I have an idea I'd like to discuss that might perhaps be good enough for my first top-level post once it's developed a bit further, but I'd first like to ask if someone maybe knows of any previous posts in which something similar was discussed. So I'll post a rough outline here as a request for comments.

It's about a potential source of severe and hard to detect biases about all sorts of topics where the following conditions apply:

1. It's a matter of practical interest to most people, where it's basically impossible not to have an opinion. So people have strong opinions, and you basically can't avoid forming one too.

2. The available hard scientific evidence doesn't say much about the subject, so one must instead make do with sparse, incomplete, disorganized, and non-obvious pieces of rational evidence. This of course means that even small and subtle biases can wreak havoc.

3. Factual and normative issues are heavily entangled in this topic. By this I mean that people care deeply about the normative issues involved, and view the related factual issues through the heavily biasing lens of whether they lead to consequentialist arguments for or against their favored normative beliefs. (Of course, lots of folks won't have their logic straight, so it's enough that a particular factual belief is perceived to correlate with a popular or unpopular normative belief to be a subject of widespread bias in one or the other direction.)

4. Finally, the prevailing opinions on the subject have changed heavily through history, both factually and normatively, and people view the normative beliefs prevailing today as enlightened progress over terrible evils of the past.

These conditions of course apply to lots of stuff related to politics, social issues, etc. Now, the exact bias mechanism I have in mind is as follows.

As per the assumptions (3) and (4), people are aware (more or less) that the opinions on the subject in question were very different in the past, both factually and normatively. Since they support the present norms, they'll of course believe that the past norms were evil and good riddance to them. They'll chalk that one up for "progress" -- in their minds, the same vaguely defined historical process that brought us science and prosperity in place of superstition and squalor, improvements that are impossible to deny, has also brought us good and enlightened normative beliefs on this issue instead of the former unfair, harmful, or just plain disturbing norms. However, since the area in question, as we've assumed under (2), is not amenable to a hard-scientific straightening out of facts from bullshit, it's not at all clear that the presently prevailing factual beliefs are not severely biased. In fact, regardless of what normative beliefs one has about it, there is no rational reason at all to believe that the factual beliefs about the topic did not in fact become more remote from reality compared to some point in the past.

And now we get to the troublesome part where the biases get their ironclad armor: arguing that we've actually been increasingly deluding ourselves factually about some such topic ever since some point in the past, no matter how good the argument and evidence presented, will as per (3) and (4) automatically be perceived as an attack on the cherished contemporary normative beliefs by a reactionary moral monster. This will be true in the sense that updating the modern false factual beliefs will undermine some widely accepted consequentialist arguments for the modern normative beliefs -- but regardless, even if one is still committed to these normative beliefs, they should be defended using logic and truth, not bias and falsity. Moreover, since both the normative and factual historical changes in prevailing beliefs have been chalked up to "progress," the argument will be seen as an attack on progress as such, including its parts that have brought indisputable enrichment and true insight, and is thus seen as sacrilege against all the associated high-status ideas, institutions, and people.

To put it as briefly as possible, the bias is against valid arguments presenting evidence that certain historical changes in factual beliefs have been away from reality and towards greater delusions and biases. It rests on:

• a biased moralistic reaction to what is perceived as an attack on the modern cherished normative beliefs, and

• a bias in favor of ideas (and the associated institutions and individuals, both contemporary and historical) that enjoy the high status awarded by being a contributor to "progress."

What should be emphasized is that this results in factual beliefs being wrong and biased, and the normative beliefs, whatever one's opinion about their ultimate validity, owing lots of their support to factually flawed consequentialist arguments.

Does this make any sense? It's just a quick dump of some three-quarters-baked ideas, but I'd like to see if it can be refined and expanded into an article.