For a full year now a courageous, clear, and deeply principled voice against Covid-19 lockdowns has been that of EconLog’s David Henderson. See, for example, here  and here . And yesterday at EconLog  (as I noted here ), David rightly scolded me for carelessly giving a full three cheers (rather than a lower number) to Florida governor Ron DeSantis for resisting vaccine passports.
At David’s EconLog post yesterday, commenter Michael Sandifer put to David the following questions:
Is there any level of risk for which you’d have government mandate vaccination and providing paperwork thereof? If we had a pandemic killing 1/3 of people infected, for example, and it’s highly contagious?
These questions are perfectly understandable and fair. But encountering them brought to mind one of the most important lessons that I learned in law school – a lesson that I described in a reply to Mr. Sandifer, and that I share here (with very slight modification):
I remember well my very first day of law-school classes. It was late August of 1989. My great contracts professor, Bob Scott, announced that he doesn’t want to hear hypotheticals. Later that same day, my great torts professor, Saul Levmore, announced that he doesn’t want to hear hypotheticals. I heard the same prohibition on hypotheticals from some other professors during my entire three years in law school.
I recall being disappointed. “Hypotheticals are not only fun, they’re also useful,” I thought to myself. “Economists and, especially, philosophers use them all the time.” But I soon grasped the wisdom of avoiding hypotheticals in law school – which is this:
Law, especially in the Anglo-American tradition, grows out of lived experience. And lived experience is too often filled with too many surprises and complexities for hypotheticals to take adequate cognizance of.
Hypotheticals have their place, of course – and the questions posed here to David about a hypothetical situation are reasonable. But everyone should be aware of, and wary of, the unseen danger lurking within hypotheticals. Precisely because the ‘facts’ in hypotheticals are posited ex nihilo, these ‘facts’ are divorced from other facts that, in the real world, might be so relevant as to change the assessment of the real-world situation from the assessment of the hypothetical.
Another danger of hypotheticals springs from the human-imagination’s great fertility: hypotheticals are too easy to imagine. And once something is imagined, it’s too easy to lose track of just how likely is the hypothetical to come true in reality. Ability to imagine some possibility is not an ability to judge how plausible is that hypothetical; much less is it an ability to judge how probable it is.
By avoiding hypotheticals in legal instruction, good law professors keep their students’ focused on conflicts and situations that actually occurred, thus avoiding possible distortions in thinking that might well arise when students have their heads full of hypotheticals.
If people were more wary of hypotheticals, one great benefit would be far less infatuation with the so-called “precautionary principle” – a dangerous idea that is rooted in hypotheticals.