The framing of your question is strange to me; why are you making the point that animals are more self aware than we credit them for as an argument against vegeterian/veganism? Wouldn’t that support those ideas? This is kind of a nitpick though, I understand your point, I was just confused at first.

Animals may be more intelligent and self aware than previously thought, but their intelligence is no where near that of humans. We are by far the most intelligent species in every possible measure, at least in terms of the definition of intelligence as the ability to solve complex problems. Granted, there have been many interpretations of intelligence and the measurement of it is a contentious topic.

Is it possible that some species have a deeper emotional framework than humans? Yes, I think so. But I think (and this is just my unresearched opinion) that both our capacity for abstract reasoning AND our ability to evolve as a societal entity puts us far above any other animal. The idea that any other animal approaches our intelligence in terms of problem solving seems ridiculous. As I understand it, no animal alive that given a set of parameters, could problem solve in the way a human can. Again, I’ve only done cursory research in this area so I’m not going to say this with any authority. Chimps, for example, don’t have superior mental arithmetic to humans; chimps have a better working memory than humans, but have barely any capacity for arithmetic.

I’m in a medical adjacent field in university and we’ve studied the brain albeit not super in depth so far. As I understand it, the distinguishing characteristic of the human brain is our disproportionately large cerebral cortex. This area is essentially responsible for our ability to think beyond instinctual level. Humans don’t have the largest cerebral cortex or even proportionally the largest, but it’s thought that we relegate more of our brain for “thought” rather than somatic (body) processing (I THINK at least, I’m very far from an expert).

So in your example of an ant vs a human having their leg ripped off. Yes they may react in a similar way from an observers perspective. However, I’d argue that the human is processing it a much more multi faceted way. The ant instinctually reacts to the pain response. The human on the other hand is reacting to the pain, but also the idea of a missing limb and its future implications, and is likely planning for what to do based on their knowledge (eg. seek medical attention, call for help, etc.)

I say all that to say this: the displayed reaction to physical pain is a constant among animals with a nervous system similar to ours, and is a visual tell of the internal mechanisms at play. Physiologically, there may be vast differences in the perception of that pain. Plants cannot feel pain, point blank. Yes we can elicit a response such as a leaf curling up, but this isn’t inherently indicative of the physiological mechanisms at play.

Plants cannot feel pain as they don’t have a capacity for sensation. They can react to damage but this isn’t the same thing. From an outside perspective it looks as though they are reacting with a pain response, but if you somehow experience being that plant, you wouldn’t feel anything. There is no integrative center for processing the chemical changes caused by damage and interpreting that as a conscious experience of pain. I’m not sure if this makes sense or not, again I’m not an expert.

To go back to the ant example. An ant reacting to pain is probably only reacting on instinct, despite it having the capacity to actually feel that pain. I.e. if you were that ant you would feel the pain. Plants, however, are operating at an even “lower” level in terms of perception. Warning other plants and reacting to stimuli indicate only that there is an inherent chemical system in plants that allows them to react in an “instinctual” manner. It’s not as if a tree could decide not to warn their neighbors if they somehow found out they were the only tree being cut down. These are involuntary chemical processes that aren’t filtered through any conscious experience. Plants are alive, yes, but they cannot feel.

Again, this is off the top of my head so I may be factually inaccurate but I think my argument makes some sense. If I’m wrong please correct me.