Let's distinguish between superficial and fundamental ignorance. If you flip a coin, you may not know which way it came up until you look. This typifies what I will call superficial ignorance. The mechanics of a flat disk of metal, sent spinning in a certain way, is not an especially mysterious subject. Your ignorance of whether the coin shows head or tails does not imply ignorance of the essence of what just happened.
Fundamental ignorance is where you really don't know what's going on. The sun goes up and down in the sky and you don't know why, for a third of each day you're in some other reality where you don't remember the usual one, and so on. The situation with respect to consciousness is in this category.
It could be argued that you should care about any instance of fundamental ignorance, because its implications are unknown in a way that the implications of superficial ignorance are not. Who knows what further wonderful, terrible, or important facts it obscures? Then again, it could be argued that there's fundamental ignorance beneath every instance of superficial ignorance. Consider the spinning coin: we have a physical mechanics that can describe its motion: but why does that mechanics work?
Conversely, in the case of consciousness, there's an argument for complacency: I may not understand why brains are conscious, but human beings pretty consistently act in the ways that I tentatively regard as indicative of consciousness, and (I could say) in my dealing with them, it's how they behave which matters.
There are a few further reasons why someone may end up caring whether other people/beings are truly conscious or not. One is morality. I may consider it important to know (if only I could know), whether they really are happy or suffering, or whether they are just automata pantomiming the behaviors of happiness and suffering. Another is intellectual curiosity. Perhaps you just decide that you want to know, not because of the argument from the unknown significance of fundamental ignorance, but on a whim, or because of the cool satisfaction of grasping something abstract.
But perhaps the number-one reason that someone from this community should want to know, is that many people here anticipate that they personally will undergo transformations such as mind uploading. If you at least value your own consciousness, and not just your behaviors, then you have an interest in understanding whether a given transformation preserves consciousness or not.
I think that you are unintentionally conflating two very different questions:
1). What is the mechanism that causes us to perceive certain entities, including humans, as possessing consciousness ?
2). Let's assume that there's a hidden factor, called "consciousness", that is sufficient but not necessary to cause us to perceive humans as being conscious. How can we test for the presence or absence of this factor ?
Answering (2) may help you answer (1), but (2) is unanswerable if the assumption you are making in it is wrong.
I personally see no reaso...
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A list of some posts that are pretty awesome
I recommend the major sequences to everybody, but I realize how daunting they look at first. So for purposes of immediate gratification, the following posts are particularly interesting/illuminating/provocative and don't require any previous reading:
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