Full Idea
Testimony must be reliable since its deliveries cohere both with input from other information routes in the formation of single beliefs, and with other types of beliefs in the formation of systems of belief.
Gist of Idea
Testimony is reliable if it coheres with evidence for a belief, and with other beliefs
Source
Martin Kusch (Knowledge by Agreement [2002], Ch. 4)
Book Reference
Kusch,Martin: 'Knowledge by Agreement' [OUP 2004], p.38
A Reaction
Kusch criticises this view (credited to C.A.J. Coady 1992) as too individualistic , but it sounds to me dead right. I take a major appeal of the coherence account of justification to be its capacity to extend seamlessly out into external testimony.