Plant Pain?

"The question is not, Can they reason? nor, Can they talk? but, Can they suffer?" - Jeremy Bentham
LJM1979
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Plant Pain?

Post by LJM1979 » Mon Dec 10, 2012 2:29 pm

I know most who raise this topic are dismissed as silly or confused but I'd like ask what implications follow if you assign a nonzero probability to the existence of plant sentience? Even if it's extraordinarily unlikely - let's say one in a trillion odds - that plants feel pain, I'd think the expected value of their pain would be substantial due to their prevalence. You would have to know the "location" (for lack of a better word) of the subjective experience in order to do an expected value calculation (e.g., does each root feel pain? each leaf? or just the whole plant?) I know the usual criticisms of the notion of plant sentience (no known mechanisms could produce it; what evolved function would it serve?, etc) but I don't think we know enough about sentience or consciousness to say that it is impossible for any entity to have such subjective experiences (i.e., you have to assign a nonzero possibility).

Does a nonzero probability of plant sentience change the debate on whether there is a predominance of suffering in nature? Or what diets are most justifiable? Or even whether the continuation of the human species is justifiable?
Last edited by LJM1979 on Wed Dec 12, 2012 1:06 pm, edited 1 time in total.

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Hedonic Treader
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Re: Plant Pain?

Post by Hedonic Treader » Mon Dec 10, 2012 4:26 pm

LJM1979 wrote:let's say one in a trillion odds
It's considerably higher. All you need to make a low-probability case for plant pain is evidence of functional plant movement in response to integrity damage, and corresponding movement-controlling information processing of some sort. This movement doesn't have to rely on muscles, the controlling doesn't have to rely on neurons, and they don't have to be fast.

However, if you want to address high-stakes low-probability cases of natural suffering, studying insect suffering should take precedence.
"The abolishment of pain in surgery is a chimera. It is absurd to go on seeking it... Knife and pain are two words in surgery that must forever be associated in the consciousness of the patient."

- Dr. Alfred Velpeau (1839), French surgeon

LJM1979
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Re: Plant Pain?

Post by LJM1979 » Mon Dec 10, 2012 5:09 pm

Hedonic Treader wrote:
LJM1979 wrote:let's say one in a trillion odds
It's considerably higher. All you need to make a low-probability case for plant pain is evidence of functional plant movement in response to integrity damage, and corresponding movement-controlling information processing of some sort. This movement doesn't have to rely on muscles, the controlling doesn't have to rely on neurons, and they don't have to be fast.

However, if you want to address high-stakes low-probability cases of natural suffering, studying insect suffering should take precedence.
Why? Aren't there far more plants than insects?
You mean considerably higher as in *more* probable than one in a trillion, right?

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Re: Plant Pain?

Post by Hedonic Treader » Mon Dec 10, 2012 5:24 pm

LJM1979 wrote:Why? Aren't there far more plants than insects?
Yes, but the probability of insect suffering is a lot higher than that of plant suffering, there are also very many insects, and it might be easier to study. OTOH, maybe identifying candidate functions for suffering in plants might be possible.
You mean considerably higher as in *more* probable than one in a trillion, right?
Yes, it's very low but not 10^-12.
"The abolishment of pain in surgery is a chimera. It is absurd to go on seeking it... Knife and pain are two words in surgery that must forever be associated in the consciousness of the patient."

- Dr. Alfred Velpeau (1839), French surgeon

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Re: Plant Pain?

Post by LJM1979 » Mon Dec 10, 2012 8:19 pm

Hedonic Treader wrote:
LJM1979 wrote:Why? Aren't there far more plants than insects?
Yes, but the probability of insect suffering is a lot higher than that of plant suffering, there are also very many insects, and it might be easier to study. OTOH, maybe identifying candidate functions for suffering in plants might be possible.
You mean considerably higher as in *more* probable than one in a trillion, right?
Yes, it's very low but not 10^-12.
Do you think we ever will know whether plants or insects suffer? I'm highly skeptical, but without knowing which forms of life are sentient, we'll never be able to maximize or even know how to maximize well-being. For example, several have argued compellingly (Oscar Horta, Brian Tomasik) that there is net suffering in nature. Robert Wiblin actually argues that destroying nature might be the most practical solution (http://robertwiblin.com/2010/01/21/just-destroy-nature/)
Yet, if plants can feel pain and if they on average have net positive lives, that changes all our thoughts about the utility of nature. Because plants are so numerous, if they have net positive existences in any meaningful psychological sense, it could be that more positive affect exists in nature than anywhere else. So we have two diametrically opposed implications depending on whether insects, plants, neither, or both are sentient (destroy nature vs. promote it everywhere). Without any way of knowing which forms of life are sentient, I don't see how we can ever know how to maximize utility, and it's not clear to me that we can ever have more than "educated guesses" about which forms of life are sentient.

