Full Idea
Some philosophers have been attracted to the view that, strictly speaking, what counts as evidence is not a set of physical objects or even experiences, but rather a set of believed propositions.
Gist of Idea
Maybe all evidence consists of beliefs, rather than of facts
Source
Timothy McGrew (Evidence [2011], 'Prop..')
Book Reference
'Routledge Companion to Epistemology', ed/tr. Bernecker,S/Pritchard,D [Routledge 2014], p.59
A Reaction
This may be right. However, as always, I think animals are a key test. Do animals respond to evidence? Even if they did, they might need to 'make sense' of what they experienced, and even formulate a non-linguistic proposition.
Related Idea
Idea 19681 If all evidence is propositional, what is the evidence for the proposition? Do we face a regress? [McGrew]