the b12 deficient

Do Plants Feel Pain?

So, this article was originally conceptualized as a zine, a few months back, under the banner "The B12 Defizinecy". So cool. The zine was supposed to be an explainer about issues where I myself am not completely sure where I stand. So the end goal would be to separate the wheat from the chaff, to clear my own understanding of the matter and hopefully educate you too. But I'm giving up on the zine concept, for now. Need to improve my writing skills first.

Here, I had set out to prove that plants don’t feel pain. It was triggered by a glut of news articles reporting on an Israeli scientist group’s research.

Please note that the work presented here is not completely original, I have lifted heavily from external sources, sometimes copying verbatim. I’ve cited these sources wherever I could. This is meant to be an explainer, a compilation of the information that is readily available. I don’t intend to be making any money out of this.

“Turns out plants scream out in pain too: All those committed to browbeating consumers of animal products into giving them up would now have to admit that even the plant-based alternatives they recommend aren’t exactly consistent with the “cruelty-free” lifestyle. Because, if plants too feel pain and thirst in the way that the so-called higher life forms do, then no choice — not vegetarianism nor veganism — is truly “cruelty-free”. Telling someone to replace their actual steak with a “cauliflower steak” may once have been easy. But would that still be the case after knowing that the cauliflower wailed in pure agony when it was harvested? The moral high ground is starting to look like a more level place.” - Indian Express Editorial dated 6 April 2023 [1]

“This is what a plant sounds like when it’s stressed: Listening to their distress calls could one day save water and help farmers …... Farmers could set up listening sensors to gauge whether their crops are healthy or need extra attention. ….. And since they could potentially hear how dry the plants are — whether they’re just starting to get dehydrated or nearing the point of no return — this kind of application could help farmers water crops more efficiently. Climate change is intensifying droughts in many places around the world, and crop yields are expected to suffer as a result. Precision irrigation could conserve up to 50 percent of the water farms use, the paper notes, while still producing more bountiful harvests.” [2]

“Plants emit ultrasonic ‘distress screams’ when stressed: The researchers suspect that the sounds are generated by a process called cavitation — where air bubbles form, expand and explode in the xylem causing vibrations. “Cavitation explosions have been shown to produce vibrations similar to the ones we recorded,” they write.” [3]

I find it strange that people will find the cutting of a tomato to be the same as slitting the throat of a pig? Not talking about cops here. The depths that a person can stoop down to, in order to justify the murder and rape of sentient beings that suffer and feel pain, has no bounds. The sheer cognitive dissonance of online “leftists” who talk about bringing a revolution but can’t make a simple lifestyle change to end the suffering that they contribute to directly is abhorrent.

Let us explore the research paper that has triggered this explosion of news articles everywhere. Sounds emitted by plants under stress are airborne and informative [4]. The authors are quite clear, in the first paragraph itself, about what they have set out to do here:

And that is the premise. Nothing about pain or agony. Nothing new in terms of the vibrations themselves either. They say that they suspect that it might be due to “cavitation”, and cite papers from 1989 and 2013. These processes are not new. Previously, people have put their microphones right next to the stem of the plant to study these vibrations. Milburn and Johnson, in 1966, detected sounds coming from a plant/leaf subjected to drought conditions [5].

It is important to understand the new knowledge that has been unearthed from this study in particular. The scientists, by putting their microphones at a further distance, have discovered that the sounds are airborne. The rest of the paper is about how a “machine learning model” can distinguish between these sounds accurately.

The news articles deliberately mislead the reader about how the researchers have discovered that the plants are screaming in distress, and the above context is rarely ever provided anywhere.

What is Cavitation?

Cavitation is a process where air bubbles form in the xylem in drought conditions. Upon transpiration of water from the leaves, a tension is developed at the site of the evaporation. This negative pressure enables the transportation of water through the xylem. This process is dependent, among other things, on the pressure of the water in the soil. When the soil is dry, a high negative pressure is developed, leading to a sudden phase change of the water in the xylem to water vapour [6].

