You are more likely to be right if you are somebody who shows a little doubt about something

By chance I just found the wonderful exchange below in the Minutes of Evidence of the House of Lords (i.e., the upper house of the British Parliament) Select Committee on Economic Affairs meeting of 14 February. It’s the record of the examination of witnesses on the state of public health research and its importance for the health of the population (don’t ask why I read this kind of stuff 🙂
The Lords have called Richard Peto, famous Oxford professor in medical statistics and epidemiology, to the stand. First Lord Skidelsky asks some questions about the epidemiological evidence behind the risks of smoking, and then Lord Vallance of Tummel (sic!) brings up the question of hospital acquired infections:

Sir Richard, I wonder if I may change the subject a little bit because you have already answered the question I was going to ask on smoking en passant. Could we move on to hospital acquired infections.

To which professor Peto answers:

I have been fairly useless on the previous questions and I am probably going to be even more useless on this.

Replies Lord Vallance of Tummel:

That is fine. Do not think that because you are being useless it is not helpful.

To which the Chairman adds:

You may take some comfort from the fact that with some people who are very assertive about what they believe we are not very convinced they are right either. We think you are more likely to be right if you are somebody who shows a little doubt about something.

Words of wisdom — stumbled upon in the minutes of a Select Committee of the House of Lords.