The starting point is the consciousness we already know. That is ourselves, which most people then extend to others, however it's not hard to then extended to at the very least mammals. I then extend this to most animals (whether it's 100% is irrelevant for this point). That extension from my consciousness to all animals is a small logical leap based on biology and our shared tree of life... however it doesn't mean other consciousnesses are not possible. It's more so that they would require a lot more evidence and a proper theory of C. in order to validate. Without that theory we can only point at similar C., of which LLMs are not displaying. They are showing a different kind of "cognition" if we can even call it that (I do think it's debatable).
So it's more a hueristic. We know one kind of C., therefore that's what we should look for. Statistically it's probable that there are many more ways to show similarities with conscious behavior which are NOT conscious, then it is for a divergent behavior to happen to be conscious. In other words, there are more ways to fake similar behavior than to land on an actual conscious behavior that is somehow much different than what we know.
So it's more a hueristic. We know one kind of C., therefore that's what we should look for. Statistically it's probable that there are many more ways to show similarities with conscious behavior which are NOT conscious, then it is for a divergent behavior to happen to be conscious. In other words, there are more ways to fake similar behavior than to land on an actual conscious behavior that is somehow much different than what we know.