Full Idea
The most extreme version of externalism would be one that held that the external condition required for justification is simply the truth of the belief in question.
Gist of Idea
Extreme externalism says no more justification is required than the truth of the belief
Source
Laurence Bonjour (Externalist Theories of Empirical Knowledge [1980], §II)
Book Reference
'Epistemology: Internalism and Externalism', ed/tr. Kornblith,Hilary [Blackwell 2001], p.15
A Reaction
The question is, why should we demand any more than this? The problem case is, traditionally, the lucky guess, but naturalist may say that these just don't occur with any regularity. We only get beliefs right because they are true.