Philosophy Discussion Forums

Pattern-chaser wrote: ↑December 21st, 2020, 1:27 pm

Greta wrote: ↑December 19th, 2020, 3:20 pm What plants can't do is move. You will find that sessile organisms generally don't have nervous systems - neither plants nor animals, eg. sea sponges. That is because, if you are a sessile being, chances are that someone else is going to take a bite of you. If every bite is agony (as it is for brained animals), we must consider the common plant strategy of attracting animals to eat them so as to disperse their seed.

Plants do move, of course, but again, they do it much more slowly than we do. And they can't pick up their roots and walk, of course. But I think your focus on nervous systems is not quite right. We shouldn't be looking for an equivalent to a nervous system, but rather something equivalent to experiencing pain. As Mr Nagel says, we have no idea what it's like to be a bat, and rather less idea what it's like to be a plant. I don't think we should look for equivalents to human faculties, but for things that could function for plants like human skills do for us. Does that make sense?

Sure, you always make sense, just that I don't always agree with you. In lieu of overt responses in a vegetative state, we are to some extent forced to focus on structures rather than sensations, seeking equivalents to the structures that we know generate sensations in brained animals.

Maybe workshopping this would be helpful? To start, what use is pain and suffering? Why do very complex organisms (at least) hurt? But why? Why can't we just respond to stimuli without hurting? How could a sessile organism that experiences pain and suffering cope with the regular assaults that it can't deflect? The evolutionary pressures would seem to point to either being able to move, have a defence (thorns, chemicals) or to not feel pain.

Over to you ...

Pattern-chaser wrote: ↑December 21st, 2020, 1:27 pm Plants do move, of course, but again, they do it much more slowly than we do. And they can't pick up their roots and walk, of course. But I think your focus on nervous systems is not quite right. We shouldn't be looking for an equivalent to a nervous system, but rather something equivalent to experiencing pain. As Mr Nagel says, we have no idea what it's like to be a bat, and rather less idea what it's like to be a plant. I don't think we should look for equivalents to human faculties, but for things that could function for plants like human skills do for us. Does that make sense?

Greta wrote: ↑December 21st, 2020, 7:49 pm Sure, you always make sense, just that I don't always agree with you. In lieu of overt responses in a vegetative state, we are to some extent forced to focus on structures rather than sensations, seeking equivalents to the structures that we know generate sensations in brained animals.

Maybe workshopping this would be helpful? To start, what use is pain and suffering? Why do very complex organisms (at least) hurt? But why? Why can't we just respond to stimuli without hurting? How could a sessile organism that experiences pain and suffering cope with the regular assaults that it can't deflect? The evolutionary pressures would seem to point to either being able to move, have a defence (thorns, chemicals) or to not feel pain.

Over to you ...

OK. The nerves we refer to here are damage sensors. They detect and report damage, and in humans, this results in the experience of pain, a feeling that encourages us to (try to) stop any further damage from occurring, and maybe also to fix the damage that has occurred. We already know that plants can detect damage, and 'report' it. What we don't know is how much, if at all, plants have any experience of pain. So we should be looking for that, I think. What we're trying to do here is to estimate the degree of aliveness of plants, to see whether we think they deserve the label "sentient" or "conscious", or something like it. So we need to consider whether plants have an experience of pain that is, in some way, comparable with the human experience. Don't we?

Back to you.

Pattern-chaser wrote: ↑December 21st, 2020, 1:27 pm

Greta wrote: ↑December 19th, 2020, 3:20 pmWhat plants can't do is move.

Plants do move, of course, but again, they do it much more slowly than we do. And they can't pick up their roots and walk, of course.

Glacier mice (moss balls) may provide an example of intelligent plant movement. They live on the ice and move by rolling. Scientists recently (2020) discovered that they move in herds across the ice.

(2020) Herds of moss balls mysteriously roam the North Pole together

The moss is not propelled by a slope, the wind or the sun, but the group moves in sync.

The glacier moss balls move together across the ice. Bartholomaus compares this to a school of fish or a flock of birds.

