-- A. Whitney Brown

A friend turned me on to a piece in yesterday's New York Times (http://www.nytimes.com/2009/12/22/science/22angi.html) that purported to advance a case against the perceived moral superiority of people who consume plants instead of animals. Natalie Angier's "Sorry Vegans: Brussels Sprouts Like to Live, Too" argued that meat-eaters should not "cede the entire moral penthouse" to herbivorous humans because"[p]lants [like animals] are lively and seek to keep it that way".



(Note: Ms. Angier specifically insisted that she was serious, that this "is not meant as a trite argument or chuckled aside". So I'm taking her word for it and responding as if the article wasn't intended to be mere column filler. I'd ask that my readers bear this in mind before they write in and claim that vegetarianism has made me both iron and irony deficient.)



Ms. Angier proceeded to describe some of the surprising ways that plants help to ensure their own survival. As someone who loves learning about the natural world, I am endlessly fascinated with the clever self-preservative tricks that Earth's organisms have devised. In plants, these range from resource foraging (e. ., growth oriented toward brightly-lit and nutritive soils) to chemical warfare (e.g., releasing irritants to ward off nibbling predatory insects). Plants are certainly far more complex and worthy of examination than many people think -- and than most biology curricula demand, my own undergraduate studies included. It's always nice to see plants get their brief moments in the sun.



But from these descriptions of how plants deal with the sometimes nasty vicissitudes of their lives, Ms. Angier extrapolates a fairly ridiculous conclusion: that vegetarians cannot (on the basis of their diets) claim to be living any more ethically than their carnivorous neighbours. Why? Because plants, like animals, "fight to survive".



Well, of course they do. Survival and reproduction are the two core biological imperatives, the literal sine quibus non (‘without which, nothing') of all species. Life, to the extent that it can truly be said to be purposeful, has an overarching ‘goal' of ensuring more life. Evolutionary mechanisms thus ensure that survival and are emergent properties of species. In that sense all living things, including plants, should ‘like' or ‘want' to live and reproduce. (Using mental metaphors to describe non-humans is fraught with intellectual peril, which is why I put these and similar terms in scare quotes.)



But by that definitional logic, so too do Ebola viruses, cancers, and liver flukes ‘like' to live and reproduce. Indeed, they're all quite frighteningly good at it -- weakening and ultimately killing their hosts as they successfully multiply. So, Ms. Angier, shall we be truly ethical, let life take an absolutely natural course, and shut down our hospitals? This is a clearly silly conclusion.



To live, we humans must consume some form of nutritive biomass; rocks and sunlight just won't cut it. We can agree that all plants and animals have the ‘goal' of survival. We can agree that by eating them, humans generally frustrate that goal -- fictional creatures like Schmoos (http://en.wikipedia.org/wiki/Shmoo) and Ameglian Major Cows (http://www.youtube.com/watch?v=C1nxaQhsaaw) notwithstanding. And we can agree that we do not yet have the needed technology to circumvent this problem. (The food replicators of Star Trek could do the trick nicely; alas, they remain the stuff of fiction.)



So shall we vegetarians fall upon our forks? Are we doomed to learn the mystical secrets of breatharians (http://en.wikipedia.org/wiki/Inedia) or else waste away, starving but self-satisfied?



Plants, it is true, are laden with features -- like thorns, trichomes, and toxins -- that reduce the chances they will be targeted by herbivores or parasites. Such features likely evolved primarily for protective value rather than, say, for sturdiness or as accidental metabolic byproducts. Recent evidence even suggests that some plant species can recognize genetic kin in their surroundings and may even behave ‘altruistically'. For example, plants might show slower growth in the presence of close relatives, implying a possible sharing of available soil and water resources (http://www.wired.com/wiredscience/2009/11/plant-family-values/).



So can plants detect tissue damage and respond to environmental threats? Almost certainly. Can they feel and pain in a way that we can comprehend? Almost certainly not. The best evidence we have at present concerning plant anatomy and physiology would imply that they could not -- even in principle -- have psychological experiences comparable to animal species. Plants have no discernable brains or other nervous tissues. Stimulus response cannot be equated to "feelings" or "consciousness".



