Assorted Links

Thanks to Michael Bowerman.

Assorted Links

Thanks to Mark Griffiths.

More Anti-Science

Professional scientists mostly ignore the slogans (e.g., “absence of evidence isn’t evidence of absence”) I discussed in my previous post. For example, the professional-scientific conclusion that smoking causes lung cancer came mostly from correlations. This conclusion was criticized, sure, but not by saying “correlation does not equal causation”.

Professional scientists have a much worse problem, which is that they criticize much more easily and fluently than they praise. (Marginal Revolution is an excellent blog partly because it doesn’t suffer from this.) This can be depressing (lots of work is underappreciated), exciting (anyone who sees this has a big advantage), or merely amusing, as in this example to which Stephen Marsh drew my attention:

I just returned from the MS4 conference. It is the fourth year that a group of philosophers of science have gathered to try to tease apart the implications of computer simulation in science. . . .Several presentations gave harsh criticism of climate science models. Bayesian tools (a statistical technique) were given some especially harsh criticisms. Everyone agreed the models were problematic in some sense or another. That the results were subject to all kinds of errors and suspicions, and there were substantially difficult difficulties to sort out. . . . Despite this, everyone concurs the models are robust . . . No one disagreed that the planet was warming.

The poor ability of professional scientists to praise means that comparison of A and B (two theories, say, or two experiments) mainly consists of comparing how much A and B have been criticized. How much A and B would have been praised, had scientists been better at praise, is unknown. This is a very poor way to compare stuff. Inability to praise also means that there is too much criticism. In my experience, scientists have trouble separating serious criticisms from trivial ones. For example, that climate-change models haven’t been shown to predict correctly is a serious criticism not emphasized enough (e.g., at the MS4 conference).

Life Imitates Art: Climate-Change Edition

In a previous post I wrote about one of the silliest letters ever signed by a group of very smart people. At the end of my comment, I wrote:

If a letter from 100 United States Senators was full of spelling and grammar errors, would you trust it?

The letter was written by Peter Gleick, a MacArthur Prize winner. In a follow-up essay in the Huffington Post, he twice called ice floes “ice flows” (“there really are polar bears on ice flows”). Who says life doesn’t imitate art?

Distinguished Scienists Fail to Think for Themselves

A long list of National Academy of Science members, including several Nobel Prize winners, have published a letter in Science supporting the idea that humans have caused/will cause serious global warming. The letter is striking in several ways — how preachy it is, how it overstates its case, how it fails to provide evidence, and how it ignores the main arguments of skeptics (at least, intelligent skeptics).

It begins:

All citizens should understand some basic scientific facts. There is always some uncertainty associated with scientific conclusions; science never absolutely proves anything. When someone says that society should wait until scientists are absolutely certain before taking any action, it is the same as saying society should never take action.

“Citizens”, huh? This might interest third-graders; if they think that the brighter skeptics or most readers of Science don’t know these “basic scientific facts” they are mistaken.

The letter goes on to claim that the idea that humans are seriously warming the planet is as well established — at least, in the same category of firmly-established theories — as the conclusion that “today’s organisms evolved from ones living in the past”. That is an overstatement.

And the letter ends with hand-waving. In place of evidence that supports what they claim, they simply repeat the claims in detail (e.g., “Natural causes always play a role in changing Earth’s climate, but are now being overwhelmed by human-induced changes”).

The letter is unintentionally revealing. Here’s what I would consider reasonable evidence for serious human-generated global warming:

  1. Temperature higher now than in the past.
  2. Temperature increasing at a higher rate now than in the past.
  3. Good (= verified) model shows serious human-generated warming.

No. 1 isn’t clearly true; the Medieval Warm Period appears to be as warm as now. (Mann et al. understood this point; they tried to diminish the Medieval Warm Period.) No. 2 isn’t clearly true. For example, the 1930s may have been as warm as recent decades. No. 3 isn’t true. Models such as Hansen’s haven’t been shown to predict correctly. There’s no reason to take them seriously.

So No. 3 is off the table (current models are untrustworthy). That leaves Nos. 1 and 2, the failure of which to be clearly true points in the direction of no serious human-generated warming. If a theory makes two predictions, both of which appear wrong, it would be wise to start doubting the theory rather than lecture the rest of us on “basic scientific facts”.

This line of reasoning (ask whether the humans-have-caused-serious-warming idea makes correct predictions) isn’t complicated or obscure but does require you think for yourself rather than accept what you’re told. Apparently no one in this long list of distinguished scientists has done so.

If a letter from 100 United States Senators was full of spelling and grammar errors, would you trust it? Well, no . . . and you might wonder about a world with such a poorly-educated ruling class.