Nothing is totally and completely settled for all time. There is always room for dissent and controversy. After all, truth is relative. We certainly don't want to live in a world that forbids disagreement.

In science, we go with a consensus from a system that has educational standards, professional institutions, peer-reviewed research and other safeguards. Still, this system of consensus has been known to be wrong occasionally, and I am certain it will be wrong again.

We can all think of several instances when the scientific consensus has been resisted by otherwise respected, even brilliant, practitioners in the field. Halton Arp and Fred Hoyle in my own field of astronomy come to mind. Controversy and disagreement is essential to science--and not all of these have occurred in the distant past.

By "denialist" I mean not just holding an opinion that conflicts with current orthodoxy, but to pursue that opinion because of purely philosophical or ideological or self-interest grounds. Creationists don't just question the evidence for evolution, they do so because it conflicts with their religious views. AGW denialists don't just reject the consensus of evidence and its interpretation, they do so for political and economic reasons. With these denialists, its all about conspiracy theories and supposed attacks on their religious or political or economic opinions.

I've always suspected that there is some other mechanism at work in evolution besides natural selection, that natural selection alone cannot explain the exquisite adaptation of organisms to their environment. I can't prove this, but my intuition screams it at me continuously. I just can't shake it, I just don't have the training or evidence to convince anyone else. But I do not attack Darwinism because it threatens my religion. Likewise, I can hypothesize that perhaps we are all mistaken about the nature of global warming, maybe we have gotten it wrong, either its existence, causes or eventual result. It's not very likely, but its not inconceivable. But I don't expect anyone to adopt that position simply because it threatens their opinions on economic policy--or their economic interest.

What leads me to believe that is what's going on with both creationism and AGW denialism is that the resistance is layered, its a defense-in-depth phenomenon with carefully prepared fallback positions which they can retreat to as the evidence and public opinion turns against them. These people aren't debating the science, they have selfish reasons for not wanting anyone else to believe it. And both of these anti-science positions are highly correlated with Conservative political thinking. You don't find a lot of atheists against Darwinism. And the opposition to AGW is mostly limited to the American Right.

The climate denialists first tell us there is no warming.

Then they claim its warming but just as part of some short term natural cycle. It will go away if we ignore it.

Then they concede its real, but not the human causes of it.

Then they claim its real and potentially severe, but we will adjust to it.

Then they tell us it is long term and severe, but due to natural causes over which we have no control.

Then they tell us we can do something about it, but its a waste of time because the Chinese will never go along with our plans and they will cheat.

And so on. They simply keep on bringing up objections to any actions which will affect them economically. They are not having a scientific debate, they are having a political one; they are protecting their economic interests. And when you point that out, they come up with all sorts of black helicopter, United Nations, Commie conspiracies and (my favorite) that it is a plot by climate scientists to get more grant money.

There is a satellite in a warehouse in Texas that could be launched right now to help resolve this issue once and for all, and Right wing Republicans in Congress have made sure it will not be deployed because they are afraid of what they and others might learn from it. They are terrified it might make their taxes go up, or regulate their industries more, and cast doubt on their political philosphy. This is an obscenity, and they, and all those who support them, are criminals.