Isn't it plausible that a clever species such as our own might need less pain, precisely because we are capable of intelligently working out what is good for us, and what damaging events we should avoid? Isn't it plausible that an unintelligent species might need a massive wallop of pain, to drive home a lesson that we can learn with less powerful inducement?
I don't think it's plausible at all. The smarter a species is, the more scope it has to go wrong outside of basic actions, the more urges it has unconnected to basic eating and mating. Even a smart species can't directly calculate the fitness of every action. (Heck, I couldn't calculate the fitness of eating right versus eating wrong.) At best, I'd say intelligence has an indeterminate relationship, and if I were allowed to appeal to humans for evidence, I'd point out all sorts of utility-raising and fitness-lowering behaviors like condoms or memes where the intelligence has rather backfired on the genes.
Link: boingboing.net/2011/06/30/richard-dawkins-on-v.html
Imagine a being so vast and powerful that its theory of mind of other entities would itself be a sentient entity. If this entity came across human beings, it might model those people at a level of resolution that every imagination it has of them would itself be conscious.
Just like we do not grant rights to our thoughts, or the bacteria that make up a big part of our body, such an entity might be unable to grant existential rights to its thought processes. Even if they are of an extent that when coming across a human being the mere perception of it would incorporate a human-level simulation.
But even for us humans it might not be possible to account for every being in our ethical conduct. It might not work to grant everything the rights that it does deserve. Nevertheless, the answer can not be to abandon morality altogether. If only for the reason that human nature won't permit this. It is part of our preferences to be compassionate.
— Albert Einstein
How do we solve this dilemma? Right now it's relatively easy to handle. There are humans and then there is everything else. But even today — without uplifted animals, artificial intelligence, human-level simulations, cyborgs, chimeras and posthuman beings — it is increasingly hard to draw the line. For that science is advancing rapidly, allowing us to keep alive people with severe brain injury or save a premature fetus whose mother is already dead. Then there are the mentally disabled and other humans who are not neurotypical. We are also increasingly becoming aware that many non-human beings on this planet are far more intelligent and cognizant than expected.
And remember, as will be the case in future, it has already been the case in our not too distant past. There was a time when three different human species lived at the same time on the same planet. Three intelligent species of the homo genus, yet very different. Only 22,000 years ago we, H. sapiens, have been sharing this oasis of life with Homo floresiensis and Homo neanderthalensis.
How would we handle such a situation at the present-day? At a time when we still haven't learnt to live together in peace. At a time when we are still killing even our own genus. Most of us are not even ready to become vegetarian in the face of global warming, although livestock farming amounts to 18% of the planet’s greenhouse gas emissions.
So where do we draw the line?