Deniers are not making scientific arguments. Scientific arguments require consistency, something which deniers make no pretence of striving for.
Plimer’s argument was that climate has changed in the past. Eg – climate has a high sensitivity. Monckton’s argument was that climate has a low sensitivity. I think the irony that the two [deniers] were arguing contradictory positions was lost on most of the audience.
In a sense, their combined approach perfectly encapsulates the way skeptic arguments are used to mislead. Layering argument upon argument, regardless of a lack of internal consistency, isn’t about furthering scientific understanding but proving the preconceived notion that humans can’t be causing global warming. Two skeptic arguments can contradict each other, even on the same debating stage, so long as the common enemy of man-made global warming is refuted.
To the deniers, consistency… or scientific evidence… or reality… isn’t important. What is important to them is to mislead… to twist the argument any way they can… to repeatedly bring up claims, regardless of whether the claims have long since been refuted… to use emotional or political arguments that have nothing to do with the science… to distort, cherry pick, and fabricate evidence in whatever way possible in their attempts to inject unwarranted doubt into the issue.
Why? Because they so want reality to conform to their pre-conceived political, ideological, or religious notions that they’re willing to use virtually any means at their disposal to keep their fortresses of self-delusion from tumbling down. I’ve seen that in action. I’ve heard deniers admit as much. What makes it worse is that they vigorously spread their misinformation, drag others down with them, and hobble any notion of having an intellectually honest discourse.
…because honesty… like consistency… like truth… is irrelevant to them.
And that makes them decidedly non-scientific.