Let's get this out of the way upfront: Drexel Environmental Philosophy Professor Andrew Smith isn't arguing against vegetarianism; rather, he's arguing vegetarianism doesn't even exist.

Hear him out.

A self-described vegetarian himself for nearly 20 years, he said he's also not defending meat-eating, so much as making the philosophical argument that, because plants, animals and humans are so inextricably linked on the food chain, it's impossible to be a vegetarian in the way we've come to conceptualize it. 

Here's what he wants you to know: The common defense of vegetarianism is that animals are sentient -- or feeling, perceptive -- creatures, but plants are not. Therefore, plants are an acceptable alternative food source. But after seeing a blog post speculating that plants could, in fact, perceive feelings, he began to rethink and research. Not to attack vegetarianism, but out of his own selfishness, to defend it.

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"I thought it might behoove me to try to create a stronger argument for vegetarianism that takes account of these facts," Smith told PhillyVoice. "Not to reject vegetarianism, but to say we need to provide a better defense of why we choose to eat what we eat, since plants have capacities – at least on my reading – that can lead us to believe they’re sentient."

His findings, then, led him to an altogether unexpected conclusion, detailed in his new book "A Critique of the Moral Defense of Vegetarianism," released last month through Palgrave MacMillan. 

Here, Smith puts on his thinking cap and explains the logic that inspired his writings.

To lay it out simply, how would you explain your argument that you can't be a vegetarian?

In a nutshell, we’re used to thinking of eating the plants that the animals we eat consume. Well, plants themselves eat animals – not directly in the way we ingest plants, but they ingest constituent parts of plants just like we digest and then live on the constituent parts of the beings we make food. The way I mention this in the book is eating is a transitive property. We are who we eat, our food is who our food eats, so we are who our food eats. Whether we eat animals or plants.

The biggest argument here that would have people confused is the idea that plants may be sentient. It’s hard to qualify a plant’s experience. How do you reconcile that?

I state very explicitly that to say plants are sentient is not to say they experience the world like humans do, or like sentient animals do. That’s simply not the case. We have overwhelming evidence they don’t experience the world like we do. We do generally classify ourselves as having five senses. Plants have somewhere in the neighborhood of 20 to 30 senses, and they’re constantly surveying the world around them. When we’re in danger, our pain receptors flare up and triggers the fight-or-flight mentality. We can run away; plants can’t. They do have other ways to not only seek out food through their roots and stems, but also to ward off noxious stimuli -- to ward off things that wound them. 

Smith: What I’m trying to show is we can extend the sorts of sympathies vegetarians have for animals to plants and to our ecological systems in general and do far better at the way we choose to treat those who we make our food in the process.

And here is the real kicker. If they feel pain -- and I nowhere claim they do -- then I argue this: If they feel pain, it’s not like we do. But what gives me the sense there’s good reason to explore that they have pain, is that when they are wounded they excrete a chemical called the endogenous opioid. And like opiates humans take for pain, like Percocet, or heroin illegally, these things dull pain. Plants excrete the same sort of chemical when they’re wounded. 

This suggests to me that we should, at least, be alive to the fact they’re trying to dull something we would otherwise classify as pain. This is worth exploring further. That, in combination with the very clear awareness of the world around them, and the way they interact with the world, leads me to suggest there’s enough scientific evidence to lead us to explore further the idea they’re sentient, and there's good reason, philosophically, to accept this claim.

What do you think it is about this subject that gets people riled up? There were some pretty fiery comments on the Drexel news blog that announced your book.

I think there are a couple things. The main thing is, I’m guessing vegetarians, in particular, looking at the array of comments, it’s clear to me vegetarians are reading this as an attack against their chosen lifestyle, their moral grounds for eating as they do. I’m not attacking anyone’s moral choices. What I’m trying to show is we can extend the sorts of sympathies vegetarians have for animals to plants and to our ecological systems in general and do far better at the way we choose to treat those who we make our food in the process.

You do call vegetarianism 'morally indefensible' in the book. I can see why the language would frustrate people.

It’s morally indefensible and that, and the title of the book, are really attention-grabbers, and my hope is it will get people to want to read the book and once they check out the first chapter they’ll hopefully see there’s more to what I’m saying than the standard, old sort of ‘vegetarianism versus carnivore’ boxing match.

You open the book saying we’re 'ecocidal.' Can you explain that?