Bartholomaus said he hopes future generations will one day "sort out these great mysteries."

https://www.smithsonianmag.com/smart-ne ... 180975019/

Pattern-chaser wrote: ↑December 22nd, 2020, 9:37 am

Pattern-chaser wrote: ↑December 21st, 2020, 1:27 pm Plants do move, of course, but again, they do it much more slowly than we do. And they can't pick up their roots and walk, of course. But I think your focus on nervous systems is not quite right. We shouldn't be looking for an equivalent to a nervous system, but rather something equivalent to experiencing pain. As Mr Nagel says, we have no idea what it's like to be a bat, and rather less idea what it's like to be a plant. I don't think we should look for equivalents to human faculties, but for things that could function for plants like human skills do for us. Does that make sense?

Greta wrote: ↑December 21st, 2020, 7:49 pm Sure, you always make sense, just that I don't always agree with you. In lieu of overt responses in a vegetative state, we are to some extent forced to focus on structures rather than sensations, seeking equivalents to the structures that we know generate sensations in brained animals.

Maybe workshopping this would be helpful? To start, what use is pain and suffering? Why do very complex organisms (at least) hurt? But why? Why can't we just respond to stimuli without hurting? How could a sessile organism that experiences pain and suffering cope with the regular assaults that it can't deflect? The evolutionary pressures would seem to point to either being able to move, have a defence (thorns, chemicals) or to not feel pain.

Over to you ...

OK. 👍 The nerves we refer to here are damage sensors. They detect and report damage, and in humans, this results in the experience of pain, a feeling that encourages us to (try to) stop any further damage from occurring, and maybe also to fix the damage that has occurred. We already know that plants can detect damage, and 'report' it. What we don't know is how much, if at all, plants have any experience of pain. So we should be looking for that, I think. What we're trying to do here is to estimate the degree of aliveness of plants, to see whether we think they deserve the label "sentient" or "conscious", or something like it. So we need to consider whether plants have an experience of pain that is, in some way, comparable with the human experience. Don't we?

Back to you. 😉

Yes, pain is a damage report or, as regards mental pain, anticipation or awareness of damage. For example, about [cough] years ago, my sister and I waited at a bus stop, and she was playing a game with a young neighbour where they would jump on a small brick fence. My sister barked her shin on the wall and thought nothing of it. Then someone noticed blood on her long sock. She peeled it down to reveal her a gaping wound with her shin bone glistening with blood in the sun. At that point we all freaked out, even though she was not in pain. The wound needed 13 stitches.

Maybe we can clarify this by looking at our own pain. Why do complex animals feel pain, rather than respond automatically to damage? Wouldn't life be easier if we simply had neutral sensations to report incidents or damage rather than pain and suffering? Might such neutral, or relatively neutral, sensations exist in other organisms?



I don't think of it as aliveness, as such.

Greta wrote: ↑December 22nd, 2020, 10:11 pm Maybe we can clarify this by looking at our own pain. Why do complex animals feel pain, rather than respond automatically to damage? Wouldn't life be easier if we simply had neutral sensations to report incidents or damage rather than pain and suffering? Might such neutral, or relatively neutral, sensations exist in other organisms?

Well, they might, but isn't that what this discussion is about? It isn't really to do with whether plants can sense damage (they can), but whether, like humans, they have some mental experience that is roughly equivalent to our experience of pain (as opposed to simply being aware of damage)? If that is our aim, then "looking at our own pain" doesn't seem to help...? Surely we should be looking at the plants, not at ourselves?

Pattern-chaser wrote: ↑December 23rd, 2020, 10:12 am

Greta wrote: ↑December 22nd, 2020, 10:11 pm Maybe we can clarify this by looking at our own pain. Why do complex animals feel pain, rather than respond automatically to damage? Wouldn't life be easier if we simply had neutral sensations to report incidents or damage rather than pain and suffering? Might such neutral, or relatively neutral, sensations exist in other organisms?

