The libel action by the British Chiropractors' Association against journalist Simon Singh has provoked a campaign to "Keep Libel Laws Out of Science". This unopposable title, and the campaign it heads, tend to put an unfortunate spin on the case. Singh is not being sued simply for claiming that chiropractice does not work, but for questioning the honesty of chiropractors - at least in their eyes. Anyone who feels they have been accused of dishonesty surely has a moral right to challenge that in the courts, if they stand to lose, or their accuser to gain, from the accusation.
Singh claimed, among other things, that the BCA "happily promotes bogus treatments." It may be debatable whether this phrase, or the article as a whole, actually does attribute dishonesty to chiropractors. But it would be wrong to see the case, as many do, simply as a battle between the forces of good science and evil quackery. Truth is a defence against libel. If the case came down to scientific evidence, then one hopes that Singh would have little to fear: on pain of hypocrisy, he surely possesses evidence sufficient (in his eyes, at least) to tip the balance of probabilities in favour of his own claims that chiropractice is without scientific basis. Indeed, if scientific claims were at issue, then presumably Singh's widely-advertised book on the subject would be a more obvious target for an action by the BCA.
But to prove that chiropractors don't believe their own claims would require more than just scientific evidence. It may be, of course, that Singh did not intend to accuse chiropractors of dishonesty. But if intentions alone determined meaning, then learning languages would be a great deal easier. The question is whether he did accuse chiropractors of dishonesty. If chiropractors believe he did, that helps both explain and justify their action.
Dr Alex Broadbent is Teaching Associate in the Department of History and Philosophy of Science at Cambridge University