this is actually an important field that is today missing when we see the amount of data we need to digest. How to categorize internet data that emerge on internet.
This is a big challenge.
In real world you trust the source then the information that goes from the source.
If you dont have enough information on the source then you look for trusted source advise on this source, or on this info. System being built step by step.
However a source can be compromised. This trusted source can be challenged anytime by the system by adequate collegial vote of trusted sources.
There is no false or true fact without source. Someone has to see it at first stance.