Widely considered to be an influential philosopher in the animal rights movement after his book Animal Liberation was published in 1975, Peter Singer is the Ira W. DeCamp professor of bioethics at the University Center for Human Values at Princeton University. He has written, co-authored, edited or co-edited more than 50 books, including Why Vegan? and The Way We Eat: Why Our Food Choices Matter. 

Why is food an ethical issue?

There are several reasons for making food an ethical issue and changing what we’re eating. One is that producing food has an enormous impact on the environment. About 25 percent of all human greenhouse gas emissions come from food production. It’s also an enormous source of animal suffering. Over 70 billion animals are raised and killed each year worldwide, and the majority of them are in intensive factory farms. Their lives are miserable for most of the time. And finally, factory farms are breeding grounds for new viruses. We’ve had swine flu and avian flu coming out of factory farms. It’s quite possible that the next pandemic will originate there. 

Is it unethical to contribute to climate change? 

It’s impossible to live without contributing to climate change, but it’s unethical to unnecessarily contribute to climate change when you can live in a way that has a lower greenhouse gas footprint. You could say luxury emissions are unethical while survival emissions are necessary, and so one can’t regard them as unethical. 

What are the most important food choices that we can make from an ethical standpoint?

Avoiding animal products is probably the first and most important ethical choice one can make. That’s going to dramatically lower your carbon footprint. You will no longer be complicit in the suffering of those tens of billions of factory-farmed animals, and you won’t be contributing to the increasing risks of viruses being bred in factory farms. 

Is eating animals all right if they are raised humanely and don’t suffer when they are harvested?

If animals aren’t suffering and have good lives, that’s a big improvement from the point of view of the animals, but it doesn’t overcome other problems. Grass-fed cattle may have good lives, but they continue to emit large quantities of greenhouse gases, methane in particular. Is painless killing of an animal that has led a good life acceptable? There’s an argument that it is, that at least they had a life, otherwise they wouldn’t have existed at all, so it’s not wrong. People are going to accept or reject that. There isn’t a clear-cut answer. It’s a complicated issue, so that’s why I tend to focus on the fact that large-scale commercial rearing of animals inevitably causes suffering for them and exploits them. Yes, they can come from very small farms where animals are looked after and cared for, but it won’t likely happen on a large commercial scale. 

Is there a hierarchy of animals that might be ethically okay to eat? 

I’m not really concerned about all animals in the zoological sense. I’m concerned about sentient beings or animals capable of suffering or enjoying their lives, and I don’t see that as necessarily coinciding with the boundary between plants and animals. So, oysters or clams or mussels, the simple bivalves, are clearly animals in zoological terms, but there’s good reason to believe that they don’t have a sufficiently complicated nervous system to feel pain, and if that’s the case, then I don’t think there’s an objection to eating those animals as long as they are farmed or raised in a sustainable way that doesn’t harm the environment. 

Are you hopeful that more people will adopt ethical eating habits in the future? 

The huge increase in the availability of vegan products pretty much around the world is a great sign of hope, because what we need to do is to reach a critical mass where these products are not only available, but are also comparative in cost with animal products. Once that day comes, I think we’ll get far more people switching, where they really don’t have to change their diet that much, they don’t have to spend that much more and they can avoid all these negative ethical aspects and be healthier themselves. 

Sandra Yeyati, J.D., is a professional writer. Reach her at [email protected].