Plants don't have a central nervous system or a brain. What science generally understands under pain and suffering plants simply don't have.
Quite a number actually do have nervous systems [0], using neurotransmitters that have actually been found in mammals. They respond to wounding, both with efforts to repair it, and with chemical deterrents to the cause.
Now, that isn't to say that they necessarily have pain and suffering, but it wouldn't be surprising to learn that some plants possess that capability.
Jellyfish have a nervous system but not a CNS.
I have no idea where the ethical line ought to be here, but if plants have meaningful capacity to suffer then it’s also likely that PETA should be campaigning to limit the mistreatment of even the tiny AI we make while doing MOOCs on the basics of machine learning.
It went on to argue with me about data points it thought were outliers that should be removed.
So? does that automatically imply that it does not feel pain?
>What science generally understands under pain and suffering plants simply don't have.
Listen, I don't buy the science say this and science say that kind of arguments. ANY living being ( assuming we can settle for what can be called 'alive') will have a mechanism for self preservation, pain is one of them. The onus is on 'science' or people to prove otherwise.
Neither of these are applicable to plants, so there doesn't seem to be any evolutionary reason to evolve pain receptors.
(Maybe not by insects though.)
The fact that fruits need to be eaten to perpetuate the species is not linked to the existence of humans.
Birds, mammals, many species disseminate seeds.
No central nervous system does imply no mind to feel pain.
If you were to scoop my brain out of my body and keep my lower body alive below the neck the nervous system would not feel pain as there is no mind to feel it.
Science can't prove the world is not the dream of a giant turtle- so technically I can't "know" anything- so asking "how can you know that?" Is kind of a boring line of questioning. It has no answer other than "Well I guess technically I can't know that, or anything," But that doesn't mean turtle dreams are going to get equal weight with our empirical models of the world.
Or there could be none besides those with a CNS. Science may have a long way to go on understanding minds, but speculation on other sorts of minds entirely is still within the realm of science fiction. So, if you're going to assert something like a conscious experience by plants then you should understand that you are taking it as an article of faith.
A cornerstone of science is empirical observation, and we can all observe our own consciousness to some degree. It's hardly perfect or even nearly complete, but it's something.
You can play semantics with the word "pain" all you want, but the biological differences between what we call pain as experienced by humans and the stimuli response from plants are sufficiently different to surpass a difference of degree and make it a difference of kind. You need a word besides "pain", or the onus is on you to demonstrate the appropriateness of that term when you are using it so far outside its normal context.