You're conflating the definition with the correlated properties. > if the definition is to sense and respond to stimulus then the yes/no of "conscious" is alwa

You're conflating the definition with the correlated properties. > if the definition is to sense and respond to stimulus then the yes/no of "conscious" is always yes and therefore useless. This isn't the definition. This is a hypothetical cause. The cause might be anything; we don't know (yet?) what objective indicators there might be of subjective experience. Consider seeing. In order for a thing (be it robot, animal, or human) to see, it must possess some type of sensory organ and a method to interpret the signals from that organ. So, to test for the ability to see, we can look for those things. We can be pretty sure that fish can see, because they possess eyes, brains, and respond to visual stimuli. That doesn't mean the properties has_sight_organ and has_brain are seeing. In the same way that physical matter is all made of atoms (loosely; let's not be pedantic), we might find that all things possess consciousness. We might not. But in neither case is the term made useless. Sure, if we find that to be the case, then describing a thing as conscious or not becomes similar to describing an object as atomic. But then we're just moving goalposts.