Today’s major issues manifest that we live in a world of “ontological” uncertainty. Nobody can predict (let alone know!) how Brexit will unfold; whether the US-China trade war will escalate or not; if the Yellow Jackets movement will fade away; whether climate change will accelerate beyond our wildest fears… It is startling (but not infrequent) to hear decision makers and experts directly involved in such issues confess: “I simply don’t know…” In such circumstances, it’s hardly surprising that investors lack firm convictions and strong bouts of market volatility ensue.

Or market bubbles! The fact that wellness is so pervasive and often so hard to define makes it prone to all sorts of excesses and bubbles. Fashions for this and that come and go! One noticeable current example is the craze for celery juice. From October of last year to January of this year, celery juice sales have gone up 454 percent in the US—a most unusual trend for a so-called “superfood” that tastes of water and sells at four times the rate of kale juice.

What’s the trick? As is too often the case, it boils down to one person who makes dubious scientific assertions that get hyped on social media. In this particular case: Anthony William, the man behind Medical Medium, a NYT best-selling author and contributor to GOOP, who describes himself as the “originator of the global celery juice movement.” In the absence of randomized controlled trials, no reputable nutritionist or other scientist would corroborate William’s assertion that “people are healing” thanks to celery juice, but this is not the point. There is no doubt celery (like almost all other vegetables) is good for us and we can enjoy its benefits by simply eating it (rather than juicing it and making it costlier), but the point is this: Crazes like this one can give wellness a bad name.