I. Plants: They React; They Don’t Respond

Every now and then, the internet lights up with the most recent claim that new evidence indicates that plants are sentient; that is, that they are conscious and have some sort of mind and are relevantly similar to animals.

The evidence on which these claims are based establishes at most that plants are alive and conduct various activities, some of which are very complex. That is, the evidence shows that plants react; it does not show that plants respond. For example, in his 2012 book, What a Plant Knows: A Field Guide to the Senses, Tel Aviv University scientist Daniel Chamovitz wrote that plants could see, smell, and hear. This gave rise to a wealth of claims in the popular media that plants were sentient. But when Scientific American interviewed Chamovitz and asked him point blank, “Would you say, then, that plants ‘think’?” Chamovitz replied, “No, I wouldn’t.” He added, “Just as a plant can’t suffer subjective pain in the absence of a brain, I also don’t think that it thinks.”

Philosopher Michael Marder, author of Plant-Thinking: A Philosophy of Vegetal Life (2103) made headlines when he was credited with claiming that plants are sentient. In a debate that I had with Marder, I asked him whether he thought plants were sentient. He responded that he thought that they were capable of “nonconscious intentionality.” What in the world does that mean? How can one intend to do something in a nonconscious way? Isn’t consciousness necessary for intention? Do plants engage in activities that achieve certain states of affairs? Yes. But it begs the question to talk about “intentionality” in this context. At this very moment, there are all sorts of complex biological processes going on in our bodies. We hope that these processes are conducted toward certain ends, such as cellular repair, and not toward other ends, such as tumor formation. But can we talk about the “intentionality” of cancer cells? Only if we assume that cellular reactions have a cognitive component. We could say that the electrically charged particles that travel down the wire are nonconsciously intending to make the bell sound. But we wouldn’t say that because it would be silly to do so.

I do not believe that there is any evidence whatsoever that plants are sentient in the sense of being subjectively aware and able to experience pain and suffering. I do not believe that that there is any evidence that plants have minds that prefer, desire, or want any state of affairs. But I am not presently interested in debating whether plants are sentient.

Rather, I want to argue that claims about plant sentience have nothing to do with any sincere interest in plant sentience. The real interest in plant sentience is in challenging the claim that we cannot morally justify continuing to exploit the billions of cows, chickens, pigs, sheep, fishes, etc. That is, the plant sentience argument is, in a nutshell: we can’t avoid exploiting sentient beings because plants are (supposedly) sentient so it’s fine for us to keep exploiting nonhuman animals. In other words, your salad involved killing sentient beings so go ahead and enjoy that steak.

II. Look at What Recognizing Sentience Has Done for Nonhuman Animals: Nothing

The evidence for plant sentience is non-existent in my view but is, at best, highly speculative. The evidence for animal sentience is certain. Indeed, our recognition of animal sentience is so well-established that we have laws — criminal laws — that reflect the moral principle that we should not impose “unnecessary suffering” on animals and that we should treat them “humanely.” None of these laws, and the moral ideas that animate them, would make any sense whatsoever if animals were not sentient. You cannot impose “unnecessary suffering” on a being who cannot suffer.

According to the Cambridge Declaration on Consciousness, all mammals and birds are undoubtedly sentient as are cephalopod mollusks such as octopuses. There has long been scientifically sound evidence of the sentience of fish and fish sentience is now widely accepted. Yes, there are philosophers who find consciousness to present all sorts of puzzles, and there are still a very few who deny that animals are conscious, but there are philosophers who tells us that our own consciousness is just an illusion. But this is all academic in the worst sense of the word. There is no real controversy about the existence of animal sentience. Yes, we may not be sure about clams and mussels but there is no doubt about the overwhelming majority of the billions of animals we exploit.

How has our certainty about animal sentience changed our behavior? That’s easy: it hasn’t.

When we recognized the moral importance of animal suffering in the 18th century, we bifurcated the interest of animals in not suffering from their interest in remaining alive. A primary architect of this thinking was lawyer and philosopher Jeremy Bentham. He argued that animals did not care that we used and killed them but only cared about how we treated and slaughtered them. They did not want to suffer but they were indifferent to whether they lived.

