as far as anyone knows
as far as (one) knows
As much as one knows about a certain situation and/or at a particular time. As far as I know, Scott is coming today. Has anyone else heard from him? Thanksgiving dinner has been pushed to 4:00, as far as we know. But I can call Carol and try to get an update, if that makes you feel better.
as far as anyone knowsand so far as anyone knows; to the best of one's knowledge
to the limits of anyone's knowledge. (The anyone can be replaced with a more specific noun or pronoun.) As far as anyone knows, this is the last of the great herds of buffalo. Far as I know, this is the best spot to sit. Q: Are the trains on time? A: To the best of my knowledge, all the trains are on time today.