You’re right that science doesn’t give guidance about morality. But I don’t think any of your examples show that “anti-science” people were right — only that some scientists have been wrong. Matt’s example is a good one (though apropos of the Boas case he could have added anti-Semitism to his list of hostilities).

Dave Roth is correct to distinguish the eugenics and racism issues (were these ever distinct?) from climate change. In this case, among others, the precautionary principle deserves more respect than it gets from the champions of cost-benefit analysis. It’s a flexible principle requiring judgment (rather than a rule, like CBA, based on a superficially objective algorithm that conceals judgments). In this it’s no different from most other practical judgments, especially the moral ones you correctly emphasize.

Moreover, the small sample size issue that you raise is specious. This issue is nothing new in daily life. E.g., all questions of political policy, and most decisions in business, are based on the need to make decisions in the face of new circumstances. Consequently, they rely more on Bayesian than frequentist foundations (or readers who are soi-pensant economists can use Frank Knight’s fuzzy distinction between risk and uncertainty if they prefer).

You were the guy who posted that terrific quote from Yes, Prime Minister, weren’t you? You seem to be forgetting it’s satire here.

This partly shows how hard this sort of thing is. Why this _might_ be true of a majority of researchers at the time, it certainly wasn’t the only respectable view. Franz Boas, for example, one of the founders of modern anthropology, was arguing quite explicitly at just this time that scientific racism was bunk. He may not have had the majority view, but he had a strong and important one. His view was made less influential for some time not for “scientific” reasons but more or less nakedly political ones- hatred of Germans and “leftists” by old WASP types in science, the academy, and politics at the time.

Take eugenics. You’re a policymaker at the turn of the century who believes the scientific “consensus” behind eugenics. If you act on this scientific “consensus” and sterilize a lot of people, and it is later revealed that the eugenics science is false, then you’ve done something enormously unjust and hurt a lot of people.

However, if you don’t adopt any policy measures in light of the science, and the science turns out to be true, then there doesn’t seem to be a huge amount of harm. I guess you’ve slightly delayed the evolution of the human race (or something; I’m not quite sure what eugenicists would say).

So in this case, it seems that policymakers should have required a much higher level of scientific certainty on the question of eugenics, since there are enormous harms if they act on the basis of this science and the science proves false, but much smaller harms if they don’t act on the science and it proves true. The consequences of acting and being wrong are much worse than the consequences of not acting and being wrong. So skepticism and caution seem justified.

But on climate change, the possible outcomes are quite different. If we act on climate change science and restrict emissions, and it turns out that the science is wrong, then we’ve slowed global growth by a few percentage points of GDP. That sucks, I guess.

But if we don’t act, and it turns out the science is right, well then we’ve got a huge disaster (if you believe the scientists’ projections).

So on climate change, the consequences of not acting and being wrong are much worse (at least so it seems to me) than acting and being wrong.

In light of this, I think policymakers should require less scientific certainty to take action than in, say, eugenics.

I don’t know what to say about your food pyramid example, since I can’t really speculate as to what harms were caused by adopting it in error, nor do I know what would’ve happened if we hadn’t adopted it. I think it’s safe to say, though, that the harms of adopting an erroneous food pyramid are probably much less than the harms of failing to act on climate science will be if that science turns out to be correct.

So you’re saying that Justice Butler was a lawless judicial activist who allowed his personal beliefs to influence his decisions?