Dennis Mangan's dangerous ideas

Mangan links to an article by Richard Thaler at The Edge which asks,
The flat earth and geocentric world are examples of wrong scientific beliefs that were held for long periods. Can you name your favorite example and for extra credit why it was believed to be true?

Mangan provides excerpts from the following Edge contributors:
Greg Cochran answers:

I would guess that most basic anthropological doctrine is false — for example. the 'psychic unity of mankind'. but then most practitioners don't really pretend to do science.

The doctrine is, of course, gnostic in that it presumes a mind/body dichotomy, a non-corporeal, uniform human 'essence' which justifies equality of outcomes. Edge contributor Judith Harris takes a related stab:
The apple doesn't fall far from the tree. In other words, people tend to resemble their parents. They resemble their parents not only in physical appearance but also, to some degree, in psychological characteristics.

The question is: Why? Two competing answers have been offered: nature (the genes that people inherit from their parents) and nurture (the way their parents brought them up). Neither of these extreme positions stood up to scrutiny and they eventually gave way to a compromise solution: nature + nurture. Half nature, half nurture. This compromise is now an accepted belief, widely held by scientists and nonscientists alike.

But the compromise solution is wrong, too. Genes do indeed make people turn out something like their parents, but the way their parents brought them up does not. So nature + nurture is wrong: it's nature + something else.
As one of Mangan's commenters points out, we know that brain development is greatly affected by early sensory inputs. Abandoned animals and children are mentally stunted. However, we also know that different people respond to the same environment in different ways, so Harris's hypothesis seems to have some merit.

Mangan then lists his own examples of currently held beliefs he predicts will be proven erroneous.
I haven't read all the contributors' answers, but I'll throw out the lipid hypothesis (or cholesterol hypothesis) of heart disease, although the belief is still widely held by many. I'm certain that it's wrong, and put my money where my mouth is by living accordingly.

I'm less certain about HIV as a cause of AIDS, but I do believe that the theory will have to be at least seriously modified.

Another one: exposure to solar radiation is unhealthy, and that one should avoid it to prevent cancer. Still widely held.

The theory of anthropogenic global warming: nothing but a fad.

To the extent that economics is a science - that is, to not a great extent - Keynesian economic theory is wrong, the Austrians are right.
This strikes me as a pretty good list. Low carb has withstood everything the USDA has thrown at it. AIDS appears 'sticky' to unhygienic practices that put a heavy load on the immune system, and people who do not engage in those practices remain resistant to HIV despite dire warnings that 'we all are at risk.' Has HIV actually been isolated?

With respect to solar radiation/skin cancer, I think Mangan is overlooking the pretty obvious evolutionary adaptation of melanin content.

Global warming: How can a compound, CO2, which comprises 0.039% of the atmosphere and which retains less heat than more abundant water vapor be responsible for global warming? We are told that the glaciers and polar ice caps are melting which means they are absorbing heat, like a cold turkey placed in a hot oven. Do the numbers balance? Is there that much 'excess' heat, and again, how can it be due to a trace atmospheric compound? The AGW hypothesis reminds me of the astrologer's fallacy: the movements of celestial bodies light-years away are believed to exert more influence on human development than, say, the actions of the obstetrician. Why is CO2 and not solar activity or urbanization the object of inquiry?

Keynesian theory: In 1990, the world saw the essential, inevitable failure of Marxism. Keynesian policies are not far behind. Deficit spending, money printing, suppression of interest rates, all efforts to 'prime the pump' during recessions are, at bottom, just loans taken out against future productivity. Eventually you run out of future.

The larger social trend that merits comment is how the alleged anti-science of the Roman Catholic theocracy has been adopted by the secular humanist establishment.


Dirichlet said…
In the longest of terms, my money is on liberal democracy. Currently, the secular PC elites tell us that democracy is either the apex of human government or --from the ones that have a bit of decency-- the "least worst" of political systems. But the more one examines history with a critical eye, the more it seems like this system is plagued with instability, inefficiency and the tendency towards self-destruction through liberalism and the welfare state.

Some Austrians, like HH Hoppe, argue that democracy is even inferior to monarchy!