Throughout Past and Present, Daniel insists that Kera was a different person than Linea, and that she does not deserve to be punished for Linea's crimes. Was Daniel correct? Was Kera really a different personality within Linea's body? Was Kera really a sweet innocent, and Linea really a ruthless, wicked psychopath?
As far as I'm concerned, Linea and Kera are truly the same person. The Vorlox didn't change personalities; it simply removed memories along with years. Kera is what Linea was all those years ago, before she made deliberate choices that led her down a path that her younger self might have found as horrifying as Kera did.
I think it's important to recognize that Linea isn't eeeevil. She is a brilliant scientist with a very different set of morals that repulses us, but she does act within the guidelines she sets for herself, and with her own warped code of honor. And as far as I'm concerned, Kera shares those same personality traits; she just hasn't been confronted with the choices that led Linea down the path that brought her to Hadante.
Let's look at what we learn of Linea in Prisoners.
She took Sam under her wing without asking for anything in return. She saved Daniel's life, and not to gain credit with SG-1 - after all, she maintained that Daniel had won the fight himself. She restored Simian's vision for no other reason than because she could, without even the expectation of gratitude (she hardly looked surprised when the man fled without saying a word).
It is true that she might have been motivated by self-interest; newcomers represent a shifting of lines, and it's only pragmatic to keep the strangers alive long enough to determine if they can help her gain more power. But even if her actions were for her own benefit, saving Sam and Daniel, and healing Simian, is hardly the behavior of a psychopath.
Interestingly, she never actually lied to SG-1. She told Sam, point-blank, that she shouldn't be trusted: "Do not think that I am innocent." She stated that she was responsible for killing thousands, when her medicines accelerated a plague instead of curing it. (I'll get to her leaving out the detail of causing the plague herself in a bit.) The team chose to interpret her confession in the best possible way, but they were influenced by their need for her assistance to get out of Hadante.
Linea pursued knowledge obsessively. Even when Jack offered to take her with SG-1 when they escaped, she still wanted a guarantee that Sam would teach her how to use the Stargate system afterwards. During her brief period on Earth, Linea was interested in only one thing: gaining knowledge. She offered the bribe of the subatomic structure of her activators to get Sam to show her how to use the computer, which fits well with the philosophy she quoted to Sam on Hadante: "I've long believed that the best way to get knowledge is to give it."
Once she had enough information to figure things out on her own, she zapped Sam and the others into unconsciousness, effortlessly hacked the SGC's database and systems, and managed a flawless escape. Note that while she could have easily blown the base to cover her tracks, she had the self-destruct abort once she was safe: "All debts are finally paid." It's clear she has no trouble with killing, but she doesn't kill without reason.
Now, a few thoughts on "The Destroyer of Worlds." Here is what Linea asserted: "There was an experiment with tragic consequences. People died.... Thousands. It began with a terrible plague among the people who sent you here. Time was short. I offered my knowledge. Instead of inhibiting the disease's progress, my medicine accelerated its effects."
And here is Simian's accusation: "The Destroyer of Worlds. She created a sickness. The one you call Linea, she - the Destroyer.... Not help. She started it. Our island states were at war. She created a sickness - one she couldn't get herself. A terrible sickness. Half our people died. She came - promised to save the rest. By then it had spread, island to island. By the time they caught her, she had destroyed half a world."
It seems to me that Simian is saying exactly what Linea did, with a single exception: that the "experiment with tragic consequences" was Linea's to begin with, manufactured deliberately because of the war between the island states.
So the question is, who was telling the truth? I do think that Simian was right in one respect: Linea probably did perform some kind of experiment that unleashed the plague. She tried to cure the victims, failed, and was sentenced to Hadante. As I mentioned before, Linea didn't actually lie about this. "There was an experiment" doesn't deny the possibility that the experiment was hers.
But that doesn't mean that Linea's experiment-gone-wrong was a deliberate act of war, as Simian claims. It's quite possible that Simian is repeating the propaganda that his government has spread - that the plague was not only accelerated by the woman who claimed to want to help, but that she viciously caused it in the first place. Even the name "Destroyer of Worlds" sounds like something coined by the local equivalent of a scandal sheet.
(This isn't an attempt to exonerate Linea of her crimes, but to clarify that she really can't be realistically condemned as an crazed, evil mastermind.)
So where does that leave us? With a woman who is brilliant, but doesn't shy from conducting experiments on human beings; with a person who tries to fix mistakes, not out of compassion (probably) but either to see if she can or to satisfy her own personal code of honor. It leaves us with a woman who might lie by omission, but openly states her goals and desires; and with a woman who won't let anyone stand in her way, but avoids killing if it isn't necessary.
Now, getting back to Past and Present, how much of that characterization is contradicted by Kera's behavior?
As far as I can tell, not very much.
Kera is willingly helping others - just as Linea did with Simian. She is calmly in a position of power - just as Linea was. As Linea observed to Sam in Hadante, "There are many forms of power, my dear. Some more subtle than others." Kera is eager to pursue knowledge, swiping the antidote because she can't bear not to know. (Sound familiar?) She is unfazed by fallout in the form of human beings - consider how she barely blinked when Orner nearly died, and wanted to get right back to fine-tuning the formula.
All these character traits seem very much of a piece with Linea. The only difference between Kera's behavior and Linea's is that they do not share the same past.
Then there's Kera-Linea's confrontation with Daniel, when she knows who she was. Without having made the conscious choices that led Linea to act as she did, Kera is horrified enough to attempt suicide. She waits to see if she'll still be needed, acknowledges that "all debts have now been paid," and prepares to die by smashing the two vials that we've been told can form a poisonous gas.
When Daniel tries to stop her, she tells him, "There's a part of me that cares for you, Daniel - more than I've cared for anyone I've ever known. But there is this other part of me that would gladly watch you die! ...There are two people inside of me, and one of them is a monster. In time, she will win.... I'm not her!"
Who is speaking here? Kera, overwhelmed by Linea's memories but not her personality? Kera, speaking of herself and Linea as two separate entities? Linea, remembering who Kera was? Linea herself? A hybrid of both? By the end, that is Linea speaking, furiously denying that she's Kera. When did Linea "take over"? It's hard to tell, and perhaps that difficulty only highlights what I'm saying: Kera and Linea really are very much the same.
We don't know what events or choices led Linea to create the experiment that unleashed a plague; for all we know, it might have been authorized, just as the Vorlix was unleashed while she was openly working with two of the Vyan elders. Kera is spared the history and life decisions that carried Linea down her particular path, but there is nothing in Kera's characterization that would suggest that she could choose any differently, were she faced with the same circumstances.
My own conclusion is this: Kera is not the innocent to Linea's monster. They are both the same person, but without the same life experiences, and I think that Kera has the dangerous potential to become Linea all over again. Perhaps her sweet personality really proves that nurture triumphs over nature, but I'm more inclined to suggest that the nature hasn't changed, and as kindly as she seems at the moment, the Vyans are going to be in very deep trouble if Kera ever gets a little too absorbed in chemical experimentation.
In any case, I welcome dissension and discussion. :)
And thanks to sg_betty for the e-mail conversation that inspired this meta in the first place!