Full Idea
The radical externalists' key notion is 'reliability', which is a normative condition governing adequate performance, involving reference to a range of conditions which we decide rather than discover.
Gist of Idea
Externalist reliability refers to a range of conventional conditions
Source
Michael Williams (Problems of Knowledge [2001], Ch. 2)
Book Reference
Williams,Michael: 'Problems of Knowledge' [OUP 2001], p.33
A Reaction
If we can decide whether a source is reliable, we can also decide whether a reliable source has performed well on this occasion, and that will always take precedence.