The American physicist Richard Feynman once said that if all scientific knowledge were wiped out, except for one fact, then the most important fact is that the world is made of atoms. Of course, that fact is not hard to understand.

In my opinion, the hardest thing for people to grasp is not so much this or that technical concept, but the very process of science itself. The essence of the scientific method is that there is an actually existing world out there, which is ordered in an intelligible way. The job of the scientist is to describe that order, in the best possible manner. Science is not about right and wrong, about truth, or even about reality. It is about providing reliable descriptions of the world that enable us to make new discoveries.

Part of this is that science links phenomena that are not obviously connected when we casually observe the world. So scientific knowledge is deep, as well as broad. The fact that there exists a hidden subtext of nature - a set of abstract mathematical principles, linking all phenomena - lies at the heart of science. But this aspect is not often grasped, even by scientists.

The key elements of the scientific method are scepticism, critical enquiry, subjecting hypotheses to rigorous tests, the importance of advancing explanations that are open to falsification, and the need to change and adapt concepts in the light of new facts. These elements set science apart, as the finest example of collective human endeavour, even though it is not infallible. If only we could apply such lofty ideals to all aspects of human society.

Paul Davies is author of books including About Time: Einstein's Unfinished Revolution (buy this book from Amazon (UK) or Amazon (USA)), and The Mind of God: Science and the Search for Ultimate Meaning (buy this book from Amazon (UK) or Amazon (USA)). See his website.