sits on a committee vs. sits in a committee

[GoodTaste]

Which is correct? "Sit on" or "sit in"?

"Sit on" has two definitions:
1.to delay dealing with something
2.to prevent someone from saying or doing anything more, especially by severely criticizing them

"Sit in" has two too:
1) to be present in a meeting or class, watching it but not taking part in it.
2) to go as a group into a public building and refuse to leave or to allow normal activities to continue there until a situation that you are complaining about is changed.

It seems "sit in" 1) okay here. But "sit on" could be the combination of "sit" and "on" rather than a set phrase. In that case, "sit on" means "be a member of". I am not sure.


======================
What’s missing, say Topol and other scientists, are details about the nature of the infections the vaccine can protect against — whether they are mostly mild cases of COVID-19 or also include significant numbers of moderate and severe cases. “I want to know the spectrum of disease that the vaccine prevents,” says Paul Offit, a vaccine scientist at the University of Pennsylvania who sits on a US Food and Drug Administration advisory committee that is set to evaluate the vaccine next month. “You’d like to see at least a handful of cases of severe disease in the placebo group,” he adds, because it would suggest that the vaccine has the potential to prevent such cases.

Source: Naure 09 NOVEMBER 2020
https://www.nature.com/articles/d41586-020-03166-8

 

[emsr2d2]

Simple answer: we always sit on a committee.

 

[GoesStation]

In the quotation, "sits on" means "is a member of" or "serves on".

 

[jutfrank]

There is a major problem with your question—it is incorrect to say that sit on and sit in each have two definitions. In fact, it's not a useful way of thinking to suppose that these strings have any definitions. What you need to focus on is the different meanings of the prepositions in/on and how they make sense in a given context.

The correct preposition here is on, since, as emsr2d2 says, the prepositional object is a committee. In other words, only on makes sense in this context. The idea is that Mr Offit is a member of the committee.

 

[Rover_KE]

Simple answer: we always sit on a committee.

Right—Paul Offit was on it.:mrgreen:

 

[jutfrank]

Let's presume he hasn't come off it.