ABSTRACT
Peter Achinstein once argued that ‘Philosophical theories of evidence are (and ought to be) ignored by scientists’ (Achinstein 1995: title and passim). His reasons were that ‘such theories propose concepts of evidence that (a) are too weak to give scientists what they want from evidence and (b) make the evidential relationship a priori, whereas typically establishing whether e if true is evidence that h requires an empirical investigation.’ I wholeheartedly agree with (b), and will argue as much below. However, (a) is too strong a claim. It is certainly not the case that all existing philosophical theories of evidence propose concepts of evidence that are too weak. Some are also too strong, and most are both too strong and too weak at the same time. The issue with these theories is not that they propose concepts that are too weak but that they propose the wrong concepts: philosophical concepts that have little to do with the needs of practicing scientists.