Well, they might, but isn't that what this discussion is about? It isn't really to do with whether plants can sense damage (they can), but whether, like humans, they have some mental experience that is roughly equivalent to our experience of pain (as opposed to simply being aware of damage)? If that is our aim, then "looking at our own pain" doesn't seem to help...? Surely we should be looking at the plants, not at ourselves?

Nope, we need a baseline. If we don't know what's going on with ourselves, what do we measure plant sensitivity against?

The point is, what do people and dogs have that plants do not? And why? As I say, it makes no evolutionary sense for plants - or any sessile organism that is as completely exposed to attack as most plants - to feel pain. If they felt each injury, they would be in constant pain. Thus, the plant would be expending energy - and mental processes use more than any other - to traumatise itself. A plant that feels no pain would have two advantages - 1) less energy expenditure and 2) robustness in the face of injury - no trauma or emotions, they just get on with growing again.

That leads to the question: why does pain help humans and other animals survive? Pain, as far as researchers can tell, is selected in all brained animals. Pain - as with any sentience - is extremely expensive in the wild. (I expect you already know that our brain is responsible for about twenty percent of our total energy expenditure). So it must be a major benefit.

Brains allow organisms to be located advantageously in relation to dangers, resources and mates. Nature is competitive, and more awareness means being in a better position at a given moment than a predator or rival. I see no equivalence for plants.

Pain preserves the individual carrier of genes.

Neuropathic joints, often called Charcot joints, are caused by loss of sensation in the joint so that it is severely damaged and disrupted[1].

The Charcot foot is triggered by a combination of mechanical, vascular and biological factors which can lead to late diagnosis and incorrect treatment and eventually to destruction of the foot[2].

The damage and disruption becomes so gross that the diagnosis of a neuropathic joint is easily made as the destruction progresses, both on clinical examination and X-rays, because no one who had sensation would tolerate such destruction of the joint.

https://patient.info/doctor/neuropathic ... cot-joints

If plants moved around their habitat as a response to memory / learning they would need movable joints, muscles, and nervous systems to go with the joints and muscles.

Concerns about animals and their welfare is based on prevention of suffering.At this stage of knowledge we don't know any reason why plants would be sentient. Plants respond to violence which is why I prune my roses but I'd hate to think the plants were sentient.

Greta wrote: ↑December 23rd, 2020, 9:08 pm Nope, we need a baseline. If we don't know what's going on with ourselves, what do we measure plant sensitivity against?

You seek to measure plant aliveness using human aliveness as your yardstick? You are in more trouble than I thought!

Greta wrote: ↑December 23rd, 2020, 9:08 pm The point is, what do people and dogs have that plants do not?

And similarly, what do plants have that people and dogs do not? Perhaps it is here that we will find the thing that allows plants to be considered alongside other sentient, conscious, beings? Maybe....

Pattern-chaser wrote: ↑December 24th, 2020, 12:22 pm

Greta wrote: ↑December 23rd, 2020, 9:08 pm The point is, what do people and dogs have that plants do not?

And similarly, what do plants have that people and dogs do not? Perhaps it is here that we will find the thing that allows plants to be considered alongside other sentient, conscious, beings? Maybe....

The main thing plants do that we don't is to convert sunlight, water and CO2 into sugar and oxygen.

As Democritus noted, plants are akin to “[beings] with their heads in the ground”. By inference, we can assume that their genitalia are pushed up into the air. Human women, especially, delight in being gifted bunches of plant genitals and some will adorn both themselves and their surroundings in cheerful and colourful depictions of plant penises and vaginas. Strangely enough, we reject the idea of using such designs based on the bottoms of our close relatives:


Plants my have impressive (and ironic) capabilities but I cannot see any evolutionary advantage to plants feeling pain, as opposed to simply acting on stimuli directly, without the mediation of a mind that can suffer.

I have deliberately avoided comparing automatic behaviours of life with machines, because it's invalid and backward thinking. Machines are primitive echoes of wild nature, not the other way around. Since I see us all as parts of the Earth, we - including human society and its things - are all parts of nature, despite our affectations of independence. So microbes and plants do not resemble the operation of machines, rather machines can be thought of as both dumbed-down and domesticated biology and complexified geology.

