They are if one defines truth as "beyond all reasonable doubt"
Which no sane person would.
It is the definition that any
reasonable person would agree with ...
And that is the basis of a civilised and cooperative society, I would suggest.
"Sanity" is far too subjective and personal a concept to be used.
I may think that Levee, for example, is "bat shit crazy" ...
And he is free to think the same of me ...
What we have to do is to learn to live and interact with each other in a
reasonable way.
Idealists may disagree, but idealists are some of the most dangerous people around.