Sir

Søren Holm and John Harris argue that the precautionary principle stifles discovery (Nature 400, 398; 1999). I believe such a judgement to rely on a misunderstanding of the link between science and progress.

Discovery is by definition never self- evident: when a problem arises, the most apparently ready-made ways to solve it are likely to be the least productive in genuine novelty. This is precisely where moral issues come in, in science as in life in general. Real progress originates from the refusal to take a path that would threaten one's own moral choices and values. It is in such a situation, which to me is the essence of science as a daughter of ethics, that other ways do show up, not previously thought of, which lead to discovery. It is precisely the moral problem coming to the researcher's consciousness that alerts him to the fact that he is able to find another way. Not listening to the voice of consciousness in such a situation thus leads to missed discoveries. Therefore it is precisely in research that ethical principles are most useful.

So the precautionary principle should be viewed rather as a guide to avoid wrong directions, opening the way to better ones.