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Re: [Phys-L] "Climate science is not settled"

Thanks, John, for your work in explaining what should have been more
obvious to more of us.
Bill Norwood
On Oct 4, 2014 1:13 AM, "John Denker" <> wrote:

Let's talk a little more about what it means for something
to be "settled".

The poster child for this is the law about driving on the
"correct" side of the road. Not all that long ago, in most
places there was no such law. That was fine as long as
traffic was very light. Then one day somebody noticed
that traffic was heavier than it used to be, and there
were quite a few roads with two or more lanes. They said
hey, if we imposed some discipline there would be a lot
fewer crashes.

Initially, the decision was made independently in each
city, at various times. In each case, there were three
a) Require everybody to drive on the right.
b) Require everybody to drive on the left.
c) The null option: Leave it unregulated.

There is no basis in physics for preferring left over
right. The relevant fundamental laws are symmetrical.
Coriolis forces due to the earth's rotation are negligible.
Most people are right-handed, but that doesn't prevent
them from driving on one side or the other. Historically,
different cities made different choices, with no discernible
advantage either way.

My point is simple: The as soon as the decision is made,
the matter is settled. It is settled in the sense that
even if you don't like the decision, it is easier to live
with it than to protest it. There is tremendous value in
having /some/ non-null regulation, and this outweighs any
advantage you might get from protesting.

It would be the height of idiocy to say that "the science
isn't settled" so therefore we must continue with no
regulation. Even if we did think that physics would
eventually give us a reason to prefer (a) over (b) or vice
versa, the advantage would be so small as to be not worth
waiting for. There is value in having a "settled" non-null
regulation /now/, whether it is based on physics or not.

So: Waiting be bad public policy. Blaming the wait on
science would be just ridiculous. For one thing, it's
wrong as to the science, insofar as even within physics we
know about spontaneous symmetry breaking, where the symmetry
of the solution is lower than the symmetry of the equation
being solved. Physicists make arbitrary decisions all the
time. Lots of things are just not worth micro-optimizing.


Things get weird when policy-makers and decision-makers
try to keep scientists at arm's length. "You give me
the raw facts, and I'll make the decisions". That is
an artificial separation, not natural to science, and
those who impose such a separation bear 100% of the blame
when it goes wrong. Just because certain policy-makers
are stupid about science does not mean that scientists
are stupid about policy.

The climate science "debate" is in this category.

Here is another analogy: In baseball, the umpire has
to call balls and strikes. There will always be marginal
cases, where the call could have gone either way. Still
the call has to be made. There is value in having a
settled non-null call.

Pretending that a marginal call is "not scientific"
betrays a fundamental non-understanding of science.
Real science does not provide -- or even pretend
to provide -- complete certainty. Instead, science
provides good ways to make decisions, even when
the data is imperfect.

Now suppose a baseball umpire hires a "scientist" to
measure the trajectory of the pitch. The "scientist"
determines that the pitch was outside the strike zone by
25 ± 2 cm. The "scientist" and all 50,000 spectators
know the pitch was outside, and know that the batter
never took the bat off his shoulder ... yet the umpire
refuses to call it a ball, claiming that the science
is "not settled".

Maybe video review would reduce the uncertainty, so that
the ball was outside by 25 ± 1 cm ... but why bother?

If you want the scientist to make the call, he can
certainly do that. It's an easy call. On the other
side of the same coin, if the umpire won't let the
scientist make the call, the umpire has to do it. That's
the umpire's job for crying out loud. It's just ridiculous
to forbid the scientist from making the call and then blame
him for not making it.

Then we find out that the umpire is financially beholden
to one pitcher, and only complains that the science is
"not settled" when it benefits that particular pitcher.
It's a scandal. Blaming the "scientist" just adds insult
to injury.

The root cause of the conflict is the fact that it is
easier and more cost-effective to buy politicians than
to buy scientists. We are seeing the same tactics (and
in some cases the same bad actors) as we saw claiming
that the tobacco/cancer science was "not settled".
Also the environmental-lead/brain-damage science was
"not settled".

Scientists know about spontaneous symmetry breaking, and
they know about economics. They know that sometimes it
pays to wait for more data, but OTOH sometimes it pays
to make a "settled" decision based on imperfect data.
A scientist can call balls and strikes even when it's
a close call ... and it's even easier to make the call
when it's not close, which is where things stand with
climate policy.

So don't tell me climate science is not settled. Such a
statement is either untrue or irrelevant or both. Mostly
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