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Re: Plant Pain?

Post by Hedonic Treader » Tue Dec 11, 2012 10:06 am

LJM1979 wrote:Do you think we ever will know whether plants or insects suffer?
Maybe the right way to do it is to scientifically analyze our own pain as accurately as humanly possible, and then look for crucial similarities and dissimilarities in those other information-processing systems.
"The abolishment of pain in surgery is a chimera. It is absurd to go on seeking it... Knife and pain are two words in surgery that must forever be associated in the consciousness of the patient."

- Dr. Alfred Velpeau (1839), French surgeon

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Re: Plant Pain?

Post by LJM1979 » Tue Dec 11, 2012 1:31 pm

That's probably the closest we can come to answering the question. It assumes though that the same mechanisms that produce human consciousness are the only ones that could produce consciousness in other living beings.

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Re: Plant Pain?

Post by Hedonic Treader » Tue Dec 11, 2012 2:02 pm

It doesn't have to assume it's the same mechanisms, just mechanisms similar enough that you can identify them. If you have no reason to assume consciousness in any other entity, then you shouldn't assume consciousness (principle of parsimony).
"The abolishment of pain in surgery is a chimera. It is absurd to go on seeking it... Knife and pain are two words in surgery that must forever be associated in the consciousness of the patient."

- Dr. Alfred Velpeau (1839), French surgeon

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Re: Plant Pain?

Post by davidpearce » Tue Dec 11, 2012 6:24 pm

If Strawsonian physicalism (cf. http://en.wikipedia.org/wiki/Physicalis ... hysicalism ) is true, then fields of micro-experience may be ontologically fundamental. But this doesn't mean we need to start worrying about the subjective well-being of sticks, stones or plants. This is because such composite entities are mere structured aggregates - not unitary subjects of experience . (cf. http://en.wikipedia.org/wiki/Mereological_nihilism )

What are the necessary and sufficient conditions for the generation of a unitary subject of experience? In short, we don't know. No one really understands how the brain solves the binding problem. (cf. http://lafollejournee02.com/texts/body_ ... inding.pdf )
Why aren't 80 billion odd (apparently) discrete, membrane-bound classical nerve cells just interconnected patterns of "mind dust"? My own idiosyncratic conjecture combines Strawsonian physicalism with macroscopic quantum coherence, but on quantum mind sceptic's Max Tegmark's sub-picosecond decoherence timescales rather than Stuart Hameroff's milliseconds. True or false, the challenge of unifying membrane-bound nerve cells into bound phenomenal objects or a unitary subject of experience pales into triviality compared to the challenge of unifying cellulose-encased plant cells. For a plant mind hypothesis to work, we'd need to abandon reductive physicalism in favour of a pre-scientific animism. Recall too that we do know precisely how to switch off phenomenal pain altogether in humans, namely induce nonsense mutations of the SCN9A gene.
( http://www.nature.com/nature/journal/v4 ... 05413.html )
Plants lack a SCN9A gene - or any homologous (or indeed analogous) gene. So I think herbivores can eat cabbages and lettuces with a clear conscience!

From my experience, the "problem" of plant pain arises only because meat eaters seeking to rationalise their habit cast around for some sort of "We're-all-guilty-so-none-of-us-are" excuse and start feigning compassion for vegetables.

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Re: Plant Pain?

Post by LJM1979 » Tue Dec 11, 2012 7:56 pm

Wow, thanks for all the detail. I am going to spend some time reading through those sources you've cited.
I agree that most people who raise the topic of plant pain do so because they want to continue eating meat but that argument is misguided on many levels. I probably shouldn't have even mentioned diet in the initial message.

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Re: Plant Pain?

Post by peterhurford » Tue Dec 11, 2012 10:26 pm

My personal prior probability that plants suffer is less than an order of a magnitude higher than my probability that sand grains suffer or that bacteria suffers, so I'd sooner worry about them.
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Brian Tomasik
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Re: Plant Pain?

Post by Brian Tomasik » Wed Dec 12, 2012 7:38 am

Good question, LJM1979! Coincidentally, I was thinking about this just a few days ago.

I haven't researched the number of plants in the world, though I would guess it's at least a few orders of magnitude more than the number of animals, especially if you count phytoplankton.

Hedonic Treader described well the case one might make for plant pain: "functional plant movement in response to integrity damage, and corresponding movement-controlling information processing of some sort." This seems like a far cry from consciousness, but given how little we know about these things, the probability is, as Hedonic Treader said, much bigger than 1 in a trillion.

Still, the probability is a lot lower than for insects. Whether the reduced probability of plant sentience is enough to make expected plant pain lower than expected insect/zooplankton pain is unclear. Another consideration, as Hedonic Treader pointed out, is that plants respond much slower than animals, so maybe the effective clock speed for plants is (orders of magnitude?) slower than for animals, which might be enough to dampen out their otherwise potentially massive expected value.