If you feel that this technical lingo is a tad complicated, here is how I understood it. When water evaporates from the stomata, a suction a created at the leaf. This results in the water in the xylem to move upwards to fill in that gap, while water from the soil replaces the water in the xylem. However, if the soil is dry, there will be a pressure from that end also. This increased negative pressure on the water from both sides results in the water becoming vapour. This process, along with the subsequent expansion or contraction of the air bubbles, is said to cause the clicking sounds at ultrasonic frequencies.

A purely mechanical process that is easily explained by physics, with no reference to suffering, pain or distress.

However, it should be noted that some researchers believe that not all sounds emanating from plants can be explained by cavitation. While different theories are floating around, it is clear that more research would be required into this phenomenon. It should be also be noted that no evidence has been found thus far of the plants actually having receptors for perceiving sound [7].

Isn’t it strange that people will justify boiling lobsters alive by saying that it’s just air escaping their lungs or whatever? But when it comes to plants, the same people will readily believe that the tomatoes are screeching their lungs out in distress, begging their human overlords not to eat them.

Do Plants Feel Pain?

The majority of this section is a summary of the research paper titled “Do Plants Feel Pain?” by Adam Hamilton and Justin McBrayer. Go read the original article. [8]

Moral patiency: A moral patient is a being whose owed some sort of moral consideration from the rest of us. There is a difference between a person kicking a dog, and a person kicking a rock. Why? Because the dog can experience pain, pleasure and other mental states/ emotions, which a rock cannot. Dogs are sentient. There is something it is like to be a dog, but nothing it is like to be a rock. How do we define this more clearly? Phenomology is the philosophical study of subjective experiences. So to have multiple phenomenal states would mean that we can distinguish between and enjoy the taste of different foods, smell different flowers, hear and understand sounds etc. When we say “what it is like to be something”, we would mean that there is something that it is like to be being with a mind in this phenomenal sense.

Do we know what it is like to be a plant? Are plants sentient?

How do we know that other beings (human beings, non-human animals, or otherwise) may be experiencing the same things as us?

Non-human animals share similar nervous systems to human beings, which behave in the same manner, and elicit the same response as a human being would, when subjected to circumstances which would elicit pain in human beings. If plants have a mind and experience life in the same way, then we should be able to provide evidence for the same using the methodology described above.

The first method is useless, because there is no common language for a plant to give testimony to us. While we may have uncovered some evidence of plants “communicating” with each other with the help of some signals, testifying requires a proper language. There is no way to get a testimony from a plant, and hence we move on to the other three.

Plant behaviour

This is the most interesting of the bunch. Much has been said about the behaviour and intelligence of plants. The screaming tomatoes are an obvious example. Similarly, plant leaves have been known to “listen” to caterpillars chewing on their leaves, and reacting accordingly. Sunflowers move their heads to follow the sun. The venus fly trap which snaps shut when the hairs on its surface are triggered. The touch me not leaves which don’t like to be touched. There is the fungus which connects the roots of entire forests, and enables the transfer of resources from plants which have a surplus to the ones in need (the scientific name of the fungus is vlamdirus leninus and this phenomenon is also referred to as “plant communism”).

From all the above examples, we can say that plants are quite intelligent, as they regularly indulge in behaviours which may be classified as signalling behaviour, stimulant-avoidant behaviour, sustenance-seeking behaviour, etc. But intelligence itself is not an indicator of moral patiency. Computers are much better than humans at games like chess and Go, but that does not mean we can ascribe phenomenal consciousness, or sentience to them. Is the iPhone a sentient being then? The venus fly trap can’t even distinguish whether the item kept between its jaws is a suitable prey or not.

