In my interpretation, consciousness requires a soul. Lucid dreams are probably just our consciousness experiencing images generated inside our brain. An astral experience is when our soul enters the astral plane. Somewhere in between, our soul slips out into the astral..
The psychic community has not been able to supply hard cold evidence that such things exist. Other the other hand, there are too many goodies to abandon it. Given the mysterious circumstances surrounding the big bang and the birth of the universe, I just assume that an astral plane, and souls, were created by whatever caused the big bang. Even if it's hard to prove, the theory is still more likely than other "scientific" theories.