The Post Truth Movement can be broken down into three rational outcomes:
1) People are selectively bias in which content they believe is ‘True’ meaning their is an ideological divide (or most likely divisions), that will eventually lead to a material conclusion. Historical analysis would suggest that this would most likely take form in conflict.
2) Everyone excepts the epistemological limits and arrives to the conclusion that there never was a ‘Truth’ they could perceive. If this is the case, we would have a moral obligation to only choose the most ethical option when presented with Crisis and surrender blindly to utilitarianism, if the goal of human societies are to maximise liberty for all people. This will inevitably lead to an authoritarian ruling on what can be perceived as True, stripping us of our agency in accessing knowledge.
3) There is an agenda behind it that seeks supremacy from its actions. I.e autonomy is stripped and people are being willingly manipulated by forces who push the movement.