Some might argue that stimulant avoidant behaviour is evidence of pain. Stimulant-avoidant behaviour is not necessary for pain, because a being could a being could hold the pain in, and not change its behaviour. Stimulant avoidant behaviour is not sufficient for pain either, because it can be faked. Both these instances are evolutionarily beneficial. An animal, can ignore its pain to escape a predator, or behave as if it not affected by the pain to impress another individual. Similarly, it can choose to lie and engage in such behaviour even though it is not required. It is not enough to show that at least some plants exhibit some behaviour that may be broadly classified as stimulant avoidant, because that is not an indicator of pain.

A self-driving car may choose to stop the car upon sensing an emergency situation, but that is proof that it is doing so in order to escape the sensation of pain. A car is aware if its door is open, whether the driver is wearing a seatbelt, it can activate airbags in case of an accident, but such actions don’t require consciousness. In our own body, an organ such as the pancreas simply releases insulin upon detecting high blood sugar, that does not make it sentient.

Plant evolution

The evolutionary trajectory of plants and animals diverged long before nervous systems were even a thing. An estimate of the divergence of plants, animals, and fungi put the separation of the kingdoms around 1,576 million years ago. In contrast, humans diverged from chimpanzees roughly 6 million years ago

Animals are mobile and have complex social lives. Plants are stationary, and rely on their fruit being eaten in order to reproduce. Their evolutionary strategies to deal with the environment are entirely different. Just from an evolutionary perspective, it does not make sense that plants have independently developed a system to process pain and other emotions. It would not increase their chances of survival at all. It would in fact be harmful to plants, in terms of the amount of resources it would take up for an immobile being like plants (the brain takes up a majority of the body’s calories and oxygen, and both the brain and central nervous system are encased in bone).

Plant anatomy

Plants don’t have a brain, and they don’t have a central nervous system, they don’t have nociceptors (nerve cell endings that initiate the sensation of pain). End of discussion. Despite far-fetched theories proposed by certain “scientists”, “there is no evidence for structures such as neurons, synapses, or a brain in plants.

The Utilitarian Argument

If we actually cared about plant lives and the net impact of the suffering that humans are causing, then going vegan would still be the best way forward because majority of the deforestation happens due to animal agriculture, and the majority of the crops grown go towards animal agriculture. All of the diagrams below have been picked up from the website ourworldindata.org [9].

Conclusion

Plants don't feel pain. Go vegan.

Bibliography

[1] Indian Express Editorial, "Express View: Turns out plants scream out in pain too," 06 April 2023. [Online]. Available: https://indianexpress.com/article/opinion/editorials/express-view-turns-out-plants-scream-out-in-pain-too-8540950/.

[2] J. Calma, "This is what a plant sounds like when it’s stressed," 01 April 2023. [Online]. Available: https://www.theverge.com/2023/3/31/23664767/plant-sounds-stress-tomato-tobacco-research.

[3] R. Prasad, "Plants emit ultrasonic ‘distress screams’ when stressed," 14 December 2019. [Online]. Available: https://www.thehindu.com/sci-tech/science/plants-emit-ultrasonic-distress-screams-when-stressed/article30306754.ece.

[4] I. e. a. Khait, "Sounds emitted by plants under stress are airborne and informative," Cell, vol. 186, no. 7, pp. 1328-1336, 2023.

[5] G. Jackson and J. Grace, "Field measurements of xylem cavitation: are acoustic emissions useful?," Journal of Experimental Botany, vol. 47, no. 304, pp. 1643-1650, 1996.

[6] H. e. a. Cochard, "Methods for measuring plant vulnerability to cavitation: a critical review," Journal of Experimental Botany, vol. 64, no. 15, pp. 4779-4791, 2013.

[7] D. S. F, M. V, F. L and A. L, "Is There a Role for Sound in Plants?," Plants (Basel), vol. 11, no. 18, p. 2391, 2022.

[8] A. Hamilton and J. McBrayer, "Do Plants Feel Pain?," Disputatio, vol. 12, no. 56, pp. 71-98, 2020.

[9] [Online]. Available: ourworldindata.org.