I read with interest the debate about Iran's scientific development in your Editorial and Correspondence (Nature 442, 719–720; 2006). The Correspondence authors argued that Iran poses a danger. However, I believe that, as scientists, we have a duty to remain rational, believing in facts and distrusting rhetoric — whether from Iran, the United States or elsewhere.
I do not believe that evidence has been produced to show Iran's nuclear-technology programme is being used for military purposes. By relying on words, and hence on belief rather than evidence, we would elevate diplomacy and politics to the level of faith, whereas history teaches us that they should be kept in the realm of rationality. Francisco Goya told us in a famous etching that “the sleep of reason produces monsters”. Let's not make that picture into a prophecy.