ABSTRACT
This chapter discusses in detail the concept of scientific evidence, focusing on what makes it different from other sorts of evidence, via examination of the historical example of polio vaccine research. It is essential to have a conceptual understanding of the notion of scientific evidence, because it is sometimes misunderstood, even by scientists themselves, that there is no rule of logic that can decide for us the question of what counts as scientific evidence – or indeed as evidence in any given domain.
