But they speak with the voice of an authority, without ever stating a clear point or conclusion, so that the viewer leaves with a vague sense of disillusionment with their former position on the subject, but lacking any substantial evidence to completely abandon it. I love the show, but in this case, I don't think they're clear enough. What is the data supporting global warming or contradicting it? and not from some washed up weather person.

Carl Sagan, and more recent figures like Richard Dawkins and Neil Degrasse Tyson, were authorities. They are review writers and go-to people on the things they propose. I trust their judgments because science permeates their words. Where Penn goes on a cursing tirade that evokes our intellect and our emotion, popular scientists temper their words with scientific reservation. Current scientific events are only current because they are uncertain and important, hence why people feel so uncomfortable about them. Penn (I would say Teller, as well, but he doesn't speak) just doesn't have the subtlety or the authority to tromp about with such a lack of authority speaking with authority on numerous topics. Even the authorities whom Penn and Teller garner for the shows are dubious at times.

That's all I'm saying.