And a hit is blood in the water for scribblers seeking popular subjects to elucidate. Thus the book's swift dismissal by mainstream science hasn't deterred food writers such as Michael Pollan from resurrecting the Nixon-era volume and noting, as he did last year in The New Yorker, that TheSecret Lives of Plants "had made its mark on the culture" — as if that qualification alone (people were hooked!) is a legitimate reason to exhume the idea and re-explore its highly suspect merits.
It's not, of course. In fact, the spate of recent media attention on the potential emotional lives of plants is — as I see it — little more than pandering to basic scientific illiteracy through semantic sleights-of-hand. Very recently (in light of this trend) several dozen leading plant scientists sought to set the record straight. They rejected the idea of plant intelligence altogether, noting that "there is no evidence for structures such as neurons, synapses, or a brain in plants."
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Undeterred, Pollan (who quotes this disapproving assessment in his article) nonetheless plowed ahead with a New Yorker-feature's worth of ink on the possibility of plant intelligence because "there will probably always be a strain of romanticism running through our thinking about plants." In other words, there's no proven merit to this half-baked idea — and he quotes a bevy of scientists saying as much — but, what the hell, if people are just moony enough to think there is let's leave it on the warming rack.
To be fair, Pollan — who is fully aware that The Secret Life of Plants was crackpot science — reminds us of something important: the underlying notion of plants being intelligent, or having feelings, isn't made out of whole cloth. Plants can be remarkably responsive to external stimuli in a way that might seem reflective of situational decision-making. In his recent book What a Plant Knows: A Field Guide to the Senses, plant scientist Alan Chapelski demonstrates that plants possess far more complicated sensory mechanisms than we've typically appreciated. These mechanisms enable plants to behave in ways that approximate the human understanding of smelling danger, sensing weather, and maybe even responding to noise. There's now no question that plants, as Chapelski said in an interview, "are complex organisms that live rich, sensual lives." So there is that. A plant, we should all agree, is more neurologically relevant than a shoe.
But to exploit these findings to suggest that plants really "think" or have "feelings" in the vertebrate sense is a different matter altogether. Making this move — one that seriously asks us to compare the sentience of a pig and a pumpkin — requires either distorting the nature of thought and feeling beyond recognition or making a leap in logic no different than global warming deniers make when they suggest that the atmosphere — you never know — would have warmed without anthropocentric influence.
Chapelski, for one, knows better than to go there. "Plants exhibit elements of anoetic consciousness which doesn't include, in my understanding, the ability to think," he has said. "Just as a plant can't suffer subjective pain in the absence of a brain, I also don't think that it thinks." Which brings us back to the original question: Why have so many journalists picked up on a renegade hypothesis — one without a shred of hard evidence — and unleashed the idea that plants might be sentient, intelligent beings?
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A pretty good hint of an answer comes from a tweet Pollan put out some time ago. Commenting on an article that described how plants communicate, he alerted the masses, "Cool piece on how pea plants communicate with one another, possibly raising some tough issues for vegetarians." Emphasis mine.
Pollan was kidding. But still, he raises a point that less judicious critics of vegetarianism embrace: plant sentience, if a reality, undermines the vegetarian ethic. Vegetarians choose to avoid eating animals because animals suffer to become food. In turn, they replace animal flesh with plant-based food. But if plants suffer as well as animals, the vegetarian can no longer claim the moral high ground. His pedestal gets kicked to the curb.
For conscientious carnivores — a rarified band of gourmands who reject industrial animal agriculture but refuse to give up eating boutiquely rendered animal products — plant sentience would once and for all shut down those nagging animal rights creeps who ask: "How do we grant animals moral standing and still eat them?" Pollan, who has struggled with this question, would certainly breathe a sigh of relief.
If my argument here is right — that is, if the foodie emphasis on intelligent plants is little more than curiosity obscuring ideology — there's still something for vegetarians to learn from the challenge, disingenuous though it might be.
For one, as the concept of plant intelligence circulates, vegetarians would be wise to seek a solid, no-nonsense response to it. It won't do to simply say, "That's crazy talk, man!" The best bet on this score is an excerpt from Oliver Sacks, who elaborates the fundamental distinction between plants and animals in evolutionary and cellular terms. Focusing on the speed with which ions move though ion channels across synapses in plants and animals — thereby allowing thought — he explains:
The calcium ion channels that plants rely on do not support rapid or repetitive signaling between cells; once a plant action potential is generated, it cannot be repeated at a fast enough rate to allow, for example, the speed with which a worm 'dashes … into its burrow.' Speed requires ions and ion channels that can open and close in a matter of milliseconds, allowing hundreds of action potentials to be generated in a second. The magic ions, here, are sodium and potassium ions, which enabled the development of rapidly reacting muscle cells, nerve cells, and neuromodulation at synapses. These made possible organisms [i.e., animals] that could learn, profit by experience, judge, act, and finally think.
The second (and more controversial) thing vegetarians might do (after figuring out Sacks' explanation) is, given the intelligent plant push, to take the proposition of sentient life in the other direction — into the animal kingdom — and ask if the criterion of sentience denied to plants should also be denied to certain animals.
After all, basic intellectual honesty demands that humans acknowledge that animal life is spread across a continuum of emotion and reason and, in turn, that our moral consideration of animals depends in part on where they fall on this spectrum. Oysters and insects come to mind as possibly fair game for ethical consumption. Look at it this way: Without technical vegetarians to pick on, maybe the advocates of plant brilliance would stop reaching for straws and, instead, take a closer look at the animals that we know for sure possess intelligence and, when they are raised to feed us, suffer.
