Full Idea
'Knowledge' is not a precise conception: it merges into 'probable opinion', and so a very precise definition should not be sought.
Gist of Idea
Knowledge cannot be precisely defined, as it merges into 'probable opinion'
Source
Bertrand Russell (Problems of Philosophy [1912], Ch.13)
Book Reference
Russell,Bertrand: 'The Problems of Philosophy' [OUP 1995], p.78
A Reaction
This announcement comes as a relief, after endless attempts (mainly by American academics) to give watertight, carefully worded definitions. It seems to me undeniable that what we will accept as knowledge is partly a matter of social negotiation.