[DVaut1]

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You know my old college had some really old books in the basement. One was titled the Dynamics of Ether or something to that effect from the turn of the century. An entire book about how ether was everywhere and filled all of space. People really believed that back then, it was "consensus" for awhile.

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Scientific opinion has been wrong many times

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There points are by and large irrelevant, and miss the mark by a mile.

But this does introduce one of the favorite fallacious arguments of the creationist and global warming denialist camps: "scientific consensus was once X, but X was discovered to be wrong, therefore scientific consensus is not to be trusted."

The scientific method is such that it corrects for knowledge that was previously in error. The reason why we discovered what was formerly scientific consensus to be wrong is precisely the same reason why it's most reasonable to believe the current scientific consensus is correct. Claims which rest upon scientific consensus as being infallible are almost by definition invalid, but similarly, the very notion of epistemology demands that we respect scientific consensus as being the closest to the normative truth.

In other words, pointing out scientists or scientific consensus has been wrong in the past says absolutely nothing, repeat nothing, about the validity of current scientific consensus. This should be patently obvious to everyone, but since we see the "lolz but everyone once thought the Earth was the center of the universe, and people got the plague from miasmas, so how can we trust anything people say about global warming and/or evolution" argument so frequently, apparently it's not quite that obvious to some.

If you insist on relying on this argument ("lolz but everyone once thought the Earth was the center of the solar system, they were wrong, therefore scientific consensus needs to be doubted"), then surely you're not certain about the validity of the theory of gravity, or germ theory, or heliocentrism, since hey, the consensus has been wrong before. That's all we need to know in order to cast doubt, right?

The obvious response to this is by the various "consensus is wrong camps" is something along the lines of: "but wait, gravity, germ theory, and heliocentrism have been sufficiently demonstrated empirically". Bravo. At least we finally get to the crux of the real argument, as opposed to just fallaciously pointing out that people have been wrong in the past in some kind of strained attempt to discredit the current consensus.

Put differently, if the consensus in the HSNL forum was that PokerStars had the softest games at mid-high stakes NL, would "but everyone once thought the center of the solar system was the Earth" be a legitimate reason to believe PokerStars *doesn't* have the softest mid-high stakes NL games? It's 'legitimate' in that there's likely no way to be certain which site has the softest games, but the consensus in HSNL is likely to be right anyway, even if categorical certainty doesn't exist, and pointing out the popularity of geocentrism six centuries ago does absolutely nothing to change that.