We’ve heard of genocide, suicide and homicide, and what our culture engages in is ecocide: the destruction -- the killing -- of ecosystems. And part of what keeps us destroying ecosystems is the continued push for more food. Whether it’s plant food, plant-based food or meat, what’s happening is we’re eating up more of the world. My concern is to reorient how we think about the way we relate to our food, to open our eyes to the fact that part of what’s causing us to destroy ecosystems is the way we view our food and the relationship with our food. It gets into bigger concerns about sustainability and environmental consciousness, starting from what seems like a very small concern over the choice of what we eat and how we make those choices.

You also talk about excrement. You write, "... as odd as it may be, one of the main reasons that I have not committed suicide is intimately tied to s***," talking about the value of waste as nourishment to nature. That's pretty attention-grabbing, too.

I don’t know if I made the mistake of starting a class I now teach regularly by covering this taboo topic, but it’s sort of become fixed in this course and it’s a way of opening students up to the idea that something that’s very -- I stay away from ‘natural,’ but it’s something all of us have to do but also something the rest of the world needs. Human waste and waste of all creatures, itself is food for other creatures that our ecosystems require in order to stay healthy. And all of us are eaters, and all of us are eaten. You and I are being eaten now and thank goodness we are – our skin is covered with little mites that eat dead skin and hair follicles, and that keeps our skin healthy. We should be thankful for that and even more thankful that billions of bacteria in our digestive systems that allow us to metabolize everything we eat. 

We live in a world where eaters and the eaten are so intertwined and connected that the death of one creature and life of another sort of are coexistent. And this gets lost when we start to think about just deciding whether to eat plants or animals. 

Let’s assume you're right. What’s the ‘So what’? What does it change in a practical sense for someone vegetarian or not vegetarian?

Let’s think of the vegetarians here, who are likely to be those most concerned about this. The old argument is the idea that animals are sentient and plants are not. I want to suggest that for people who are compelled by that idea, this doesn’t mean it’s OK now to eat animals because plants are sentient. I think there’s still good reasons still not to eat animals; all this means is there are better and worse ways to be vegetarians. One better way to be a vegetarian, in order to do less harm if that’s our rubric, is to take plants’ needs and concerns into account. There are pretty obvious ways to do that. One way is to scale back the amount of industrial-conventional farming we do and in its place engage in organic farming. Plants simply do better when they’re raised organically than they do when raised with petrochemicals. We do better in turn, but even if we just focus on the plants, they’re much healthier in that respect. 

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We can speculate -- but I don’t feel we have to speculate -- about whether they’re happy or not. I don’t feel like going there. Just going on the healthier kick, it seems to suggest organic agriculture, farmers, agriculturalists who are able to care more closely for their plants instead of working on these huge acres of property where plants are really just commodities, do better. Smaller farms that existed everywhere in the world, even in the U.S., only 40 or 50 years ago. All I ask is that we consider some of the food policies we’ve made very recently and think about what that means for us and the beings who we make our food.

And, we can accept a form of vegetarianism that takes account of plant sentience and still do much better by plants.

What do you most want people to understand about what you’re saying and your book?

That’s a good question. I haven’t mentioned that the book is essentially weighing out three different arguments. The first is a defense of plant sentience; the second is a defense of place-based eating – you could call it ecological eating; the third is the argument that one can’t be a vegetarian. 

What I’d like to stress is readers can stop at any one of these steps and accept the conclusions without going on if they so desire. If they want to read on and find they disagree with me, that’s fine too, they can fall back on an earlier step they accept. If more people were to simply treat the plant world better, I would be the most thrilled person in the world. Whether or not they embrace my further arguments.

Below is an excerpt from the Preface of "A Critique of the Moral Defense of Vegetarianism," courtesy of Andrew Smith and Palgrave Macmillan.

'A Critique of the Moral Defense of Vegetarianism': The Preface

For the record, I did not expect to end up as an iconoclastic vegetarian when I began work on this project. I had no intention of even writing a book when I first set out, let alone a book in which I would challenge some of my own most entrenched beliefs. The development of A Critique of the Moral Defense of Vegetarianism has proceeded so quickly that it will take some time for me to fully digest (pun intended) what I have written here.

