The best lecturer I had at medical school taught anatomy, was close to retirement, and did not give out lecture notes. He spent his entire lecture drawing: starting with the bones, he would add the muscles, viscera and have a discussion as to how this worked. He was impossible to take notes from unless you were, like him, an artist.

But he made the textbook comprehensible. Bruce Charlton suggests we don’t use slides: I do. Students expect them now. But they don’t get the stories unless they are in the lecture theatre or listen to the slides later.

I agree that innovations in teaching fail, and it is best if one lecturer teaches the entire course.

Lectures work; but nobody seems to know why. And the lack of an accepted rationale for the method seems to make people feel guilty about using lectures.

Typically lectures are taken for granted (which makes it unlikely that they will be improved); but the attitude is often hostile, and sporadic attempts are made to replace lectures with almost-anything-else in the name of innovative teaching: such experiments are usually short-lived… In modern mass higher education systems, it is impractical, and unaffordable, to replace lectures with a sufficient quantity of individual or small-group teaching. Attempts to do so, in any more than an ineffectual and token fashion, merely lead to less teaching of students.

Yet pragmatic realism about the lack of viable options is not a positive reason in favour of promoting lecturing as a valuable method in its own right; nor is it likely to guide or inspire good lecturing.

Perhaps the most convincing evidence of lectures’ specific effectiveness comes from what people actually do, rather than what people say. I find it highly significant that lectures have been especially used in teaching the most quantitative and systematic sciences, and for intensive professional training courses such as medicine, engineering and law.

In other words, lectures have been a focus of teaching in exactly the situations where transmission of knowledge is most vital, and in subjects where relevant learning is most validly measurable. This is an indirect argument in favour of their value.

(Of course, lectures will only get you so-far; and individual teaching by direct and sustained personal contact or ‘apprenticeship’ – supported by ‘drill’ or repeated practical exercises – remain absolutely essential methods for learning specialized and high level skills.)

What a lecture is not good for is clinical teaching. It can give knowledge, but not the art. That has to be taught at the bedside: on the ward round, in the tea room. It is why the clinical placements in medical training are essential, and the limiting factor for medical school size is the number of clinical placements available.

It is also why medical training is long, difficult and expensive. The educationalists cannot remove the need for the skilled clinician, as the profession is as much caught — like influenza — as taught. We may lose the essentials of education easily with innovation, and at our peril.