Can we trust any source?
In practical terms I think we have to, because we could spend our entire lives checking everything.
“question everything” is pretty impractical ?
I have some rough rules of thumbs,
- One is if I catch a source out on what seems to be a deliberate lie, that undermines their credibility for me.
- Another is if sources refuse to cite their sources or take on their philosophical burden of proof – same deal
It’s not a moral judgement, there are plenty of people writing poetry and propaganda who are post-truth 
good on them