But we can refer to automatic behaviours that are not mediated by a mind. Are there are plants behaviours that are not automatic, that can be influenced by mentality?

Belindi wrote: ↑December 24th, 2020, 5:48 am If plants moved around their habitat as a response to memory / learning they would need movable joints, muscles, and nervous systems to go with the joints and muscles.

The moss balls that I mentioned a few posts back, move in herds across the North Pole ice. They may have crawled out of the ocean.

There are people that keep moss balls as 'pets':

https://mossballpets.com/
https://ballsofmoss.com/

Waterlogged moss balls move up and down the fish tank. Remember, it’s a living organism and responds to environmental cues. We suggest you do your research to provide adequate care and also choose a place in your home before you actually make the purchase.

From this notice it can be deduced that the author believes that the moss ball is conscious and requires special care.

The movement of the moss ball across the ice is clearly intelligent:

"The whole colony of moss balls, this whole grouping, moves at about the same speeds and in the same directions," Bartholomaus tells NPR. "Those speeds and directions can change over the course of weeks."

He explains that herd of 30 moss mice that they observed first moved slowly southward before accelerating west, and then losing speed. Previous research using accelerometers had shown that the balls roll, and that the balls are green all over suggests that all sides get sunlight at some point. The new data show that the moss balls don’t move randomly—but the researchers couldn’t yet deduce what’s driving them.

The glacier moss balls didn’t follow any pattern that the researchers checked. The moss wasn’t rolling down a slope, getting pushed by the wind, or following the sun.

https://www.smithsonianmag.com/smart-ne ... 180975019/

There are small and large balls that manage to maintain the same speeds. This includes rolling up-hill en around rocks and obstacles.

Belindi wrote: ↑December 24th, 2020, 5:48 amConcerns about animals and their welfare is based on prevention of suffering.At this stage of knowledge we don't know any reason why plants would be sentient. Plants respond to violence which is why I prune my roses but I'd hate to think the plants were sentient.

Recent scientific discoveries show that plants have many neurochemicals that in animal brains are used for communication. It is simply not known yet why plants have such chemicals, as the discovery is fairly recent, but I do not believe that it is valid to assume that it is purposeless.

The root system of plants contains many neurotransmitters that are also present in the human brain, including dopamine, norepinephrine, serotonin and histamine. Recent discoveries indicate that the root system of plants can grow many billions of cells at the tips of the roots that function in the same way as brain neurons. For some plants, it would result in a number of neurons that rival those of the human brain.

Recently surprising similarities between plant cells and neurons
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2884105/

New research on plant intelligence may forever change how you think about plants
How plants sense and react is still somewhat unknown. Plants have a system for sending electrical signals and even produce neurotransmitters, like dopamine, serotonin and other chemicals the human brain uses to send signals.

"We don't know why they have them (neurochemicals), whether this was just conserved through evolution or if it performs some sort of information processing function. We don't know. There's a lot we don't know," Pollan says.
https://www.pri.org/stories/2014-01-09/ ... out-plants

Plants signal stress like animals do: with neurotransmitters
https://www.zmescience.com/science/biol ... r-0425634/

The mere plausibility of the consideration of plant sentience is evident from for example the emergence of a science field in general named Plant Neurobiology.

An outsiders perspective does not need to provide evidence for plant sentience. It would be sufficient to make a case for the plausibility of the foundation of a consideration. The emergence of a science field in general is a pretty strong foundation.

In 2005, Italian botany professor and plant neurobiology pioneer Stefano Mancuso and a group of international scientists established The Society for Plant Neurobiology and The Society of Plant Signaling and Behavior to study sophisticated behavior in plants—much to the jeers of many of their colleagues.

Not only do plants engage in neuron-like activity and movement, they make mathematical computations, see us and, like animals that act altruistically, show kindness toward their relatives. They are able to recognize themselves and communicate with animals and other plants via alluring airborne fragrances and a diverse repertoire of chemical compounds exuded through their roots.

