‘Critical mass’ is a classic case of wandering jargon: an expression that started off with a precise meaning in a technical field (in nuclear physics, it’s the amount of fissile material needed to trigger a chain reaction), but then went wandering abroad, roaming into all kinds of unsavory places and picking up dodgy friends and bad habits, until it no longer had any dignity left. This is the sad life story behind most of the goofiest words and phrases in our professional vocabularies.
In the early stage of its ramblings outside the physics lab, “critical mass” found itself hanging out with the sociologists — a perfectly respectable crowd, but already a long way from home. The sociologists found the phrase handy for at least a semi-technical purpose: to describe the moment when enough people are doing something so that other people start to feel compelled to do it too. One person at a bar starts to sing, and the other customers roll their eyes.
Two or three people sing together, and maybe everyone else thinks it’s quaint. Ten or 15 people start crooning, and presto, it’s a singalong. You get the idea. It’s not nearly as precise a concept as nuclear critical mass, but it has a meaning and some practical use.
But then all hell broke loose. Soon, everything that grew big enough to make anything else happen was being called “critical mass.” Every required minimum — every parliamentary quorum, every fourth hand at bridge, every second lump of sugar, every pile of wood big enough to start a campfire — suddenly put on a lab coat and went strutting about calling itself “critical mass.”
Today, “critical mass” has become a close cousin of “scale.” Both expressions mean “something big enough to do something important,” but that’s about it. How big? How important? Big compared to what? Who knows? Even if we assume, out of an abundance of kindness, that a person who uses these expressions actually has a specific meaning in mind, the rest of us still have no way of knowing what that neat, well-thought-out meaning might be. And that’s because we’ve heard the same concept bandied about by every ticket scalper and hot-dog vendor on Broadway (“How many tickets have you got?” “How much sauerkraut do you want?” “Oh, a critical mass!”). There’s simply no way to know what particular “scale” or “mass” or “scope” somebody has in mind, or what (if anything) might make it “critical.” By now, I’m sorry to say, there’s every good reason to suspect that people who use these words may not actually have any particular size or scale or mass in mind at all. As far as meaning is concerned, the phrase has reached the stage of critical void.