Full Idea
It may be that all 'knowledge' attributions have the same truth conditions, but people apply contextually varying standards. The most plausible standard for truth is very high, but not unreachably high.
Gist of Idea
Maybe knowledge has fixed standards (high, but attainable), although people apply contextual standards
Source
Earl Conee (Contextualism Contested (and reply) [2005], 'Loose')
Book Reference
'Contemporary Debates in Epistemology (2nd ed)', ed/tr. Steup/Turri/Sosa [Wiley Blackwell 2014], p.65
A Reaction
This is the 'invariantist' alternative to contextualism about knowledge. Is it a standard 'for truth'? Either it is or it isn't true, so there isn't a standard. I take the standard to concern the justification.