Sir

I would like to add two important points to the discussions of C. P. Snow's 'two cultures' (Nature 459, 10 and 32–39; 2009).

First, it is not ignorance of the second law of thermodynamics that is the most serious gap in the education of many non-scientists, but a lack of basic understanding of how science works. For example, a recent UK survey, Public Attitudes to Science 2008, by Research Councils UK (http://tinyurl.com/o96lwg) showed that, although the public overwhelmingly believes that science makes the world a better place, a strong majority also maintains that no innovation should be licensed unless science has first proved it to be safe. As if it could! The controversy over the mumps–measles–rubella (MMR) vaccine showed that large sections of the public and, worse, the media either fail to understand the importance of evidence or have no respect for it.

Second, science is one of the pillars of civilization and liberal democracy, as that eminent philosopher of science, Karl Popper, convincingly argued. It is, he said, “one of the greatest spiritual adventures man has yet known”. Because science rejects claims to truth based on authority and depends on the criticism of established ideas, it is the enemy of autocracy. Because scientific knowledge is tentative and provisional, it is the enemy of dogma. Because it is the most effective way of learning about the physical world, it erodes superstition, ignorance and prejudice, which have been at the root of the denial of human rights throughout history, whether through racism, chauvinism or the suppression of the rights of women.

Nothing could have better illustrated the gap between cultures than literary critic F. R. Leavis's view that science is concerned only with “productivity, material standards of living, hygienic and technological progress”.