While I think it is certainly fair to talk about the policies of other countries, I don't think just because another country has a different policy necessarily dictates that policy is better or worse.

Additionally, I think it's very easy to see something like "Denmark doesn't recommend the vaccines to anybody under 50" and conflate that it means that Denmark doesn't think vaccines were ever beneficial to people under the age of 50 (which is the leap in logic you often see on anti-vax sites). But that isn't the case. What was good health policy in 2021 is different from good health policy now, because we have way more information about the virus, better and more effective drug to treat it, new variants, etc.

Two things can be true at the same time: The vaccines are (on net) incredibly beneficial to people and the population as a whole, and yet at the present time there are certain specific populations of people whose optimal number of doses might be fewer than others.

> While I think it is certainly fair to talk about the policies of other countries, I don't think just because another country has a different policy necessarily dictates that policy is better or worse.

Sure. But if a person is aware that other countries have different policies, that gives them a legitimate reason to question whether the policy of their own country is correct. If a person looks into the matter, and decides not to follow the recommendations of their own government, because they think some other country's government is more likely to have got it right, such a person isn't necessarily being irrational/irresponsible/etc, nor would it necessarily be irrational/irresponsible/etc for them to share their conclusion with others.

> and conflate that it means that Denmark doesn't think vaccines were ever beneficial to people under the age of 50 (which is the leap in logic you often see on anti-vax sites)

Yes, many people do seem to conflate these two claims:

(1) "for healthy children and young people, the safety risk of additional doses of the vaccine currently outweighs the risk of COVID-19"

(2) "for healthy children and young people, the safety risk of any dose of the vaccine has always outweighed the risk of COVID-19"

While claim (1) is disputed, some highly respected medical experts agree with it; the same cannot be said for claim (2).

However, I think this conflation goes in both directions – some people who want to defend (2) do so by conflating it with (1); but conversely, some people attack (1) by conflating it with (2).

Some people can't distinguish reasonable scepticism about vaccinations from unreasonable scepticism.

Yeah, I agree completely.

It also is difficult position for health agencies to be in, because they want to make clear guidelines to prevent confusion, but there are gray areas. For example, it's completely possible that:

(a) The benefits outweigh the risks of a 4th shot for any age group

or

(b) The risks outweigh the benefits of a 4th shot for some or all age groups [not because the risk are high, but the benefits so low]

AFAIK, there aren't any super high quality studies anywhere in the world that have robust data on the 4th shot in particular for all age groups. So one health agency might guess one way, another health agency might guess another way. Reasonable people can disagree. The CDC got a little bit ahead of the science when they were initially recommending the 3rd shot, but in the long run it was proven to be a good gamble that no doubt saved thousands of lives. But now maybe that same logic is a mistake for the 4th shot.

But regardless of the CDC's recommendations, most people seem to have figured out the cost/benefit for themselves: The vast majority of people in the US have 2 shots, a little under half have the booster, and very few have the 4th shot. Most people probably have made the right choices for themselves given the various risks and benefits for them personally.

I trust that when I drive over a bridge it won't collapse.

But I cannot say I know that the bridge won't collapse.

Knowledge is a true and justified belief. But trust is not a justification - quite the opposite. If you had a justification, you wouldn't need trust.

Trust whomever you want, on whatever basis you want, but that's fundamentally not reason or rationality, it's just an argument from authority [1]. No statement becomes more true just because someone said it, regardless of who they are.

I'm not saying it's easy or even possible to do in practice. Science is insanely complex. But let's not confuse trust for rationality, not least of which because it brings to the fore the very real need for institutions that are worthy of our trust.

[1] https://en.wikipedia.org/wiki/Argument_from_authority

> Trust whomever you want, on whatever basis you want, but that's fundamentally not reason or rationality, it's just an argument from authority [1]. No statement becomes more true just because someone said it, regardless of who they are.

A statement can become more likely to be true just because someone said it, depending on the nature of the statement and the person making it. For example, my brother is an oncologist. If I had some health concern about cancer, I would certainly be asking for his opinion. His opinions on that topic are not guaranteed to be correct, but as an oncologist, they are significantly more likely to be correct than that of the average person.

One problem with the frequent popular invocation of claimed "fallacies", such as "argument from authority", is many of them are only strictly speaking fallacious when used as purely deductive arguments, but real world human reasoning isn't purely deductive, it involves a great deal of induction and abduction as well. There is nothing inherently wrong with an "argument from authority" as an inductive or abductive argument.

> Knowledge is a true and justified belief. But trust is not a justification - quite the opposite. If you had a justification, you wouldn't need trust.

One can estimate the conditional probability P(proposition X is true|agent A says that X is true) based on observations of what kinds of things agent A (or other significantly similar agents) has said in the past, and how many of them turned out to be true or false. You can then use that conditional probability estimate to inform your own decision as to how much credence to give to proposition X. That is both trust and justification.

> One problem with the frequent popular invocation of claimed "fallacies", such as "argument from authority", is many of them are only strictly speaking fallacious when used as purely deductive arguments,

There's a fallacy for that: https://en.wikipedia.org/wiki/Argument_from_fallacy

I was not aware of abduction before today, thank you!

I think we may agree in practice if not in theory. I did have the Hume-an problem of induction explicitly on my mind. It would be quite fair to say my epistemology is quite conservative.

Isn't your citing Wikipedia, in itself, an appeal to authority? Why should we accept Wikipedia as an authority on which arguments are fallacious and which are rational?

(Also, that wiki page mentions that many authors don't see it as a fallacy.)

I'm just citing it for the context of the argument both for and against appeal to authority being fallacious and irrational, not that Wikipedia is the final arbiter of what's rational or not. It's more to say that my position is not novel than anything else. Indeed, to be consistent I would need to say that I don't care how many authors do or don't see it as a fallacy :)

You could do some theoretical calculations about bridges yourself, inspect for cracks, and prove from first principles that the bridge is in fact safe; it's not some complicated biological process.

The change in policy by Denmark very likely comes down to the risk of overloading their ICU's with a naive covid population. When covid first arrived everyone was susceptible to covid and the long tail of poor outcomes was enough to plug up the hospitals (and primarily the ICU's).

Now, much of the population has become either naturally or through vaccination much less susceptible to poor outcomes from a covid infection, and this is especially true of younger people.

So the response to covid was never really about the health of the population as much as it was about the health of the hospitals. The risk to the hospitals is now much lower and therefore the reasonable vaccination effort has now changed.

> While I think it is certainly fair to talk about the policies of other countries, I don't think just because another country has a different policy necessarily dictates that policy is better or worse.

Other countries compared to who? Not everyone here is from the same country as you :)

I don't think anyone is making a value judgment based on where the policy is from.