Neither he nor Trump place any value in truth but for somewhat different reasons. Trump has psychological pathologies. He only processes reality through the filter of his narcissism. For Vance, whatever ethics he may have actually held in his Hillbilly Elegy days or before have been subsumed under the needs of his ambition. So for him it's more like game play, it's cynical, nihilistic. He's clever enough to formulate the inventions that serve his purposes into the form of arguments and he thinks that makes him persuasive. A sophist, if you take the classic definition of one who argues professionally to make the worse appear the better cause. In the CNN clip where he is defending spreading the Springfield stories you could see it was all just a game for him. I would have thought any other human with functional antenna should be able to see that and dismiss him out of hand. But for enough people, if they are being told what they want to hear, they turn off their brains.