Veterinarian and epidemiologist Waltner-Toews’s The Origin of Feces: What Excrement Tells Us About Evolution, Ecology, and a Sustainable Society is a comprehensive look at the social and ecological history of excrement, and global problems we face today.

Why did you decide to write a book about feces?

My professional life is spent working in epidemiology and diseases; the stimulus was probably because of the increasing rates of diseases related to excrement, and I wondered about that. I’ve had a long interest in ecology and framing relationships. I started thinking: how did we take a natural renewal source and make it into something that is a problem? That raised other questions: we haven’t raised the mass on the globe, but if farms are piling up shit, what is disappearing?

Almost the first problem you tackle is what kind of language you are going to use to talk about excrement. Why was that a problem?

There are two categories of language we use when talking about waste. The first are the technical words in my working life: biosolid management or nutrient management—how you handle manure. It’s useful from a technical point of view but if you go to a public forum and talking about biosolids most people would go blank. On the other side you have the locker room language, the shit words and the shit-related words, the language related to snickering. We don’t have a good public language to talk about something that everybody does daily—more or less—and it’s become a huge environmental and public health problem. We need to talk about it, but we don’t have a good language. The World Toilet Association uses the word “excrement”. It’s probably the best middle-of-the-road word without offending anybody. I came to (in the end) using multiple words: “number two”, “frass”, “fecal matter”, “shit”.

You’ve described waste as a “wicked” problem due to the concerns that the hard sciences—engineering, biology, chemistry—cannot solve the problem alone. What else is needed?

The hard sciences are good at fine distinctions. In fact, tracing bacteria through shit or looking for DNA in wildlife scat: they are very good at that. But when you’re working with individual communities, you are trying to integrate lots of different perspectives: values, historical determinations, et cetera. To me, this is the “really difficult” science. You have a lot of trade-offs in a social landscape. If you use water for flushing and this causes water shortages, you’re fixing one problem (waste removal) and making another one (water shortages) considerably worse. These kinds of trade-offs is where the “really difficult” science comes in. It’s not a matter of identifying the pieces, but discussing the dynamics of what’s on the planet and what kind of planet we want to live on. There’s a value statement there.

How have societies dealt with shit in the past?

Societies have always been aware of the problem of excrement. Hercules’s fifth labor was to divert rivers to remove excrement—basically the flush toilet. So there isn’t a linear progression—we haven’t gone from being primitive and dirty to modern and clean. The Romans had flush toilets, and then the flush toilets disappeared. 18th century Japan shipped their waste from the city to the countryside; there was recognition that shit was an important source of renewal. In the industrial revolution, when people began discovering fossil fuels, that awareness tends to disappear, and what moved to the surface was the other part of the equation: that there are risks associated with animal and human feces. There’s always been the conflict between waste as associated with bacteria and disease and waste as a nutrient.

What would you hope readers take away from reading The Origin of Feces?

I would like to see a reintegration when people talk about agriculture and food systems. Not “what do you do with manure because it’s a problem,” but “how can we improve the way we produce and distribute food that accommodates the fact that animals and people are producing shit.” It seems we’ve lost our peripheral vision of the problem. We’re very good at focusing in and finding solutions to a specific problem, but not very good at seeing the other problems we’ve made.

What I would like to do is get people to consider more integrative solutions. It’s not a problem of parasites and animals; it’s how it fits into the landscape. There isn’t a silver bullet to accomplish everything, but if we back off trying to control everything and look at relationships in ecosystems, in the long run we’re going to be better off.