[quickthrower2]

Thanks to you both for uncovering this rabbit hole. I found this https://www.lesswrong.com/posts/g28WWuaMLXNzAnR9v/rational-v... which seems to explain the difference and is in line with your vaccination example.

Although whether not vaccinating is rational I need to get my head around that as I’m quite biased on the subject but want to understand that more, otherwise I probably don’t understand the word rational.

[giantg2]

The example they gave was about the comparative value of being vaccinated vs not. Since the population is vaccinated above the herd immunity rate for the MMR vaccine, then there is a perception by the individual that there is little to no personal value to recieving it given that herd immunity protects them. So in their mind, the risk of an adverse event outweighs the risk of becoming infected. It is rational. Then the question is on whether it is reasonable. For someone with a high likelihood of an adverse event (such as from a prior dose or existing condition) then this is also reasonable. If they don't have an increased likelihood, then maybe it's not reasonable.

Of course if we fall below herd immunity, then the cost/benefit changes. Rational people who previously elected to not be vaccinated (without higher risk factors) would be likely to then elect to be vaccinated, in theory.

[icompetetowin]

Is this the article: https://aeon.co/essays/anti-vaccination-might-be-rational-bu...

Also this part stood out to me: "Sure, the risks of vaccination were low and the benefits to society were high. But if your kid is the rare person who experiences a severe side effect, the greater good no longer matters."

[giantg2]

Yeah, that's basically the part that I was thinking of when I was talking about individual benefit. Most people aren't getting vaccinated to protect society, but for their own benefit (as is human nature).