But if plants can feel pain, it actually makes the argument against meat-eating even stronger. Why? Simple: if you trace down the food chain for almost any animal species, the base of the food pyramid is going to be composed of plant material. Up to 90% of biomass energy gets lost each time we move up a link in the chain. If grass feels pain, and you eat two pounds of beef (which required, let's say, 15 agonized pounds of digested grass to produce), then you've indirectly caused needless extra suffering.



Ms. Angier also ignores the fact that some plants actually count on being consumed -- in whole or in part -- for their unique life cycle mechanisms to occur. For example, many plants grow berries and seeds with the ‘intent' that these be eaten and later deposited at some new growing location. (And in a fresh pile of fertilizer, no less!) I am hard-pressed to think of any non-parasitic animal that does the same.

In summation, to Ms. Angier and her ideological supporters, if you think that you'll ever see the same kind of terror in the eyes of an uprooted Idaho potato as you will in those of a slaughtered Jersey cow, I would respectfully suggest that you're kidding yourself. If you want to eat meat, do it. But don't try to argue for moral equivalence with absurd tu quoque arguments.

And to my colleagues and constant readers here at PT... Thank you for your engaging comments over the past months. Whether or not you've agreed with what I've written, I hope that my little corner of the blogosphere has merited an occasional glance and prompted some critical thought. I have sincerely appreciated the positive feedback and tried to learn from the constructive criticism. I look forward to conveying -edge cognitive comestibles to chew on come 2010.

Have a safe and happy holiday season!!

Extra Credit Section



If I listen closely, I can almost hear the wheels of spinning out there. Many readers who were previously salivating in anticipation of this weekend's impending ham or turkey feast are now simply frothing. So, let me preemptively address some of the most probable responses:



"Eating meat is pleasurable -- more than its alternatives, certainly. Therefore, I choose to do it."

This is a childish argument from hedonic consequence. My wife -- a happy meat eater -- thinks that childish is too strong a word, but I disagree. Replace "Eating meat" with "Unprotected " (or, perhaps, "Punching preachy vegetarians in the face") and you can quickly see why.

Most schools of hedonic require that you consider the costs of your actions, not just the benefits. Indeed, Epicurus, a major philosophical father of this line of ethical thought, clearly insisted in his Letter to Menoeceus that the good life is obtained through careful reflection about behavioural choices, not "the enjoyment of the fish and other delicacies of a luxurious table".



(By the way, in case you're wondering: I actually quite enjoy the taste of meat. Before I became a vegetarian, I was one of those people who relished eating almost any species that crossed my path. I ate all manner of fish, fowl, mammals, crustaceans, and insects. I regularly miss the taste of bacon double cheeseburgers, eel sashimi, Cajun-blackened flounder, pepperoni pizza, my father's Chicken Kiev, venison sausage, and countless other delicacies. Once the technology is safe, common and affordable, I look forward to guiltlessly enjoying in vitro steak. Until then, my tastebuds must take a back seat to my cerebrum.)

"Meat tastes good to us -- better than meat alternatives, certainly. We have an omnivorous dentition pattern that includes teeth specialized for meat eating. Meat contains essential nutrients (e.g., iron and some amino acids) that are inconvenient to obtain from vegetarian diets. This all proves that we evolved to eat meat. Therefore, a vegetarian is unnatural."

More sophisticated; still faulty. Evidence uncovered by anatomists (e.g., skeletal and gastrointestinal structures) and archeologists (e.g., primitive hunting and fishing tools) clearly suggest that the human diet has traditionally included meats and anything else that we've found to be edible. Biologically, we appear to be built for opportunistic omnivory.

But so what? As even our most ardent evolutionary psychologists here at PT would concede, what characterized or benefited our early human ancestors cannot be used as solely sufficient grounds to justify current practices. This is what is often called the appeal to nature.