As for movement, plants do move and they do so with intention. A plant flowers, orients its leaves, goes into sleep mode and even “plays” (for visual proof, see this TED talk).

In 2012 Daniel Chamovitz, director of the Manna Center for Plant Biosciences at Tel Aviv University and author of What a Plant Knows, reported that plants “see” us via photoreceptors that perceive different wavelengths of light. They are aware of when we come near them and whether we’re wearing a blue or red shirt.

In yet another study, in 2007 plant ecologist Susan Dudley of McMaster University in Ontario, Canada, worked with sea rockets—members of the mustard family native to beaches throughout North America, including the Great Lakes—to investigate whether plants can recognize their relatives. Dudley and a graduate student found there was less root competition when closely related “siblings” shared the same pot than when groups of strangers grew in a common container. This demonstrated that the sea rockets not only recognized but acted altruistically toward their relatives, a behavior known as “kin recognition.”

Other studies have indicated that plants are capable of self-recognition. In 1991, researchers Bruce Mahall of the University of California–Santa Barbara and Ragan Callaway, now at the University of Montana, found that the roots of white bursage plants, residents of the Mojave and Sonoran Deserts, inhibited the growth of other plants with which they came into direct physical contact but did not impede the growth of their own roots, meaning that they could distinguish “self” from “other.”

https://www.nathab.com/blog/research-sh ... cordingly/

TED: The roots of plant intelligence (Italian botany professor)
https://www.ted.com/talks/stefano_mancu ... telligence

Arjand, moss balls are no more pets than house plants but they are, at least, more pet-like than pet rocks.

Intelligence does not equal sentience. Thus, a chess computer can - without sentience - defeat a human chess grandmaster. A slime mould, without sentience, can navigate.

The question yet to be answered is what possible advantage would there be to plants to feel pain? The costs of sentience in nature are extreme, with a brain that comprises about 2% of a body's weight using about 20% of the total resources used by the body. So there needs to be a great reason to feel that pain.

In animals, pain motivates them to quick action. Great pain is traumatic for sentient beings. Yet a plant's life strategy is to always allow damage to happen before responding. In this instance, fine sensing without pain that triggers a rapid reflex response would seem most advantageous.

If reflex response needs no sentience. Thus, tree branches do not grow into each other, but they grow unabated into objects that are sensed as "other". This would require fine chemical sensing, like that of nanoscale bioelectric chemical sensors (which are not sentient).

Plants don't need to be sentient to be valued and treated with respect. They are, like all life, complex and fascinating. As a general ethical rule, if something is highly ordered - be it a human or other animal, a tree, a rock formation, a building or a functioning machine, etc - ideally we would need a compelling reason to disturb that order.

arjand wrote: ↑December 25th, 2020, 4:48 pm

Belindi wrote: ↑December 24th, 2020, 5:48 am If plants moved around their habitat as a response to memory / learning they would need movable joints, muscles, and nervous systems to go with the joints and muscles.

The moss balls that I mentioned a few posts back, move in herds across the North Pole ice. They may have crawled out of the ocean.

There are people that keep moss balls as 'pets':

https://mossballpets.com/
https://ballsofmoss.com/

Waterlogged moss balls move up and down the fish tank. Remember, it’s a living organism and responds to environmental cues. We suggest you do your research to provide adequate care and also choose a place in your home before you actually make the purchase.

From this notice it can be deduced that the author believes that the moss ball is conscious and requires special care.

The movement of the moss ball across the ice is clearly intelligent:

"The whole colony of moss balls, this whole grouping, moves at about the same speeds and in the same directions," Bartholomaus tells NPR. "Those speeds and directions can change over the course of weeks."

He explains that herd of 30 moss mice that they observed first moved slowly southward before accelerating west, and then losing speed. Previous research using accelerometers had shown that the balls roll, and that the balls are green all over suggests that all sides get sunlight at some point. The new data show that the moss balls don’t move randomly—but the researchers couldn’t yet deduce what’s driving them.

