My private hypothesis, with no evidence, is that the strength of American conservatism is related to this strong puritan heritage. We simply don't have the same thing over here in the UK.
I've been assering that (with equal lack of objective evidence) for a long time. America, as a country, has an unbelievable preoccupation with sex, "morality", and militarism in the face of conflicting viewpoints, all of which is paralleled with the Puritan mindset.
Re ground rules, the possibility of error is assumed among scientists, but it is not assumed by non-scientists and they tend to interpret scientific statements as definitely true('scientifically proven'). So I think when debating with non-scientists this assumption needs to be made explicit.
Again, I agree. When a sicentist is speaking to a colleague, they will often assume the other person knows there is a tentativity, and will probably only mention it when speaking in terms of a margin of error of X percent. When speaking to a lay audience, this is one of the facts about science that needs to be hammered home and repeated until it sinks in. People who read pop-sci magazines and websites, or who view Discovery Channel specials as "gospel" truth do science a disservice when they see next year's special and notice it says something different and decide that scientists don't know what they're talking about. It's like people who criticize the weatherman for getting the forecast wrong...they just don't understand what a forecast is.