Children piloting the EVA

[Snow]

Now, Children are used to pilot the Eva's, but adults are not. Is the reason behind this explained at all?

[Reichu]

The Evas were cloned from mother-goddess beings (Adam and Lilith) and seem to have an intrinsically maternal nature as a result. It seems possible that mothers are used for Evas because the Evas only accept this type of soul. This is implied by the circumstances of Kyoko's contact experiment: she resisted the core's pull, but Eva-02 still managed to absorb the "maternal part" of her soul. This limitation in the Evas could then result in the limitation upon viable pilots -- only those with a "child" relationship to the Eva's soul will be compatible, as a general rule.

It's harder to justify why both pilots and all pilot candidates are specifically 14 years of age. There's a popular notion that Second Impact is somehow responsible, but I've never seen a viable mechanic actually proposed, and without actual explanatory power this is just the usual conflation of correlation with causation.

[Snow]

Thank you for the answer. As there seems to be no official explanation for this, i'l take your theory as the most likely explanation. However, it could also be simply a very badly thought budgetary decision to save space inside the Eva's and thus reducing cost. But that seems extremely unlikely.

[pwhodges]

And ignoring the internals of the show, it also follows a history of children piloting mechas from Yuusha Raideen through Gundam and so on.

[sephirotic]

The Evas were cloned from mother-goddess beings (Adam and Lilith) and seem to have an intrinsically maternal nature as a result. It seems possible that mothers are used for Evas because the Evas only accept this type of soul. This is implied by the circumstances of Kyoko's contact experiment: she resisted the core's pull, but Eva-02 still managed to absorb the "maternal part" of her soul. This limitation in the Evas could then result in the limitation upon viable pilots -- only those with a "child" relationship to the Eva's soul will be compatible, as a general rule.

It's harder to justify why both pilots and all pilot candidates are specifically 14 years of age. There's a popular notion that Second Impact is somehow responsible, but I've never seen a viable mechanic actually proposed, and without actual explanatory power this is just the usual conflation of correlation with causation.

Asuka was 13 when she arrived in Japan.

I see 4 possible scenarios for the age and condition of the pilots.

The very first one is the one you already covered.
The second is simply the fact that teenagers are still fully developing their indetity so the border of their "souls" are not as well defined as adults.
The third is that all eva pilots must have been born AFTER the second impact due to some mechanics exclusively to that event.

And the fourth one is a more simple explanation: If a Eva has no soul and someone tries to get close to the core or even touch it, they would be instantly absorved by the Eva. From them on, the Eva would be the individual absorved with a new body itself. The reason why children is used is not because they are children, but because the person inside the Eva would reject and not want to partially sincronize (merge mentally) with a stranger, even if it is a known person. Only a mother-child relationship is symbiotic enough for both minds to accept joinning. This also links back to the scond hypothesis, as Teenagers have still to fully mature and kill their bond with their parents in Freudian therms.

Rei and Kaworu are of course special, but this apply to Shinji and Asuka.
I always wondered why Gendou never tried to sync with Yui, I always thought that was actually possible but somehow Gendou was
Patiently waiting for the moment he would merge with Unit 01 after his plans for attaining imortality were completed, with needed someone competent like himself getting rid of all the angels and Seele that were the only entities capable of stopping him.

Just my two cents.

[Reichu]

The mother-child thing was inspired in the first place by a program Sadamoto saw about the role of the A10 nerve in facilitating bonding. The examples I've seen cited are those between mother and child and those between lovers, though of course other kinds of intimate relationships are possible, and in any case NGE went exclusively for mother-child.

If Gendo could have been with Yui again in some way that was, unlike Third Impact, immediate and guaranteed, I have little doubt he would have attempted it. I find it simplest to think that this wasn't done because synchronization wouldn't work between equals. While similar to Instrumentality, synch is not exactly the same process. Gendo's soul and body did not come from Yui; short of elevating Yui to godhood and returning himself to "nothing", he has no way to become a part of her.

I have the notion that the Eva's ability to internalize a subordinate child-soul ("subordinate" because it IS the Eva's body and nothing happens if the Eva doesn't cooperate) is taking advantage of their underlying Seed nature. Seeds are designed to carry around any number of souls, all of which represent potential children. Shinji's been liquified in the plug twice, and Eva-00 was purportedly trying to absorb him as well -- oddities that might make more sense if we remember the Evas are made from Seeds, and thus may have a strong instinct / reflex to initiate the formation of a Chamber of Guf.

You bring up the Second Impact thing, but as I said this is useless without a proposed mechanism of action. But, honestly, what could it be? Most of the post-2I effects are mundane ecological disasters. The crazy metaphysical alterations are localized to the South Pole, and there is no evidence that Yui, Kyoko, et al. went down there and got "exposed".

[SoryuUberAlles]

I think the other 'Asuka Academy' argument is that Seele were planning for Eva pilots since the first contact experiment. As long as the best conditioned child is better than the gnarliest jarhead, so it will be. Frankly child soldier warfare is would be the least of their crimes.

[Reichu]

The Classified Information implies that pre-CE attempts to pilot the Evas were made, with the first contact experiment resulting from the realization that Evas couldn't work without their own souls. What the team THOUGHT would happen is that Yui's soul would be not absorbed, but copied to or imprinted upon the core. The results (Yui's absorption) were regarded a freak accident, and Kyoko tried again, only to have part of her soul devoured. The takeaway from both incidents was that a soul could not truly be copied.

I would guess that, with their plans foiled, Gehirn was forced to improvise. Eva-02 "selecting for" Kyoko's maternal qualities may have given them the idea to try seeing if there was any reaction between the Eva and Kyoko's daughter.