Global ChangeIntersection of Nature and Culture

Ethical eating: Should we expand the circle to include plants?

Tuesday, December 22nd, 2009

In a NY Times column yesterday, Sorry, Vegans: Brussels Sprouts Like to Live, Too, Natalie Angier pushes the boundaries of what we consider to be ethical eating.

She works through a series of biochemical and physiological examples of how plants are amazing—almost animal-like.  With one of my undergraduate majors in botany, I agree:  Plants are amazing and animal-like.

Attacked by an herbivove?  Plants can emit volatile chemicals to warn other individuals of the same species (analogous to a warning call). They can turn on chemical defenses that make themselves less palatable (an immune response).  And in an amazing display of evolution, some plants can even send signals to the predators of the herbivore to come get a free meal (analogous to getting your big brother to beat up the bully picking on you). For example, some corn varieties when being eaten by insect larva emit a chemical signal to attract wasps that lay eggs in the herbivorous pests, turning the pest into a tasty meal.

But being animal-like doesn’t mean we ought to give plants the same ethical considerations as animals.  Sure, plants are amazing, but that’s not a particularly effective ethical argument for diet choices for a couple of reasons:

• Plants, without well-developed brains and nervous systems, are not sentient beings with a capacity to suffer or a will to live (sorry Brussels sprouts).  They are watery bags of enzymes and genes with exquisite biochemical and physiological responses.  They are essentially green cellulose robots that are evolutionarily and genetically programmed to respond in complex ways to complex and multifaceted environmental stimuli.  Eating plants, as many ethicists would argue, is therefore less morally challenging than eating a sentient mammal that can feel pain and possibly possesses a will to live.  Just like smashing a mosquito is less morally challenging than smashing your pet dog.
• We have to eat something.  And until the day comes when we can mass produce food from tissue culture (don’t laugh, people are trying to culture meat in test tubes), we will have to eat living organisms.  Three arguments strongly favor plants over animals in terms of food ethics and sustainability:  (1) Plants have less capacity to suffer and feel pain (although some primitive animals like mussels and oysters may fall into this category), (2) we can feed a lot more people on a diet of plants than a diet of animals, as noted in an earlier post, and (3) growing plants for food releases fewer greenhouse gases than raising livestock.

It’s hard to tell whether Angier is being serious or satirical (and whether the rest of the blogosphere and I are being punked by developing an elaborate rebuttal).  The following passage suggests the former:

But before we cede the entire moral penthouse to “committed vegetarians” and “strong ethical vegans,” we might consider that plants no more aspire to being stir-fried in a wok than a hog aspires to being peppercorn-studded in my Christmas clay pot. This is not meant as a trite argument or a chuckled aside. Plants are lively and seek to keep it that way.

Nevertheless, her argument is flawed because it asks us to equate the moral consideration of sentient animals (like pigs) and plants.  I don’t know of a single ethicist who would make this argument given what we know about intelligence and sentience.

Furthermore, by equating plants and animals ethically, she implicitly uses this to justify eating meat because plants are objects of moral consideration too.  As the title of her article insinuates, if we are no longer able to eat Brussels sprouts, we must not be able to eat anything because of ethical equivalency.  We are led to conclude that this is absurd, so, therefore, we should just chill out and eat anything we want.

What Angier’s argument lacks in ethical rigor, it makes up in one important way:  It asks people to be thoughtful about what it means to eat other organisms.  Humanity should recognize and marvel at these amazing plant evolutionary adaptations—even be thankful for them—and do what we can to preserve them over the long haul.

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Photo credit:  http://www.flickr.com/photos/sea-turtle/ / CC BY-NC-ND 2.0