Read any book or website on animal rights and there’s a high chance you’ll come across the above quote, from philosopher Jeremy Bentham. Animal rights activists believe that animals deserve moral consideration from humans, not because of their intelligence, usefulness to humans, or importance to the ecosystem, but because they are conscious beings who care how they are treated
However, there is a difference between the sensation of pain and the perception of suffering. Sensation is a purely mechanical process. Machines can be programmed to “feel” “pain,” that is to sense harmful stimuli and take action to escape it. But if their defenses fail, there’s no reason (yet, at least) to think they experience agony or dread over being harmed.
We cannot say, then, that just because something feels pain it necessarily suffers. If animals, aliens, or AIs are not conscious, they cannot suffer, and their pain doesn’t matter in any moral sense. But if they do suffer, then their pain matters a great deal, at least from their own perspective. If we place ethical value on others’ experiences, then their pain should matter to us as well. This is why consciousness is so important.