As far as I remember, from around the forth book in Wheel of Time, Rand begins to hear and have conversations with a voice in his head that he believes to be that of Lews Therin Telamon -- the Dragon.
This seems to stop in The Gathering Storm after he has a bit of a tantrum, and had stopped in an earlier novel for a period when again (if I recall correctly) "Lews Therin" was scared by Cadsuane.
So was he actually talking with himself from a past life, or is it the taint?
The Voice is meant to be a source of mystery and Jordan never reveals a definitive answer on this subject for us readers.
QUESTION
There have been rumors that you have said that Mr. Jordan did not have anything in his notes about the voice of Lews Therin, whether it was a construct or not. That or that you had sai—[cut off]
BRANDON SANDERSON
I would like to clarify this, thanks for asking. I will NOT say that it was not in the notes. However, Mr. Jordan did NOT want to reveal this information, and therefore I shall not ever either. Mr. Jordan did not want to reveal it.
HARRIET MCDOUGAL RIGNEY
What Brandon said.
Further we have this interview here Brandon states that the Taint has something to do with it, it's just not the full story. As Sanderson references Sermihage states that hearing voices was a sign of incurable madness from the taint.
MATT HATCH
Was the taint influential in the creation/development/existence of the voice of Lews Therin in Rand's head?
BRANDON SANDERSON
Brandon answered that the taint was influential, but not the only factor. He referenced Semirhage, that of course we can't believe the Forsaken always, but yes, that the taint was an influence in the the voice. That we have to accept that in fact, in a way, Rand is going insane (as in as the books progress).
And finally a quote from Robert Jordan himself.
SCOTT CARLSON
The first was: "Lately Lews Therin has been in Rand's head increasingly, and increasingly, Lews Therin has been bemoaning that he's got voices in his head. Is Lews Therin merely a disembodied voice in Rand's head in Rand's time, or is there some kind of time-spanning link between them, and Rand is concurrently a disembodied voice in Lews Therin's head in the Age of Legends?"
ROBERT JORDAN
RJ replied that it is the former; that Lews Therin is a disembodied voice that refuses to believe he is a disembodied voice.
This quote shows that Lews Therin's voice is purely inside his head, whether real or not, and not tied to anything outside his head.
Finally,
“He’s insane,” she said coolly. Standing there stiff as a statue, Min’s knife hilt still sticking out beside her collarbone and the front of her black dress glistening with blood, she might have been a queen on her throne. “Graendal could explain it better than I. Madness was her specialty. I will try, however. You know of people who hear voices in their heads? Sometimes, very rarely, the voices they hear are the voices of past lives. Lanfear claimed he knew things from our own Age, things only Lews Therin Telamon could know. Clearly, he is hearing Lews Therin’s voice. It makes no difference that his voice is real, however. In fact, that makes his situation worse. Even Graendal usually failed to achieve reintegration with someone who heard a real voice. I understand the descent into terminal madness can be . . . abrupt.” - Semirhage Knife of Dreams pg 612
This quote from Semirhage basically confirms (if she can be trusted) that Rand's diagnosis is due to madness, as she herself was an authority figure in the AoL in regards to things like this.
Key Point Rand does actually have access to Lews Therin's memories, so while we speculate on the taint causing the disembodied voice, the majority of the stuff Lews tells him is true.
As we see later in the book, Rand gains complete integration between Lews Therin's memories and his own during his "Ascension"
I believe this was answered in the books.
The voice in Rand's head is a manifestation of madness caused by The Taint, as Cadsuane and others have stated in the series, but also Rand's way of dealing with being the Dragon and what he's destined to be and do.
From The Gathering Storm, Midnight Release signing
Was the taint influential in the creation/development/existence of the voice of Lews Therin in Rand's head?
BRANDON SANDERSON
Brandon answered that the taint was influential, but not the only factor. He referenced Semirhage, that of course we can't believe the Forsaken always, but yes, that the taint was an influence in the the voice. That we have to accept that in fact, in a way, Rand is going insane (as in as the books progress).