In arguing that animals mattered morally because they suffered, and that it was not necessary for them to have other cognitive characteristics, Bentham noted that the French had already rejected the idea that the skin color of humans should allow them to be enslaved and “abandoned without redress to the caprice of a tormentor,” and added:

[i]t may come one day to be recognised, that the number of the legs, the villosity of the skin, or the termination of the os sacrum, are reasons equally insufficient for abandoning a sensitive being to the same fate? What else is it that should trace the insuperable line? Is it the faculty of reason, or, perhaps, the faculty of discourse? But a full-grown horse or dog is beyond comparison a more rational, as well as a more conversable animal, than an infant of a day, or a week, or even a month old. But suppose the case were otherwise, what would it avail? the question is not, Can they reason? nor, Can they talk? but, Can they suffer?

But that did not mean that we could not use and kill them. According to Bentham, animals do not care that we use and kill them; they care only about how we treat them and kill them. If we kill and eat them,

we are the better for it, and they are never the worse. They have none of those long-protracted anticipations of future misery which we have.

He also maintained that we actually do animals a favor by killing them, as long as we do so in a relatively painless manner:

The death they suffer in our hands commonly is, and always may be, a speedier, and by that means a less painful one, than that which would await them in the inevitable course of nature.

That is, we decided that, although animals, because they are sentient, have an interest in not suffering, they do not have an interest in continuing to live because they are not self-aware. So we can use and kill them for our purposes as long as we treat them “humanely?” and don’t impose “unnecessary suffering” on them. This gave us a green light to continue to exploit animals subject to the limitation that we accord weight to the interest of animals in not suffering.

The problem is that this supposed limitation was no real limitation. Animals are property with an economic value and, as I discussed in Animals. Property, and the Law, Animals as Persons, The Animal Rights Debate, and other work, because it costs money to protect animal interests, the level of protection we accord to their interests is pretty low. Indeed, the treatment we accord to the animals who are the most “humanely” treated (the animals who are part of the niche market that goes beyond the legal requirements and supplies supposedly more “humane” animal products to those who are willing to pay more) are treated in ways that would be characterized as “torture” were humans involved. And the killing of animals — however supposedly “humane” it is — requires that we buy into the nonsensical position that a sentient being does not have an interest in continuing to live because that being is not self-aware in the way that most humans are.

As I discuss in Why Veganism Matters: The Moral Value of Animals, the accepted position amongst philosophers who believe that animals matter morally is that, although animal sentience is sufficient for the moral relevance of animal suffering, it is not sufficient for recognizing that animals have a morally significant interest in continuing to live. More is required. We need to be able to show that animals are not only sentient but have minds that are similar in relevant ways to the minds of typically-functioning humans. And nonhuman animals can never win what I call the “similar-minds” game. However similar their minds are to ours, they are not similar enough to require that we stop using and killing them — however supposedly “humanely” we do so.

We all claim to embrace that it is wrong to impose “unnecessary suffering” on animals, but we don’t need to consume animal products for optimal health. So, by definition, we impose unnecessary suffering on the approximately 80 billion land animals and the unknown number of sea animals (one trillion being the lowest estimate) we kill every year for food. To put this in perspective, we kill more animals every year for food alone than the number of human beings who have ever lived on the planet. Not only is all of this suffering and death unnecessary; it is an ecological catastrophe. Animal agriculture accounts for more greenhouse gases being spewed into the atmosphere than all of the fossil fuels we burn for transportation.

In sum, our recognition of certain animal sentience has had no significant effect on our behavior. But it does make us, or at least many of us, most uncomfortable. As just about any vegan can tell you — and this vegan will certainly tell you — one’s mere presence at a dinner party at which one is not partaking of the animal products served — even in the complete absence of any proselytizing —virtually guarantees a hostile reaction from other guests who will almost certainly remark about and lament the death of the vegetables on the vegan’s plate. Do any of those guests really think that the vegetables suffered? Of course not. But plant sentience makes those guests feel good about chomping on all of the animal products served.

III. Corn Carnage

All of this chatter about plant sentience serves one and only one purpose: it makes those who are uncomfortable about our exploitation of animals feel more comfortable about continuing to exploit animals. I have known many nonvegans who have called a local humane society to report the abuse by a neighbor of an animal. I have never known anyone — including my philosopher friends who purport to take seriously the moral importance of plant sentience — to call the humane society upon seeing a neighbor mow their lawn.

I was motivated to write this particular essay by a Facebook post on Philosophy Matters linking to an article that claimed plants feel and may even be able to see. The post caption was “Bad News For Vegans: Plants Feel Pain and Might Even See.” In other words, the vegetables you eat are no different from a cow and that’s bad news if you aren’t eating the cow because you think that the cow is relevantly different from vegetables.

