At least as I read http://www.paulgraham.com/disagree.html http://www.paulgraham.com/disagree.html, it is an ontology for disagreements. Seiji's comment is not

At least as I read http://www.paulgraham.com/disagree.html http://www.paulgraham.com/disagree.html, it is an ontology for disagreements. Seiji's comment is not phrased as a disagreement, but rather a statement about how people will perceive your views. When the way people perceive a statement is important, predictions about how the statement will be perceived is as or more important than the truth of falsity of the statement. In terms of your hierarchy; I don't think that the take-home message from your hierarchy should be 'only ever say things that could be classified as DH6'. Discourse from authority or lack thereof has no place in scholarly correspondence of any form; everything should be based on the evidence available. However, non-experts often don't have the background or patience to evaluate claims about a certain field well enough to distinguish good reasoning from crank reasoning. Arguments from authority are therefore sometimes necessary to convince people on things they aren't experts in, and an argument against this authority can be an appropriate response (e.g. arguments like 'this person is saying things at odds with what 99.9% of scientists in the relevant field say, and are making claims that are outside their area of expertise', or 'this person has a serious conflict of interest in saying that'). The YouTube video doesn't work for me with either gnash or Adobe SWF player (YouTube normally works, I don't know why this one doesn't - maybe geographic restrictions) so I can't respond to the content of the video. The title is certainly an appeal to authority - "PG says this".