One of the NPCs we can talk to is the Nihilistic Nibirun (he's talking to a Karellian), who seems to be reflecting on the recent events around them; that they wanted to be part of something larger than themselves, but pursued perfect understanding (and much the same doomsaying attitude that the Ea had when we met them) rather than realizing that, hey, maybe they could just sit down and talk to people. Which, yeah, they weren't doing before--they mostly just hung around the edges of the places we were going and saying to themselves 'hm, yes, we're right, everything should die'. The scene in Elysion is the first time they've bothered actually HAVING a conversation and listening to someone other than themselves.
There's also one hanging out with the Emotional Grebuloff with a speech bubble line that really helps explain that whole 'without negatives there are no positives': "We once had cuisine..." That's actually a pretty great, simple example of what they're trying to get across: if people didn't need to eat food, we wouldn't have needed to come up with good food. Like the Ea from a different direction, the Nibirun escaped the need to eat... so they eventually forgot the joy of a good meal.