The most important quality of science is its self-correcting capacity. Science deals in doubt, leaving infallibility to the various mutually incompatible ideologies of this world, whether religious or political. But there are degrees of doubt, and the scientific attitude is that it is reasonable to act as if a theory were true, while accepting that it may be false - if it is the best tested theory available so far not found wanting.

This is surely a lesson that we ought to understand, in this centenary year of the theory of relativity. We do not think less of Isaac Newton because Albert Einstein showed his laws to be false - if highly accurate, in everyday circumstances - approximations to some more general system. When a putative science starts stressing proof, evidence and tests, then this is a sign that it is finally beginning to deserve the name 'science'.

In this sense, it can be said that therapeutic medicine began to become a science just before the middle of the twentieth century, with the introduction of randomised clinical trials. If I could teach the world one thing about science, it would be that critical examination, although not a guaranteed path to enlightenment, is the most sensible strategy for proceeding in an uncertain world.

Stephen Senn is author of books including Dicing with Death: Chance, Risk and Health (buy this book from Amazon (UK) or Amazon (USA)). See his website.