1/ Suppose you create a situation where people can't challenge or doubt X without significant cost. Can we take X seriously? Or: can we be justified in believing X?

2/ John Stuart Mill wrote: "If even the Newtonian philosophy were not permitted to be questioned, mankind could not feel as complete assurance of its truth as they now do."

Now, Newtonian physics at the time was the gold standard, confirmed through countless experiments.

3/ But if you create a situation where people can't challenge it, then if there is a problem with the theory, it won't surface.

As it turns out, Einstein later showed that Newtonian physics is only true in approximation.

4/ Take the extreme case. Suppose the Dictator says, "any economist who criticizes the economic policy gets sent to the gulag."

In such a case, can we trust said economists? Of course they will give all sorts of reasons why the economy is doing superb.

5/ But their reasoning must be taken with a mountain of salt.

In a sense then, our knowledge is socially achieved. If we are to be confident in something, the social incentives have to be right.

6/ This is why we can be fairly confident with respect to physics, chemistry, geology, etc.

There, the incentives are about as good as they can be. Nobody gets flak for working on the Higgs boson or finding a new polymer.

7/ But there are other domains -- particularly those relevant to policy and morality -- where things might not be as rosy.

@GlennLoury puts it thus:

8/ If knowledge is a common resource, there is an associated tragedy of the commons. As air pollution degrades the atmospheric commons, I argue in the book that _social pressure_ degrades the epistemic commons. https://www.amazon.com/Why-Its-Speak-Your-Mind/dp/0367141728

9/ Now, it's in general bad to free ride. It's bad to let everyone else do the dishes, worry about pollution, littering, etc.

Free riding in the epistemic context is never challenging an opinion when faced with social pressure not to do so.

10/ A free rider in this sense is a conformist -- saying whatever gets them ahead in their social circle. [See @CassSunstein's excellent book "Conformity" for more on this.]

11/ A well-maintained epistemic commons benefits humanity in general (just like clean air) but the costs of maintenance are concentrated. Hence the tragedy.

The only way to solve it involves individuals being willing to speak their minds.

12/ And, furthermore, creating social norms where costs for dissent are lowered. Much work to be done in this regard!