So what are the other Factors?
From the Robert Jordan, New York Barnes and Noble signing on January 7, 2003:
Q:The question is, with Rand and LTT, do they have 1 soul or 2 souls in the body?
A: They have 1 soul with 2 personalities. The reincarnation of souls does not mean reincarnation of personalities. The personality develops with each reincarnation of the soul. This is the cosmology that I [cobbled] together
We know that Rand is the personality of the Dragon we follow in the series. Lews being there as a distinct true personality doesn't fit with the information above.
However Rand is going through two things -
1. Sharing the soul of the Dragon with another personality
2. Making himself hard, supressing emotion as this is how he feels he needs to be.
The only way that he can accept also being the previous Dragon is to compartmentalise "Lews" away.
We can see this here and in other occurrences:
In his room at The Counsel's Head, Rand sat on the bed with his legs folded and his back against the wall, playing the silver-mounted flute Thom Merrilin had given him so long ago. ... The tune was called 'Lament for the Long Night', and he had never heard it before in his life. Lews Therin had, though. It was like the skill at drawing. Rand thought that should frighten him, or make him angry, but he simply sat and played, while Lews Therin wept.
Winters Heart, Chapter 25, Bonds
When Rand has his epiphany -
Why do we live again? Lews Therin asked, suddenly. His voice was crisp and distinct.
Yes, Rand said, pleading. Tell me. Why?
Maybe… Lews Therin said, shockingly lucid, not a hint of madness to him. He spoke softly, reverently. Why? Could it be… Maybe it’s so that we can have a second chance.
...
Within that moment, suddenly something amazing occurred to him. If I live again, then she might as well!
The Gathering Storm, Chapter 50 - Veins of Gold
The she is Ilyena, who Lews killed in his madness and the thought is Rand's, implying that he is finally accepting the portion of him that is/was Lews.
The voice stops when Rand accepts his destiny (emphasis mine).
For they were not two men, and never had been.
He regarded the world beneath him. The clouds above had finally broken, if only just above him. The gloom dispersed, allowing him to see the sun hanging just above.
Rand looked up at it. Then he smiled. Finally, he let out a deep-throated laugh, true and pure.
It had been far too long.
The Gathering Storm, Chapter 50 - Veins of Gold
Himarm's answer makes it clear that RJ intended this to remain a mystery. However, here's some canon evidence - interpret it how you will.
"Some men who can channel begin to hear voices." [Cadsuane] spoke almost absently, frowning at the flattened sphere of silver and gold. "It is a part of the madness. Voices conversing with them, telling them what to do. " The teapot drifted gently to the floor by her feet. "Have you heard any?"
Startlingly, Dashiva gave a raucous laugh, shoulders shaking. Narishma wet his lips; he might not have been afraid of the woman before, but now he watched her as closely as a scorpion.
Personally I've always taken this to mean that many male channellers hear voices as part of their madness, but Lews Therin's voice is an exception. Not all male channellers are the So-and-So Reborn, as Rand is.
It could also be interpreted to mean Rand is just an example of a man who channels, starts to go mad, and hears voices in his head. My argument against this is that Rand also picks up knowledge from Lews Therin - knowledge from the Age of Legends, which is corroborated in Forsaken-PoV chapters. How would he have gained that if he's just imagining the voice in his head?
Disclaimer: obviously I (Rand) only know what I myself have experienced, and can only judge from that. If Narishma would like to tell me about his own experiences in the comments, I'd be most grateful.
Yes, Rand is going crazy and the voice in his head is a part of this. The fact that it's Lews Therin apparently has nothing to do with this, as Cadsuane, in book 7, comments on this being connected to the taint. In book 11 Semirhage comments on this being seen on the AoL and says that if the 2 personalities cannot integrate the person goes insane.
