What Exactly Are Hearts in Kingdom Hearts?
As much as what any fictitious scientists do, it may be difficult for us to grasp what exactly Ansem and his apprentices were studying both before and after Xehanort joined them. The truth may be found in the Ansem Reports of the first two games, but they are vague and highly contradictory due to the retcon. All we know for sure is that, like Master Xehanort, they were concerned with the darkness in people's hearts and were willing to take drastic measures to find answers. However, what does constitute a heart, and why is it so important for them to discover?
The real Ansem's reports mentioned psychological analyses, which Even in particular had been all about. However, Vexen was the one in charge of the Replica Project, which also would have required extensive knowledge of biology on his part as well (not to mention medical knowledge for taking care of Braig's injuries and Xehanort after he'd collapsed). Up until the creation of Heartless and Nobodies in their experiments, their work was most likely theoretical rather than applied. Master Xehanort had been able to create a separate person from Ven using his darkness, causing Ven to almost die with half a heart. These are most likely not literal, beating hearts in this sense; we cannot even be sure that Nobodies or Heartless have circulatory systems since blood is censored on normal people to begin with. A heart removed by a Keyblade or other methods is either spherical or heart-shaped, so this would indicate souls or emotional hearts as the basis of study. The question later became whether or not Nobodies still had hearts; the answer was also confusing.
When a person's heart is removed, their being splits in two, the darkness becoming the Heartless (which keeps the heart) and the otherwise empty shell becoming a Nobody (which keeps the consciousness). When they are destroyed, they fade into darkness and reconstitute the person where they fell if they managed to regain or regrow their hearts. Hearts can be regrown through experience, though more needs to be revealed on the matter since the characters spent most of the games adamantly refusing to believe that Nobodies had hearts or would ever have them again. Nobodies feel pain and get tired like normal people, and they still have brains containing memories from their lives before their hearts were removed. Memories of these emotions as well as the emotions themselves are regulated by the limbic system (which includes the hippocampus and amygdala), so there's no reason for them to believe they don't have feelings if they know their biology, which they should. However, Xemnas tells them that their emotions are not genuine without their hearts and that they are just behaving according to their memories. It's not entirely clear what happens after the initial shock of losing their hearts and becoming Nobodies; do all their memories come back at once and put them into a coma for a few days, or do the memories come back a little at a time?
Most Nobodies keep the personalities they had when they were people, although they may have undergone changes depending on their reaction to what had happened to them. Xigbar and Vexen are the most expressive out of the first six, being the oldest and set in their ways; their personalities have perhaps changed the least, not as daunted by their current state. Xaldin and Lexaeus are more stoic and in control of their emotions as the obedient guards but perhaps not as happy as they once were. Zexion is a kid, so while he is usually able to convince himself that he doesn't have emotions, he is still prone to the occasional outburst when pushed to his limits. Because emotional responses are an integral part of being alive, there is a running gag of people calling them on using emotionally-charged phrases as if they shouldn't apply to them (they do this to each other too, but if this were even more like Blade Runner, it would border on fantastic racism and already does). The brain learns, so based on their memories they should be able to have the same emotional responses they used to when comparing new memories as Nobodies to old memories as people. There has to be more to it than if they just grew them back (and not in test tubes either as we are still not talking about literal hearts).
Regrowing hearts requires the Nobodies to care about someone or something. This defies Xemnas' will, and he wouldn't be able to control them to use as vessels. Having no emotions and not being allowed to care about anything...If that's not the plan of a Care Bears villain, I don't know what is. Master Xehanort wants to forge the X-Blade and claims to want to bring light and darkness into balance, but that isn't for him to decide. People need to make their own choices and find the balance within themselves. Being the villain, he wants to force everything, especially his will, onto others while railing against those he claims force their views on him (namely Eraqus and his pro-light/anti-dark agenda). As we see in 2.5, Braig is the first one awake, but he is already "half Xehanort" and is talking to young Xehanort while everyone else is still unconscious; while there is no doubt in my mind he still cares about everyone, the reason he is up is because he's been "half Xehanort" for a long time (as Isa is too but is still unconscious). Next is Lea, who regrew his heart due to his friendship with Roxas, then Aeleus and Ienzo, who are close friends too. Hopefully Dilan and Even will soon follow.
In conclusion, we may never be privy to all the details of this fictional research. Ansem did give Riku his notes in Dream Drop Distance, so we may learn more in III. These will be the retcon reports since the ones from I and II are contradictory in regards to the timeline and who wrote what (and who knew and did what and when). As they are safely in Riku's possession, they would most likely be presented in the form of the Secret Reports from Days rather than as collectible pages. Hopefully it will be worth the wait on our part and the hardships on the part of the characters.
All The Reports
- Ansem Reports - The Keyhole: Ye Olde Kingdom Hearts Fansite
Ansem's Report is a series of pages collected throughout Kingdom Hearts and Kingdom Hearts II... (Scroll to the end for links to the other Reports)