The glacier moss balls didn’t follow any pattern that the researchers checked. The moss wasn’t rolling down a slope, getting pushed by the wind, or following the sun.

https://www.smithsonianmag.com/smart-ne ... 180975019/

There are small and large balls that manage to maintain the same speeds. This includes rolling up-hill en around rocks and obstacles.


moss-balls.jpg

Belindi wrote: ↑December 24th, 2020, 5:48 amConcerns about animals and their welfare is based on prevention of suffering.At this stage of knowledge we don't know any reason why plants would be sentient. Plants respond to violence which is why I prune my roses but I'd hate to think the plants were sentient.

Recent scientific discoveries show that plants have many neurochemicals that in animal brains are used for communication. It is simply not known yet why plants have such chemicals, as the discovery is fairly recent, but I do not believe that it is valid to assume that it is purposeless.

The root system of plants contains many neurotransmitters that are also present in the human brain, including dopamine, norepinephrine, serotonin and histamine. Recent discoveries indicate that the root system of plants can grow many billions of cells at the tips of the roots that function in the same way as brain neurons. For some plants, it would result in a number of neurons that rival those of the human brain.

Recently surprising similarities between plant cells and neurons
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2884105/

New research on plant intelligence may forever change how you think about plants
How plants sense and react is still somewhat unknown. Plants have a system for sending electrical signals and even produce neurotransmitters, like dopamine, serotonin and other chemicals the human brain uses to send signals.

"We don't know why they have them (neurochemicals), whether this was just conserved through evolution or if it performs some sort of information processing function. We don't know. There's a lot we don't know," Pollan says.
https://www.pri.org/stories/2014-01-09/ ... out-plants

Plants signal stress like animals do: with neurotransmitters
https://www.zmescience.com/science/biol ... r-0425634/

The mere plausibility of the consideration of plant sentience is evident from for example the emergence of a science field in general named Plant Neurobiology.

An outsiders perspective does not need to provide evidence for plant sentience. It would be sufficient to make a case for the plausibility of the foundation of a consideration. The emergence of a science field in general is a pretty strong foundation.

In 2005, Italian botany professor and plant neurobiology pioneer Stefano Mancuso and a group of international scientists established The Society for Plant Neurobiology and The Society of Plant Signaling and Behavior to study sophisticated behavior in plants—much to the jeers of many of their colleagues.

Not only do plants engage in neuron-like activity and movement, they make mathematical computations, see us and, like animals that act altruistically, show kindness toward their relatives. They are able to recognize themselves and communicate with animals and other plants via alluring airborne fragrances and a diverse repertoire of chemical compounds exuded through their roots.

As for movement, plants do move and they do so with intention. A plant flowers, orients its leaves, goes into sleep mode and even “plays” (for visual proof, see this TED talk).

In 2012 Daniel Chamovitz, director of the Manna Center for Plant Biosciences at Tel Aviv University and author of What a Plant Knows, reported that plants “see” us via photoreceptors that perceive different wavelengths of light. They are aware of when we come near them and whether we’re wearing a blue or red shirt.

In yet another study, in 2007 plant ecologist Susan Dudley of McMaster University in Ontario, Canada, worked with sea rockets—members of the mustard family native to beaches throughout North America, including the Great Lakes—to investigate whether plants can recognize their relatives. Dudley and a graduate student found there was less root competition when closely related “siblings” shared the same pot than when groups of strangers grew in a common container. This demonstrated that the sea rockets not only recognized but acted altruistically toward their relatives, a behavior known as “kin recognition.”

Other studies have indicated that plants are capable of self-recognition. In 1991, researchers Bruce Mahall of the University of California–Santa Barbara and Ragan Callaway, now at the University of Montana, found that the roots of white bursage plants, residents of the Mojave and Sonoran Deserts, inhibited the growth of other plants with which they came into direct physical contact but did not impede the growth of their own roots, meaning that they could distinguish “self” from “other.”

https://www.nathab.com/blog/research-sh ... cordingly/

TED: The roots of plant intelligence (Italian botany professor)
https://www.ted.com/talks/stefano_mancu ... telligence

But animals' nervous systems include the ability to learn from experience by way of memory. If mossballs can remember then as well as feel pain and pleasure then I'd allocate rights to mossballs as conscious and sentient beings.