There are literally thousands of articles and posts about how vegans need to get over it and recognize that they are morally no different from those who eat animal products because vegans are killing sentient plants. One essay, “No Face, but Plants Like Life Too,” stands out in my mind as perfectly representing the “vegans and nonvegans are both killers” approach, was written in 2011 by Carol Kaesuk Yoon:

Yoon writes that although she gave up eating meat:

My entry into what seemed the moral high ground, though, was surprisingly unpleasant. I felt embattled not only by a bizarrely intense lust for chicken but nightmares in which I would be eating a gorgeous, rare steak — I could distinctly taste the savory drippings — from which I awoke in a panic, until I realized that I had been carnivorous only in my imagination.

Temptations and trials were everywhere. The most surprising turned out to be the realization that I couldn’t actually explain to myself or anyone else why killing an animal was any worse than killing the many plants I was now eating.

Yoon found that:

formulating a truly rational rationale for not eating animals, at least while consuming all sorts of other organisms, was difficult, maybe even impossible.

She states:

Plants don’t seem to mind being killed, at least as far as we can see. But that may be exactly the difficulty.

Unlike a lowing, running cow, a plant’s reactions to attack are much harder for us to detect. But just like a chicken running around without its head, the body of a corn plant torn from the soil or sliced into pieces struggles to save itself, just as vigorously and just as uselessly, if much less obviously to the human ear and eye.

This essay did not appear on some alternative, new-age website talking about spirituality and plants. It was in the Science section of the New York Times. Remarkable.

IV. But What If Plants Are Sentient? Answer: Eat Plants

But let’s play along for a minute. Let’s assume that plants are sentient; that they, like sentient humans and nonhumans, are subjectively aware and have minds that prefer, desire, or want not to suffer and to remain alive. What should we do if that were the case? Well, first, we would need to decide whether we were going to choose to starve to death. Second, if we decided that we were going to say alive, what should we eat?

The answer is simple: even if plants are sentient, and are thereby subjectively aware, we should continue to eat them.

The simple and indisputable fact is that it takes many times more plants to produce the same quantity of animal foods. Take a look at this chart:

As the chart indicates, when you eat that kilogram of beef, you are consuming 25 kilograms of sentient plants who, according to Carol Kaesuk Yoon, wanted to live. So if you really thought plants were sentient, and decided that you were not willing to starve to death but wanted to act as morally as possible, you’d consume the plants directly. You certainly wouldn’t suggest that plant sentience is a reason to not be vegan.

A related attack on veganism is that, because animals are incidentally and unintentionally killed in the process of planting, growing, and harvesting crops, those who eat plants are just as morally culpable as those who eat animals because the former are also responsible for animal deaths. Putting aside that this argument ignores that human activities (such as building roads and driving on those roads) result in humans being incidentally and unintentionally killed but we still have no problem distinguishing those deaths from murder, it ignores the plain and indisputable fact that eating animal foods means that we have more acres under cultivation than we would have if we were all vegans. As the chart below shows, if we were all vegan, we could reduce the acreage under cultivation for plants by 75{967bf23b37ec6a673a83041540b3f904a815b4119ddf673afb961c1e7592ebdd} — from 4.13 billion hectares (one hectare is 2.47 acres) to one billion hectares. Think about that. If plants are sentient, eating only plants saves one hell of a lot of plants and it reduces dramatically the number of animals who are incidentally and unintentionally killed.

I know that many vegans find the “plant sentience” argument to be maddening. As someone who has heard this argument probably thousands of times over the years, I understand the frustration. But I always see an opportunity for further discussion. That is, it’s such an appallingly poor argument, the fact that anyone makes it means that they are troubled by the exploitation of animals but have little to say. They can often be persuaded to think seriously about going vegan. In this regard, the “plants are sentient” argument is similar to the “Hitler was a vegetarian” argument so those concerned about animals are likely to be genocidal maniacs. First of all, Hitler was not a vegetarian. And even if he were, Mao and Stalin ate a lot of meat so any attempt to link genocidal conduct to diet is a nonstarter.

In sum, the “plants are sentient” argument is not about plants. It’s about nonhuman animals and it represents nothing more than a feeble and ultimately incoherent attempt to deny the moral imperative of veganism.

Originally published on Medium.com