Book excerpt: Can we know anything for certain? Dogmatists think we can, sceptics think we cannot, and epistemology is the great debate between them. Some dogmatists seek certainty in the deliverances of the senses. Sceptics object that the senses are not an adequate basis for certain knowledge. Other dogmatists seek certainty in the deliverances of pure reason. Sceptics object that rational self-evidence is no guarantee of truth. This book is an introductory and historically-based survey of the debate, siding for the most part with scepticism to show that the desire to vanquish it has often led to doctrines of idealism or anti-realism. Scepticism, science and common sense produce another view, fallibilism or critical rationalism: although we can have little or no certain knowledge, as the sceptics maintain, we can and do have plenty of conjectural knowledge. Fallibilism incorporates an uncompromising realism about perception, science, and the nature of truth.