I have always believed that consciousness was not something that has likely just evolved on earth either. Intelligent life with consciousness has been seen as a possible "fluke" on earth, that it is entirely a rare event "out there". Why should it be any more rare an evolutionary advantage than any other trait--like ears, eyes, voice boxes etc. I am with Simon Conway Morris on this topic; biology works with the other sciences. If intelligence is rare, it will only be because it might very well have a built-in mechanism for "self destruct" when it becomes not an advantage to the species that exhibits it or to the other species that must endure the results--case in point, our earth.
By the way, a sideline, I know some people who cannot tell the difference between what they see in the mirror and what they are in reality. The power of the mind!