I don't know if plants would have net positive lives in the wild. Like with animals, most plant offspring probably die soon after pushing out of their seeds. Only a lucky few mature to adulthood, I would guess. Plants can also have stresses due to hostile weather, lack of food, drought, being eaten alive by herbivores, etc.

So I'm personally doubtful about LJM1979's suggestion that plant sentience could reverse the balance of pleasure/pain in nature. At least it would add more uncertainty, but even a priori, it's not clear why we'd assume that plant lives are net good (especially since the lives of the organisms we do know about -- small, short-lived animals -- are probably net bad). Sure, plants look peaceful, but who knows what kind of stress, fear, or deprivation of basic needs is going on inside their "heads" (internal communication systems). (Yes, that sentence was mainly tongue-in-cheek with wording, but the point was serious. :) )

If plant lives aren't worth living, a lot of the interventions that we would support to reduce short-lived r-selected wild-animal populations would also reduce plant populations. Putting up parking lots, reducing plankton populations, palliating climate change, desertification, and land salination are things that tend to reduce not only animal populations but also plant populations. In general, a first-order approximation for the amount of animal life in an ecosystem is the amount of plant life, although it's possible this isn't always true. For example, eutrophication may increase plant biomass while decreasing animal biomass, but this suggestion remains counterintuitive and hence speculative.

As far as diets, the standard reply is that most meat production requires killing many times more plants than eating plants directly, so even if plants feel pain, it's better to be veg. This is probably true even when we consider wild animals because global warming will probably increase plant abundance in the long term.

Whether plants suffer or not also doesn't change the thrust of my futurism concerns: Terraforming, panspermia, and sentient simulations will create at least as much plant life as animal life.

All in all, the things I'm working on aren't much affected if plants are sentient. Regardless, the issue doesn't keep me up at night, and I haven't formally included it in my calculations. The reason may be because I might decide that I just don't care about the computations that plants do as being conscious suffering. I'm allowed to do this if I want to. :) Now, if you show that the operations that plants do is really similar to operations done by animals that I care about, I may change my mind, but I think it's pretty unlikely the correspondence will be that strong.

As far as David Pearce's comments, I hold a very different view. I don't believe there is a "hard" binding problem or that quantum mechanics is at all relevant. But I still agree with David on many things and owe a great deal to him; this is just a friendly intellectual disagreement. :)

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Re: Plant Pain?

Post by LJM1979 » Wed Dec 12, 2012 12:40 pm

Thanks; I think you do make a good point about plant sentience probably not reversing the balance of suffering/pleasure in nature. I probably was thinking of just the most salient plants (big, healthy ones) when I made that comment.

You're right that that is the standard reply to the diet question and I think it's a good enough reply to invalidate any "plant-pain" criticisms of veganism by meat-eaters.

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Re: Plant Pain?

Post by Ruairi » Wed Dec 12, 2012 10:52 pm

"I don't know if plants would have net positive lives in the wild. Like with animals, most plant offspring probably die soon after pushing out of their seeds. Only a lucky few mature to adulthood, I would guess. Plants can also have stresses due to hostile weather, lack of food, drought, being eaten alive by herbivores, etc."

However plants are evolutionary winners when eaten so this would feel good for them if they felt? (probably)

"My personal prior probability that plants suffer is less than an order of a magnitude higher than my probability that sand grains suffer or that bacteria suffers, so I'd sooner worry about them."

*like* :D!

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Re: Plant Pain?

Post by LJM1979 » Thu Dec 13, 2012 1:21 am

Ruairi wrote: 0
"My personal prior probability that plants suffer is less than an order of a magnitude higher than my probability that sand grains suffer or that bacteria suffers, so I'd sooner worry about them."

*like* :D!
I don't think that quote takes the notion of expected value seriously. Like me, you and Peter appear to assign an extremely low but nonzero probability to plant sentience. I don't mean to be a jerk, but it's not clear to me that you're taking that belief to its logical conclusion - or at least it's not clear to me why the expected value of total plant suffering in nature is low. If you have a very low probability but multiple it by an inconceivably high number (the # of plants in existence), it's still possible to come out with a meaningful value. I think Brian's answer about it complicating issues but not necessarily reversing the conclusion about a predominance of suffering in nature is helpful though.

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Re: Plant Pain?

Post by davidpearce » Thu Dec 13, 2012 5:16 am

Seemingly useless metaphysical debates can sometimes have profound ethical consequences. So I'm going to risk outlining my "philosophical" disagreements with Brian - even though ethically we agree on a lot!

