Jared Diamond often points out that, sometimes, human history serves up parallel events that, in and of themselves, come close to allowing the kinds of confident comparisons the simpler sciences obtain via planned experiments.
We are now inside a special time-window where this point becomes pretty obvious and extra-important, aren’t we?
Consider, for example, the news on metropolitan air pollution levels.
Here is a telling depiction of what’s happened recently above Los Angeles:
It’s interesting — and, of course, macabre — that, at least in China, reduced air pollution might save as many lives as the pandemic ends.
Some fraction of that is due to reduced automobile use in Chinese cities.
And the point also applies, at least to some extent, in de-industrialized places like the United States, where wall-to-wall cars and trucks have their all-too-obvious, yet still thoroughly unmentionable, mortality effects.