A couple of decades ago, the public felt that scientists provide absolute and objective truths about the material world. Today, we realise that scientists are only human, and so even scientific truths are fallible. However, the scientific method is still the best path to learning about the material world.

Scientists might sometimes misinterpret their observations. But ultimately, there is a way for them to check their theories, which is simply to compare theory with reality. A scientific theory can be checked, challenged, tested and probed. And if the theory stands up to all of its critics, then it is probably correct. But if the theory fails any test, then it has to be discarded, regardless of the seniority of its supporters or the beauty of the theory. As the nineteenth-century British biologist Thomas Henry Huxley put it, 'the tragedy of science is the slaying of a beautiful hypothesis by an ugly fact'.

Simon Singh is author of books including Big Bang: The Most Important Scientific Discovery of All Time and Why You Need to Know About It (buy this book from Amazon (UK) or Amazon (USA)), and Fermat's Last Theorem (buy this book from Amazon (UK) or Amazon (USA)). See his website.