Full Idea
If justification is the fundamental epistemic norm of belief, and a belief ought to constitute knowledge, then justification should be understood in terms of knowledge too.
Gist of Idea
Belief explains justification, and knowledge explains belief, so knowledge explains justification
Source
Timothy Williamson (Knowledge First (and reply) [2014], p.5)
Book Reference
'Contemporary Debates in Epistemology (2nd ed)', ed/tr. Steup/Turri/Sosa [Wiley Blackwell 2014], p.5
A Reaction
If we are looking for the primitive norm which motivates the whole epistemic game, then I am thinking that truth might well play that role better than knowledge. TW would have to reply that it is the 'grasped truth', rather than the 'theoretical truth'.