Irritatingly, debating with the man invariably leads from his arguments to the person he is. It is like trying to have a conversation about a picture or an image with a colourblind man. He is looking at the same thing but, in his vision, there are colours missing and so in his mind the resulting image may be fundamentally different from reality. In the end, you find yourself insisting that the colours are really there and that he should just take your word for it. He, on the other hand, insists on describing what is in front of him without taking any notice of others telling him that his vision is flawed.
I particularly like the bit about him 're-setting' each time so that no intellectual progress is possible with the man over time even if you successfully refute some part of his argument... next day it is as if the previous debate never happened (kind of like watching old non-story-arc episodic SciFi shows that never referenced previous events).
Hmmm, does the above description remind you of anyone...?