The most important thing to teach people about science is not a single principle, or any number of so-called facts. Rather, it is how science actually works - how it is done in theory, and how it is done in practice. Very few educated persons who are not practicing scientists have any understanding of this. As a consequence, the public does not understand the limitations of headline news discoveries. Nor does the public comprehend why what we accept as fact today, turns out to be a false premise in the future.

Much of the problem is that we do not teach science properly, at any level of the educational system. In lower grades, science is about memorising lots of facts. At the university level there are laboratories, which are little more than cookbook attempts to replicate experiments. But no one taking such classes gets any training in how to turn an idea into a testable hypothesis, and then how to formulate a rigorous experiment that can test the merits of that original idea.

Here is a brief anecdote to illustrate the level of ignorance about science. I once happened to sit on an aeroplane next to a former student, who had taken my developmental neurobiology course. It was several years after this student had graduated from my university. In the midst of our conversation, this seemingly intelligent young man enquired whether I was still studying the development of the brain or whether I had already succeeded in working it all out.

He actually thought that there was a limited cadre of facts that needed to be discovered, and that once this was done, there was no point in carrying on. In other words, he had no idea about how science works - that each new set of experiments naturally leads to other questions to be answered. Although I am an upbeat person, this young man's perspective depressed me quite a bit. Fortunately we were travelling first class, and I was able to brighten my mood with a stiff drink.

Leo Chalupa is coeditor of The Visual Neurosciences (buy this book from Amazon (UK) or Amazon (USA)).