausibility and everything implausible is bound to an observer, to a point in time and to a situation. Understanding is different to knowledge. Knowledge can be falsified (“There is no tree here!” … “Ouch, unfortunately there is!”). Understanding, in contrast, is not refutable, but only useful or not useful. Thus, if a counsellor understands something about the client, then the expression of this understanding is an offer to engage in dialogue and to explore if the correlations spoken of by the counsellor are helpful for the client and his guiding processes. Understanding is always a hypothesis. If the client can use it, it becomes an intervention. In psychotherapy or in personnel diagnostics, the usual way of pouring understanding into something which we call ‘expertise’, we consider, from a meta theory viewpoint, as dysfunctional regarding self-perception, and as generating inappropriate security. To put it bluntly: hypotheses serve the dialogue with the client, expertise serves those, that have commissioned them.