How do we know that we know?

The Nobel prize is perhaps the most prestigious award offered to scientists. More importantly, it is an opportunity for the public to learn about the questions that are currently puzzling scientists, and about the enormous progress that is made in different fields of science. This year for example, we learned about click chemistry and how it led to the development of a new class of reactions with important applications to both chemistry and biology.

The Nobel prize may give the impression that it is fairly straightforward to recognise genuine cases of scientific progress. However, this is misleading. The very idea of knowledge is extensively scrutinised in a distinct field of philosophy called epistemology. This aims to understand what constitutes knowledge; to specify how genuine knowledge differs from mere belief or opinion; and, to spell out what an adequate justification of a knowledge-claim requires.