The Noosphere is a theoretical realm created and maintained by the collective unconscious of all species involved with the Lux Aeterna. Put in other words, the Noosphere is a "place" that contains every concept, thought, or idea that can be created by these certain species. Every single possible state that the Lux Aeterna could exist in is represented within the Noosphere. The vast majority of intelligent species within Via Aylathiya and Azurullya exist comprising the Noosphere, causing what would normally be very alien thought-processes and cultures to share fundamental elements absent across most of the universe.
First hypothesis to exist in 71,031 CE by Yvonne Gauis, the Noosphere hypothesis offered an explanation for the origin of The Seekers as well as a potential origin for the Engels. While many other theories sought to explain the lack of variety in Aylathiya, most made heavy use of assumptions. For instance, Aeterna Theory assumed that intelligent life could only exist in a way that caused these similar psychologies. The existence of the Dotsk as well as other species, discovered later such as the Aldorians, would challenge the idea that there was only one way to evolve intelligence. As Aeterna Theory was abandoned in favor of Quantum Consciousness, a holistic theory devised to not only explain the Lux Aeterna using purely quantum means, but also explain why the vast majority of Aylathiyan life seemed to convergently evolve a common brain architecture.
After the turn of the sixty first millennium, advances in thaumic science would eventually lay waste to the Quantum Consciousness Theory, establishing once and for all that the Lux Aeterna was not composed of mere quantum particles, but of something fundamentally different, concepts themselves. The best analogy is as follows: think back to the last time you had a dream. You were there, and perhaps there were people, the sky, trees, or something else. These things in the dream do not obey any rules except for how the brain expects them to behave abstractly. The material within the Lux Aeterna is made up of "dream stuff," called Aeternal Energy. Many hypothesize that dreams, or more broadly thoughts as a whole, are composed of Aeternal Energy as well.
The most compelling observation confirming the existence of a Noosphere is the existence of what are known as "Extra-Noospheric Concepts," or concepts that exist outside of the set of ideas "allowed" in the Noosphere. The true forms of Engels, higher dimensional space, and certain "creatures," for a lack of a better term, exist outside of the Noosphere and are therefore incomprehensible to every species in Via Aylathiya save for one, the Dotsk. Experiments consistently show Dotsk capable of easily understanding and communicating amongst themselves about concepts that, when described to non-Dotsk, seem contradictory, impossible, or so abstract that no clear visualization can be grasped.
Currently, the Noosphere Theory acts as the basis for what is known as Cybersphere theory, an even newer idea that bridges quantum mechanics and Noosphere Theory.
Noospheric Disturbances are self-propagating conceptual constructs that exist entirely within the Noosphere but manifest within reality. They are, in other words, "boogie men" or "monsters" that haunt the deepest part of collective thought. The most prominent example of a Noospheric Disturbance was the Inheritence War, in which the nations of Via Aylathiya set aside their differences to fight against what the Dotsk described simply as "ghosts." The disturbances, known as The Seekers, were so intense that the many Magi across the galaxy began subconsciously using their power to manifest these beings within reality. In other words, all of Via Aylathiya became so convinced that these things were real that they became real and invaded the galaxy.
Some posit that Engels are also Noospheric Disturbances. The most troubling aspect of Noosphere Theory is that, realistically, most of the cosmos could be a hallucination by the Aeternal Species, so intense that the Lux Aeterna manifests them as real. One could go further and posit that the whole cosmos is a hallucination created by one all-powerful magi and the Lux Aeterna, existing so long as they are convinced that it is real.