According to some anthropological evidence, cannibalism was also prevalent among early humans. One can easily imagine its advantages during times of famine (as a source of food), (as a way to ritualistically honour the dead), and war (as a way to scare off potential attackers). Certainly, the same teeth we use to tuck into a cow's leg would be just as effective on a human's. (Maybe even more effective -- our skin isn't nearly as thick as a cow's.) Why not revert to this ‘natural' practice as well?



Getting your iron and amino acids from drugstore supplements, like I mostly do, is unquestionably an unnatural act. But so too is writing e-mail, working in an air-conditioned office, flying through the air at supersonic speeds... all common practices in our modern world. Cultural evolution outpaces biological evolution, and for very good reasons. Changing dietary practice to fit current scientific and moral theory is a predictable and desirable aspect of such cultural evolutions.

"Animals do not have a sophisticated sense of their own mortality (or that of their conspecifics). Therefore they cannot be said to truly suffer, because they cannot comprehend what it is that they are losing."



The premise here may be quite faulty. The fact is that we do not really know what animals know about their own mortality. Animals certainly behave as if they desire to live -- eating and drinking regularly, avoiding painful stimuli, hiding and escaping from known predators, etc.

Are these behaviours "mere instincts"? If so, some argue, we can comfortably treat animals like useful living machines -- as products to be consumed. Unfortunately, we humans have not figured out a clever and conclusive way to find out for sure. For one thing, we tend to use human standards (e.g., ritualized burial) to judge the behaviour of other animals. For another, the history of comparative psychology is fraught with retractions:



"Only humans can fashion and strategically use tools... Oops, guess not. Chimps and ravens, huh?

But, of course, only humans act altruistically... Oops, wrong again. Ground squirrels and termites, you say?

Surely only humans are capable of understanding symbolic language and number lines... What? Chimps? AGAIN?!

Well, it's quite obvious that only humans are capable of self-recognition. What? Dolphins?!?

That's it, I quit."



The line between Homo sapiens and the rest of the animal world blurs and shifts as our tools of inquiry improve. To me, it is not a grand leap to suggest that animals do things in order to preserve life and avoid death, and not a much grander leap beyond that to suggest that they avoid death because they are aware of its finality.



But I may be wrong. Let's say I am, and let's assume the original premise is true -- that animals are truly unaware of their mortality. The same could be said for some humans, such as newborns and the comatose; this is commonly referred in moral as the argument from marginal cases.

So, if you favor this argument, practice what you preach. Go take a big bite out of Baby New Year and get back to me.

"On average, you have to eat many more plants (e.g., grapes) than animals (e.g., cows) to obtain the same amount of food value. If all life is objectively worth the same amount, then meat-eating involves less overall killing and therefore is more ethical."



I personally make no claim that all life is worth the same. Indeed, I find it difficult to see how such a concept of worth could be objectively measured in the first place. And one could pretty handily argue the math involved here. (See my previous "food chain" example.)

But this is certainly an interesting position and not unheard of in world philosophy. For example, Jainism, a dharmic religion, is predicated on the idea that all living things are ensouled. The Jain philosophy advocates non-violence toward all living organisms, and involves dietary practices that extend well beyond common vegetarianism. Strict Jains refuse to eat any food obtained through violent means. So, onions are out -- harvesting root foods causes unnecessary deaths of healthy plants.

Yet even their rigorous behavioural code has some glaring loopholes. For example, Jains commonly boil water and then cool it to a comfortable drinking temperature, thus doing "violence" to millions of ensouled microorganisms that would have otherwise lived a contented life within their guts. (The guts of the Jains, of course, would suddenly become far less contented.)

It is common knowledge that microorganisms react to environmental stressors with complex electrochemical signals and escape movements. As you read this millions of bacteria are living a content existence upon your skin, and will remain relatively undisturbed in their colonies until you next scour your body with hot water and soap.

I wonder if Natalie Angier will shed a tear for those little ones while washing up before sitting down to her crispy Christmas duck. After all, if she's scrubbing correctly, she'll be committing microbial genocide on an absolutely staggering scale!