Keith Johnstone’s Impro is ostensibly a book about iimprovisational theatre. Yet the book – in particular the introduction – goes both deeper and broader.

Here, for instance, is Johnstone on education:

People think of good and bad teachers as engaged in the same activity, as if education was a substance, and that bad teachers supply a little of the substance, and good teachers supply a lot. This makes it difficult to understand that education can be a destructive process and that bad teachers are wrecking talent, and that good and bad teachers are engaged in opposite activities [Improv, Keith Johnstone]

Johnson is absolutely correct for the kind of education he is thinking of – teaching art, or acting, or most situations where you could substitute ‘training’ for ‘teaching’.

He is, I think, only mostly correct when it comes to more academic education. The more the content resembles “one damn fact after another”, the more it can be taught by a bad teacher. If you attend a bad (but factually correct) history lecture, you will still come out with some basic information about the subject matter. Does that count as education? Debatable, but in my view it just barely clears the bar.

It helps to distinguish between knowledge-that and knowledge-how. Knowledge-that is factual knowledge which you can consciously explain. Knowledge-how is a skill, something you can do perhaps even without being able to explain it. I know that the Bastille was stormed on 14 July; I know how to ride a bicycle.

The academic system has a bias towards knowledge-that. A universtiy lecturer is arguable the highest-status teacher. Her work is one of the purest forms of teaching knowledge-that. The audience do not learn how to do anything more than sit on their bums and listen.

Yet, most of the value of a teacher is in teaching knowledge-how. I can skip a lecture and learn from a recording or a book. But if I skip an acting class, I will not be able to make up for it with time in the library.

The class where the teacher is most needed (acting, or dance, or woodwork) is also where a bad teacher can do most harm. Training a bad habit is more likely, and more harmful, than teaching a bad fact.

Knowledge-how is dangerous for the same reason it is powerful and wonderful. It changes how you see and understand and interact with the world, in a way that is hard to unpick. This is especially true of a topic like painting or drama, where the skill overlaps so completely with the rest of the self.