Full Idea
It can be argued that testimony is non-reductive because it relies on the fact that whatever is intelligible is likely to come from a rational source, and that rational sources, by their very nature, tend towards the truth.
Gist of Idea
A foundation is what is intelligible, hence from a rational source, and tending towards truth
Source
Martin Kusch (Knowledge by Agreement [2002], Ch. 4 n7)
Book Reference
Kusch,Martin: 'Knowledge by Agreement' [OUP 2004], p.37
A Reaction
[He cites Tyler Burge 1993, 1997] If this makes testimony non-reductive, how would one assess whether the testimony is 'intelligible'?