True, computers and such can remember and learn and adapt based on their memories, however computers and suchlike feel nothing. They are incapable of suffering and therefore need no welfare rights.

Greta wrote: ↑December 24th, 2020, 5:12 pm But we can refer to automatic behaviours that are not mediated by a mind. Are there are plants behaviours that are not automatic, that can be influenced by mentality?

Yep, that's what I am getting at.

Greta wrote: ↑December 25th, 2020, 5:58 pm The question yet to be answered is what possible advantage would there be to plants to feel pain?

Pain isn't a god example, I don't think. Our human reaction to damage is partly non-conscious. If I place my hand on a hotplate, it has already been snatched away before my conscious mind has registered the problem. My internal conscious processes are bypassed in this case, for obvious reasons. So pain, and my response to it, is not a great example of sentience. Perhaps social behaviour might offer greater insight?

Belindi wrote: ↑December 26th, 2020, 6:04 am But animals' nervous systems include the ability to learn from experience by way of memory. If mossballs can remember then as well as feel pain and pleasure then I'd allocate rights to mossballs as conscious and sentient beings.

True, computers and such can remember and learn and adapt based on their memories, however computers and suchlike feel nothing. They are incapable of suffering and therefore need no welfare rights.

A computer is a part of the human and is evidence of human consciousness and intelligence. Plants came into existence by themselves and could serve interests that lay outside of the scope of what humans can comprehend or foresee.

What is the purpose of a moss ball? Why would it roam the north pole in herds? It may be difficult for humans to see value in the existence of a moss ball. From the perspective of a moss ball however, there could be interests at play that span hundreds of thousands of years. Perhaps a moss ball plays a role in the creation of new animals. As it appears, owners of a moss ball pet feel emotionally attached and are awed by their intelligence / apparent responsiveness (i.e. potential for meaningful interaction that is comprehensible within the human realm).

With regard to the experience of pain and pleasure. Is (the ability for) memory of pain the criteria to assign meaning to pain?

As greta mentioned, it would first be important to establish what the concept pain means from the human perspective.

Greta wrote: ↑December 21st, 2020, 7:49 pmNope, we need a baseline. If we don't know what's going on with ourselves, what do we measure plant sensitivity against?

The point is, what do people and dogs have that plants do not? And why?

According to an emergent science field in general named plant neurobiology, plants are presumably 'slow animals'. The concept pain and happiness may express more slowly in plants.

Plants do 'move' and have their strategies to escape predation. An example is that some plants know how to attract the enemy of a predator. It is evidence that there is a memory of a bad event, and a memory of a "good" animal that can help the plant.

Plants Attract Enemy's Enemies To Survive
How do you overcome a strong enemy? Find an even stronger one of his. At least that's what some plants do when attacked by insects, according to a new study published in today's Science.
https://www.scientificamerican.com/arti ... nemys-ene/

Plants also seem to be crying in the face of stress, perhaps to ask for help from friendly animals.

Plants 'Scream' in the Face of Stress
https://www.livescience.com/plants-sque ... essed.html

If a plant does not know what is good and bad beyond what it could potentially know already, then, how would it know how to attract a certain animal to protect against another type of animal that is damaging to the plant?

It seems logical that plants would need to be capable of experiencing something similar to the concept pain in humans, but perhaps it would manifest differently.

An example for comparison:

If an alien creature from a fast rotating planet would visit earth and experiences time on a much faster pace, humans could be perceived by them similar to how humans perceive plants: meaningless, capable of creating complex structures but other than that, holding no value in relation to what matters to that fast moving alien, who, because of his speed, has full mastery and control over the human.

Do you believe that it would be valid to consider the human purposeless from the perspective of the alien who will never be able to see the intrinsic value of human concerns as in the time for the alien to live a full life, the human has been able to live a few days?