It fits with everyday uses of the word "conscious". Let's say someone is lying motionless on the ground. You then say they've "lost consciousness". Later, th

It fits with everyday uses of the word "conscious". Let's say someone is lying motionless on the ground. You then say they've "lost consciousness". Later, they wake up and object that they were not unconscious. "I could hear everything you said. I was paralysed, but conscious the whole time." Being able to relate their experience is what proves that they were conscious. Someone will say that they "made a conscious decision". Same thing. They can relate the thought process behind the decision. Someone will say: "I got lost on the way to the airport. I must have unconsciously wanted to stay home." In this case they tell you that they made a decision, but they cannot relate the thought process behind the decision, and they don't believe that at any point they could have. It is a decision not available to introspection, therefore "unconscious". > the question under investigation What investigation? Which observation is in need of explanation? All I have is the introspective observation of myself thinking, and reports from others making similar introspective observations. If you are going to say that "consciousness" needs explanation, then your question is ill-formed, because your question contains a word that has no definition and no agreed upon meaning.