A Critique of the Moral Defense of Vegetarianism comprises two stories, one of exploration and the other of discovery. Initially, I set out to answer a question that occurred to me as I read through the comments of a blog post on the website of a divisive figure in my field. The author of the post suggested that omnivores, not vegetarians, bear the burden of justifying their dietary practices because omnivorism causes far more suffering and harm than vegetarianism does. Among the numerous responses to the post were several comments that focused on whether or not plants could suffer. They initially were offered in support of a sorry trope that vegetarians are forced to address ad nauseum. Namely, vegetarians are hypocrites because they condone killing and eating plants but proscribe killing and eating animals. In reply came a flurry of responses, including several in which it was (expectedly) emphasized that animals have the capacity to suffer — and in fact suffer greatly as a result of practices that are common today — when raised and killed for food. Plants do not, the respondents claimed. After all, in contrast to animals, plants are not sentient. This is a default assumption maintained by just about everyone who weighs in on the subject, whether in the philosophical literature or in the popular press. And since good reasons can be offered even to avoid killing animals painlessly for food, the charge of hypocrisy gets deflected.

I wondered, though, how the defense of vegetarianism would have to change if plants actually were sentient. I also questioned if I was warranted in presupposing without any real evidence that plants are not sentient in order to defend my own vegetarianism. So I dove headfirst into a body of scientific literature by researchers who study what has come to be called “plant neurobiology” and was amazed—stupefied—by what I found. When I say I was stupefied, I mean that I felt very stupid. Dumbstruck. There is a great deal of empirical evidence to support that plants are indeed sentient. This means that a common moral defense—my go-to defense—of vegetarianism fails, as I address in chapter 2. So I went ahead and developed an alternative defense and thought I had a halfway decent journal article on my hands.

The thing is, I have trouble separating my research from my personal life. And I am getting worse at doing so as time goes on. I have developed the habit of processing my own baggage through my professional writing. So it wasn’t enough that I had what I thought was a publishable essay. I had to spend much more time considering how my own practices would have to change. This is when things got complicated, when cracks in my self-understanding and sense of my place in the order of things began to appear. I realized that the new and better defense of vegetarianism that I had developed still was not good enough. I faced bigger, much bigger, problems. That my problems were—are—much bigger did not necessitate a particularly long book. Sometimes even complex issues can be unpacked fairly expeditiously. My difficulties at this point instead have to do with implementation, with actually heeding my conclusions. But I suppose this puts me in good company with quite a few past and present philosophers. 

So that is the beginning of my story of exploration. I invite you to continue reading if you would like to see the plot unfold. I now provide a brief sketch of my story of discovery — a story whose development has been even more surprising to me than my story of exploration. It also is a very personal story, more for me than for you to be honest, that I had no idea I needed to tell. No, that is not quite right. I was not aware that there was anything to tell until my initial article-length project began to morph into a book.

In November 2007, the day after I defended my dissertation, my maternal grandmother died. I did not visit my Grandma Hawman all that often. Even as a child we lived a daylong car drive from her home in eastern Pennsylvania. But she nevertheless was a powerful figure in my life. She was the genuine matriarch of my mother’s large family, and she represented something of an anchor for me. This is hard for me to explain, because it is hard for me to understand. Permit me simply to say that I felt deeply connected to her. The world at least made some sense as long as I knew I could enjoy a warm afternoon chatting with her on her front porch or spend an evening with her playing card games. 

Then she was gone. I went from the high of my dissertation defense to her funeral in a matter of days. And I never properly processed her death. I am not sure I ever mourned her loss, although I did not realize this until my story of discovery associated with this book began. All I can say is that I have been at sea in a number of ways since she passed away, and I did not realize just how much her death contributed to this. I am happy now to be piecing things back together. And while my discovery is in no way a final piece of the puzzle, it most assuredly is an important one.

I now live in Philadelphia just a stone’s throw from the beautiful Schuylkill River. I run almost every day in Fairmount Park along its banks. I love this place. The city has been very welcoming, for which I am so thankful. And no part of it has been more welcoming than the Schuylkill. Now I know why. You see, my Grandma Hawman is buried in a cemetery upstream in Reading that also is a stone’s throw from the Schuylkill. Yes, that is right. All along, it has been my grandmother, who is now interlaced with the river, who has been so welcoming. I did not, could not, see this for years. And while our connection is incomplete for reasons that I explore later, I finally have begun to mourn her death. Because I now see that she was never gone. I hope this makes more sense as the book unfolds.

Oh, and I have one more thing to mention about my Grandma Hawman. I never told her that I was a vegetarian. I thought she would not understand, that she would find it difficult to know how to feed me when I visited. So I strategically scheduled visits to avoid meals! The thing is, I now see that I had much more to learn than she did. And I have learned a lot in writing this little book. I hope that you do too. I look forward to hearing what you have to say about it.