IMO consciousness, for example a phenomenal pain, is concrete, possessing spatiotemporal location and causal efficacy; an algorithm is abstraction. I'm sceptical about any ultimate ontology of abstract objects (what might actually cause us to credit their existence?), even though, if we don't treat abstract objects as real for some purposes, we will miss many features of the real world. [Perhaps compare our understanding of functionalist / teleological explanations pre- and post-Darwin.] Thus natural selection has recruited e.g. pains to play, typically, an information-processing role in living organisms capable of self-propelled motion and capable of sustaining an energetically expensive nervous system. But neuropathic pain, for instance, that doesn't play any algorithmic or information-processing role in the organism is just as real as its "typical" counterpart. Consciousness, with or without any functional role, is not something mind/brains do: it's what they are.

Panpsychism? Presumably, we'll ultimately need rigorously to derive the phenomenology of our minds from the properties of the fundamental stuff of the world - a reductive physicalism with no strong emergence, i.e. no unexplained eruption into the world of something ontologically new, not expressible within the mathematical straightjacket of modern physics. I don't think panexperientialism / Strawsomoan physicalsm can do this, or rather not on its own. Hence the seemly intractable binding problem and the classically inexplicable existence of "bound" phenomenal objects and the (fleeting, synchronic) unity of consciousness - and the desperate-sounding proposals that quantum mind theorists have devised to overcome the problem. But I don't think any proposal to solve the binding problem consistent with reductive physicalism can even get off the ground unless we assume a pan-experientialist / Strawsonian physicalist ontology. Such an ontology is the precondition of a reductive explanation of phenomenal minds, not an explanation itself.

Two grounds for taking panexperientialism / Strawsonian physicalism seriously IMO are 1) the fundamental entities in theoretical l physics (fields / superstrings / branes ) are defined purely mathematically; their supposed insentience is an extra assumption, not integral to the physics. And (2) the only part of the world to which one had direct access, namely one's own mind/ brain , has precisely those attributes that the pan-experientiallost / Strawsonian physicalist claims - contrary to one's naive materialist or abstract pan-informationalist intuitions.

More to be said ? Yes, for sure. :-)

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Re: Plant Pain?

Post by Brian Tomasik » Thu Dec 13, 2012 8:52 am

Ruairi wrote: However plants are evolutionary winners when eaten so this would feel good for them if they felt? (probably)
Only for the fruit parts of plants. Most plants don't like it when their heads are chomped off -- they need to grow back, and if the damage is severe enough, they die. Many plants have toxins / thorns / etc. to try and prevent being eaten.
LJM1979 wrote: I don't mean to be a jerk, but it's not clear to me that you're taking that belief to its logical conclusion
Yeah, though there's a difference between plants/bacteria and sand grains. I mentioned it to Yew-Kwang Ng back in 2006, and he thought it was a good point. :) The idea is just that, for sand grains and other inanimate objects, we have no idea whether any given action would increase or decrease their welfare. For plants and bacteria, we could assume that harming them biologically might induce suffering (in the unlikely event they can suffer at all), but for sand grains, what would cause them to suffer? Does it hurt them if we step on them on the playground?

I may reply to good ol' David another day, but it's getting late for tonight. :)

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Re: Plant Pain?

Post by Ruairi » Thu Dec 13, 2012 5:37 pm

Also neuroscience will probably continue to explain sentience better and better without us taking action, but concern for sentients won't happen (as much) without us, and perhaps not at all for wild animals or artificial sentients (or perhaps for sand grains too! ;) ).

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Re: Plant Pain?

Post by peterhurford » Thu Dec 13, 2012 5:54 pm

LJM1979 wrote:I don't mean to be a jerk, but it's not clear to me that you're taking that belief to its logical conclusion - or at least it's not clear to me why the expected value of total plant suffering in nature is low. If you have a very low probability but multiple it by an inconceivably high number (the # of plants in existence), it's still possible to come out with a meaningful value.
There's also an inconceivably high number of sand grains or bacteria -- more so, I'd suggest, than plants. Thus, I'm more "concerned" about them.
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Re: Plant Pain?

Post by LJM1979 » Thu Dec 13, 2012 6:43 pm

peterhurford wrote:
LJM1979 wrote:I don't mean to be a jerk, but it's not clear to me that you're taking that belief to its logical conclusion - or at least it's not clear to me why the expected value of total plant suffering in nature is low. If you have a very low probability but multiple it by an inconceivably high number (the # of plants in existence), it's still possible to come out with a meaningful value.
There's also an inconceivably high number of sand grains or bacteria -- more so, I'd suggest, than plants. Thus, I'm more "concerned" about them.
Actually I think open-mindedness requires having some concern for the possibility that panpsychism (http://en.wikipedia.org/wiki/Panpsychism) is right and all matter has a meaningful psychological experience - even if we give it a very low probability. You've switched the topic from plants to nonliving matter but I don't think you've successfully addressed the concern of sentience in nature beyond the animal kingdom.

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