I'm not sure it's that clear. What about a person who is on drugs to the point they clearly don't know what reality is happening around them, but they are able to speak and move and such? I'm not sure I'd call that conscious, but by most definitions it is.

Indeed, doing a first aid course we were pointed out that sleeping is different from being unconscious. You can wake someone from sleep pretty quickly. You can't bring an unconscious person back in the same way.