http://www.space.com/news/hawking_rebuttal_011016.html

A soft scientist named BennyPeiser has just called a hard scientist named StephenHawking a nasty name in the press. Hawking is concerned that humanity is facing a tough time, biologically, over the next thousand years, and may not survive if it doesn't establish colonies in more than one place. Peiser asserts that the planet has never looked more hospitable, and that Hawking is suffering from a mental condition that skews his rationality.

Who's full of it on this one? 

''Oh, Peiser, even if he's right about the world. Anyone who diagnoses mental conditions from someone's reported comments in newspapers is definitely full of it.''

Where does he do that?

''Follow the link above. With daily news about the increasing effects of GlobalWarming, new discoveries of common household solvents increasing the ozone hole, not to mention species extinctions proceeding at 10,000 times the rate of a century ago, Peiser appears quite nutty. Some kind of PanzaIsm, I guess.''

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''background reading ...''

* http://www.newscientist.com/news/news.jsp?id=ns99991438 -- ozone hole
* GlobalSpeciesExtinctions

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It certainly appears that both Hawking and Peiser are speaking outside of their areas of expertise and, hard scientist or not, there is really no reason to give extra weight to the utterances of anyone speaking outside of their areas of expertise. (If anyone doubts this, RichardPosner's recent book on public intellectuals supplies numerous examples.)

Peiser certainly loses points for psychologizing Hawking, but that doesn't make his basic position invalid (or valid!) or nutty. GlobalWarming, the ozone layer, and species extinctions are all things to worry about, but the key question here it seems to me is how we, the human species, should divide our efforts and resources among the three areas of
* Fighting GlobalWarming, etc.,
* Researching and building colony ships, and
* Enjoying a happy life in the present.
[If you don't think the third area is important, you are free to donate all of your money to fund research in the first two areas.]

I don't pretend to know the correct answer to this question, and in fact it seems clear that different people are going to have different answers depending on the risk that they calculate GlobalWarming etc. pose to the human species as a function of the resources spent to fight them, the *variance* (error bars) of their estimate of that risk, the expected chance of success of spawning another self-sustaining off-planet colony of humans in a given period of time as a function of the resources spent to achieve it, the variance of that estimate, the weight they give to the happiness of future generations relative to that of their own generation, and their own general degree of risk adverseness.

What I do know is that anyone who pretends the answer is simple or obvious is, in the words of ThePrincessBride, "selling you something". -- ThomasColthurst

''I followed the link above, and I don't see where Peiser claimed to diagnose any mental condition in Hawking. What did I miss?''

Wow. You are right - nowhere in the linked article does Peiser do this. The anonymous contributor of the italicized comments in the first section successfully pulled off one of the classic JediMindTrick''''''s against me. (It's the one that I believe psychologists call "priming".) Thanks for catching this. -- ThomasColthurst

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He doesn't call him nutty, but I think that this quote clearly implies it:
	 :	"Stephen Hawking's predictions of terrestrial doom have become increasingly wide-ranging and unreasonable in recent years," Peiser writes. "They also manifest a certain arbitrariness in his choice of end-time scenarios."

''Well, if Hawking has been predicting the end of the world and that extraterrestrial colonies are the solution to this, then I agree that he's completely nutty. Resource depletion is a serious issue, but I don't see extraterrestrial colonies as a solution to it.''