But population doesn't (in my opinion) determine importance. For example, the capital is a very important city even if not the most populous.

That said, I'm basically questioning an off-the-cuff quote made by a friend of someone who was in the elevator. The speaker should be forgiven for being imprecise…

> But population doesn't (in my opinion) determine importance. For example, the capital is a very important city even if not the most populous.

It goes the other way. Importance determines population. If the capital is not populous, that reflects the fact that the capital isn't especially important.

But assuming you're in a more or less steady state, that effect has already happened, so it's perfectly valid to just assume that importance and population are tightly correlated. The directionality doesn't really matter to the result.

> Importance determines population.

Does it though? You still have provided no supporting arguments for that. People live in places for reasons beyond importance. In fact, "importance" really isn't a factor people consider when they decide to live somewhere at all really in my experience.

> For example, the capital is a very important city even if not the most populous.

> and either San Francisco or Los Angeles (or both) also rank above Chicago

Wouldn't it be Sacramento in this case, as the capital but not most populous city? The most important city is a combination of multiple factors: size, economic or political power, and probably some more (like cultural).

No, Sacramento is pretty insignificant in terms of population and economic power compared to SF and LA (and cultural aspects). Political power is also tied to population - LA and SF decide who sits in power in Sacramento. DC is an exception because it draws lobbyists and politicians there; state capitals usually don't.

That was my point, just being a capital doesn't say much and it's not a real factor when it comes to the importance of a city.

In this case it does. The author used population as criteria for importance. Which is fine. You might have a different criteria.

> The author used population as criteria for importance.

There's no evidence for that anywhere, nor is this the author. This is a quote from a friend of someone in the elevator and there's no given criteria, so we can only speculate.

This is a person being quoted about the event, not the paper (local or WaPo). I don't think there's really much rhyme or reason here, I'd bet it's just what the person casually thinks about Chicago's importance.