Can common and definitive principles of reason and morality be found?

Playlist: https://www.youtube.com/playlist?list=PL3hRi89YhwZab1XoxgaK4kCw4VjGF8qfL

So far we have reached this conclusion that the only reliable way to examine the claim of those who present themselves as God's prophets is measuring the content of their message against clear and common rational principles. But the problem here is that practically there is no common point in the instances of reason and morality, and each person considers his opinion and method logical and moral.

We understand the seriousness of the problem more when we see that even great and common values like justice and truthfulness also face different interpretations, restrictions and justifications in various cultures, regions and periods, and perhaps one group considers an action just and honest while another group considers it immoral behavior.

In these circumstances, the only solution that remains is that while understanding the limitations of the human epistemological system, each person without considering his opinion as absolute truth and his opponents as enemies of truth, should take as the criterion for his evaluations what he identifies after dialogue and hearing various viewpoints.

Of course, in this context, evidences like the incorrectness of contradiction and acceptable values like the golden rule of morality help us not hesitate in denying those who have contradictory teachings or prescribe behavior they wouldn't like for themselves, and to accept the claim of someone from whose teachings we get better results in practice.