Over at Pharyngula, Chris Clarke challenges those in the chemical know on their use of "dihydrogen monoxide" jokes. He writes:

Doing what I do for a living, I often find myself reading things on Facebook, Twitter, or those increasingly archaic sites called “blogs” in which the writer expresses concern about industrial effluent in our air, water, consumer products or food. Sometimes the concerns are well-founded, as in the example of pipeline breaks releasing volatile organic chemicals into your backyard. Sometimes, as in the case of concern over chemtrails or toxic vaccines, the concerns are ill-informed and spurious. And often enough, the educational system in the United States being the way it’s been since the Reagan administration, those concerns are couched in terms that would not be used by a person with a solid grounding in science. People sometimes miss the point of dose-dependency, of acute versus chronic exposure, of the difference between parts per million and parts per trillion. Sometimes their unfamiliarity with the basic facts of chemistry causes them to make patently ridiculous alarmist statements and then double down on them when corrected. And more times than I can count, if said statements are in a public venue like a comment thread, someone will pipe up by repeating a particular increasingly stale joke. Say it’s a discussion of contaminants in tap water allegedly stemming from hydraulic fracturing for natural gas extraction. Said wit will respond with something like: “You know what else might be coming out of your tap? DIHYDROGEN MONOXIDE!”

Two hydrogens, one oxygen … what's coming out of your tap here is water. Hilarious! Or perhaps not.

Clarke argues that those in the chemical know whip out the dihydrogen monoxide joke to have a laugh at the expense of someone who doesn't have enough chemical knowledge to understand whether conditions they find alarming really ought to alarm them. However, how it usually goes down is that other chemically literate people in earshot laugh while the target of the joke ends up with no better chemical understanding of things.

Really, all the target of the joke learns is that the teller of the joke has knowledge and is willing to use it to make someone else look dumb.

Clarke explains:

Ignorance of science is an evil that for the most part is foisted upon the ignorant. The dihydrogen monoxide joke depends for its humor on ridiculing the victims of that state of affairs, while offering no solution (pun sort of intended) to the ignorance it mocks. It’s like the phrase “chemophobia.” It’s a clan marker for the Smarter Than You tribe. The dihydrogen monoxide joke punches down, in other words. It mocks people for not having had access to a good education. And the fact that many of its practitioners use it in order to belittle utterly valid environmental concerns, in the style of (for instance) Penn Jillette, makes it all the worse — even if those concerns aren’t always expressed in phraseology a chemist would find beyond reproach, or with math that necessarily works out on close examination.

There's a weird way in which punching down with the dihydrogen monoxide joke is the evil twin of the "deficit model" in science communication.

The deficit model assumes that the focus in science communication to audiences of non-scientists should be squarely on filling in gaps in their scientific knowledge, teaching people facts and theories that they didn't already know, as if that is the main thing they must want from science. (It's worth noting that the deficit model seems to assume a pretty unidirectional flow of information, from the science communicator to the non-scientist.)

The dihydrogen monoxide joke, used the way Clarke describes, identifies a gap in understanding and then, instead of trying to fill it, points and laughs. If the deficit model naïvely assumes that filling gaps in knowledge will make the public cool with science, this kind of deployment of the dihydrogen monoxide joke seems unlikely to provoke any warm feelings towards science or scientists from the person with a gappy understanding.

What's more, this kind of joking misses an opportunity to engage with what they're really worried about and why. Are they scared of chemicals per se? Of being at the mercy of others who have information about which chemicals can hurt us (and in which amounts) and/or who have more knowledge about or control of where those chemicals are in our environment? Do they not trust scientists at all, or are they primarily concerned about whether they can trust scientists in the employ of multinational corporations?

Do their concerns have more to do with the information and understanding our policymakers have with regard to chemicals in our world -- particularly about whether these policymakers have enough to keep us relatively safe, or about whether they have the political will to do so?

Actually having a conversation and listening to what people are worried about could help. It might turn out that people with the relevant scientific knowledge to laugh at the dihydrogen monoxide joke and those without share a lot of the same concerns.

Andrew Bissette notes that there are instances where the dihydrogen monoxide joke isn't punching down but punching up, where educated people who should know better use large platforms to take advantage of the ignorant. So perhaps it's not the case that we need a permanent moratorium on the joke so much as more careful thought about what we hope to accomplish with it.

Let's return to Chris Clarke's claim that the term "chemophobia" is "a clan marker for the Smarter Than You tribe."

Lots of chemists in the blogosphere regularly blog and tweet about chemophobia. If they took to relentlessly tagging as "chemophobe!" people who are lacking access to the body of knowledge and patterns of reasoning that define chemistry, I'd agree that it was the same kind of punching down as the use of the dihydrogen monoxide joke Clarke describes. To the extent that chemists are actually doing this to assert membership in the Smarter Than You tribe, I think it's counterproductive and mean to boot, and we should cut it out.

But, knowing the folks I do who blog and tweet about chemophobia, I'm pretty sure their goal is not to maintain clear boundaries between The Smart and The Dumb. When they fire off a #chemophobia tweet, it's almost like they're sending up the Batsignal, rallying their chemical community to fight some kind of crime.

So what is it these chemists -- the people who have access to the body of knowledge and patterns of reasoning that define chemistry -- find problematic about the "chemophobia" of others? What do they hope to accomplish by pointing it out?

Part of where they're coming from is probably grounded in good old fashioned deficit-model reasoning, but with more emphasis on helping others learn a bit of chemistry because it's cool. There's usually a conviction that the basics of the chemistry that expose the coolness are not beyond the grasp of adults of normal intelligence -- if only we explain in accessibly enough. Ash Jogalekar suggests more concerted efforts in this direction, proposing a lobby for chemistry (not the chemical industry) that takes account of how people feel about chemistry and what they want to know. However it's done, the impulse to expose the cool workings of a bit of the world to those who want to understand them should be offered as a kindness. Otherwise, we're doing it wrong.

Another part of what moves the chemists I know who are concerned with chemophobia is that they don't want people who are not at home with chemistry to get played. They don't want them to be vulnerable to quack doctors, nor to merchants of doubt trying to undermine sound science to advance a particular economic or political end, nor to people trying to make a buck with misleading claims, nor to legitimately confused people who think they know much more than they really do.

People with chemical know-how could help address this kind of vulnerability, being partners to help sort out the reliable information from the bogus, the overblown risks from risks that ought to be taken seriously or investigated further.

But short of teaching the folks without access to the body of knowledge and patterns of reasoning that define chemistry everything they know to be their own experts (which is the deficit model again), providing this kind of help requires cultivating trust. It requires taking the people to whom your offering the help seriously, recognizing that gaps in their chemical understanding don't make them unintelligent or of less value as human beings.

And laughing at the expense of the people who could use your help -- using your superior chemical knowledge to punch down -- seems unlikely to foster that trust.