> That seems to remove the possibility to know anything from a written text including science, history, autobiographies, and other forms of non-fiction.
Things aren't true because they're written, they're true because they can be verified as true; writing merely adds the possibility to pass on the knowledge required to verify a truth. Absent re-verification, nothing is true simply because someone wrote it down.
I may have been in the Toyota factory and even met the engineers who designed the cars. That doesn't mean I understand the full intent of Toyota's board of directors.