What's the criterion for the truth of a philosophical proposition? In philosophy as a general discipline, not in different doctrines.
In science, it's the observed reality; in religion, it's the God's sayings revealed to its prophet and gathered in a book such as Bible, Quran, etc; in art, the matter is not the truth but beauty and seemingly the criterion should be the audience's experience when being exposed to the art work.
But in philosophy what is it?