You’re conflating very different processes here. While there is the hard problem of consciousness and we can’t falsify ideas like panpsychism consider a few things.
If you amputate my hand and press on it it will emit nervous signals. Does anyone feel pain? If you destroy most of my brain but keep me alive, then stab me almost all the nervous activity and hormones etc associated with injury will happen. Is there any reason to believe there is any pain felt?
I would say no in both cases, pain is not emitting nervous impulses, or something that precedes releasing endorphins and inflammatory factors etc. Pain cannot even necessarily be reliably correlated with stress markers like heart rate, and in the case of phantom limb syndrome pain can even be associated with a complete lack of signals.
There are good evolutionary reasons to exhange information and resources, even unwittingly. Apparently some bacteria in my tummy are in conversation with my body constantly but I’m not at all aware or actively participating in that. Maintaing pain only really seems to offer advantage if you can do something about it, while it’s possible for things to exist accidentally it’s not like grass can move to places without mowers or trees shade themselves. In all animals with nervous systems the nervous systems are the vastly most expensive thing to keep alive. In fact there are a few creatures who when entering an immobile stage of life rapidly digest their own (a good explaination for both tenure and retirees!).
Plants don’t have rapid long distance communication in their bodies, they don’t have centralised organs, they don’t even have anything approaching the levels of activity we associate with the simplest nervous systems.
It’s probably best to think of grass “screaming” as skin cells “screaming” for resources to make more melanin when exposed to UV. Or lymph nodes “screaming” when releasing hormones to heal a wound and stuff. This is all vastly below the level of consciousness.
Or whatever, embrace panpsychism, like the invisible dragon in my garage nobody can prove it false /shrug. Animals eat plants though and thermo law 2 is a thing so even panpsychics minimise suffering by being plant based.
But what I am arguing is that is an anthropocentric view of what constitutes pain and suffering. We cannot assume either is not possible without a nervous system. It’s worth at least looking into the concept even though we don’t know that there would be a mechanism simply based on what we know about plants so far. I myself would put myself on the no side when it comes to whether or not plants feel pain, but I couldn’t say that it was a 100% definite no by any means and I think we may feel very differently about what it means to be a plant and what plants are capable of in 20 years.
You’ve got to operate on evidence, there’s an infinite number of things you can’t falsify and you have no criteria for choosing which to believe or not.
In other animals we observe things consistent with pain such as long term behaviour modification in the absence of a persistent hormone. Things like avoiding places they were injured, becoming more cautious or less curious, even changes that destroy them like starving themselves to death.
Anyone that says “only humans feel pain” is a chauvinist ignoring stuff like rats giving up the will to live.
But trees or mosses or whatever do none of this. A tree will keep trying to grow towards a fence that damages branches in a storm, a tree never starves itself to death making thicker bark after teens carve lovehearts into it, a tree doesn’t stop reproducing after 3 droughts kill all its children and so on. Leaves might change colour in response to periods of high or low sunlight but these changes are like tanning, they don’t modify anything about how the tree trees.
We can’t know is true, but we also can’t know I don’t have an invisible dragon in my garage. you should definitely not live your life thinking I have an invisible dragon in my garage. Why? you don’t have any evidence to suspect it’s real that is distinguishable from a random lie. We have no evidence of behaviour in trees indistinguishable from chemical signals we know are below the level of consciousness in ourselves.
But trees or mosses or whatever do none of this. A tree will keep trying to grow towards a fence that damages branches in a storm, a tree never starves itself to death making thicker bark after teens carve lovehearts into it, a tree doesn’t stop reproducing after 3 droughts kill all its children and so on. Leaves might change colour in response to periods of high or low sunlight but these changes are like tanning, they don’t modify anything about how the tree trees.
I don’t know why any of this means that our nebulous definitions of ‘pain’ and ‘suffering’ cannot apply to plants.
If I stub my toe, it doesn’t modify anything about how I human. But it hurts.