Ancient people believed that all beings reproduced themselves through the energy of Aether.
Considering Aether to be the key to creating life, Ancient alchemists focused on extracting pure Aether in liquid form for that purpose.
Though their knowledge has largely been lost, golems and gargoyles would seem to be the results of these efforts.
Though animate, these creatures are not quite alive. I would assert therefore that Aether is not a simple chemical component of life.
Modern thinking on Aether dates from the age when the Aetheric Field protected Humans from the Balaur.
It was then that scholars came to theorize Aether's spiritual properties. Lumiel, the Empyrean Lord of Wisdom, created an academic definition of Aether that is still considered the most accurate.
Aether, as a spiritual force, is present in all things in the world. It represents the physical manifestation of Aion and his harmonious influence on all living things.
It is my contention that Aether is the mechanism by which Aion works his will in the world. Aion--a fundamentally unknowable being, is not a part of our reality, and created Aether as an intermediary to interact with our world.
Certainly divine creations like Aion's Tower and the Aetheric Field contain high concentrations of Aether. Changes in Aetheric flow can effect massive changes to the climate of an entire region, as Eltnen demonstrates.
The process of ascension has not been scientifically studied, but I hypothesize that Humans ascend as the result of a large infusion of Aether.
All living beings seem to have some innate skill at handling Aether. The powers that Daevas display are simply the highest level of that ability.
There have been notable examples of famous crafters who never ascended, but were still capable of great Aetheric skill, using it to produce wonderful transmutations in their works.
The ability to manipulate Aether on a large scale, however, may be outside the reach of mortal abilities, remaining the provenance of Aion and his chosen servants, the Empyrean Lords.
The practical uses for manipulating Aether are many. Soul healers control Aether flow in living beings. Their vows forbid them from using this ability for harm, however.
Almost all crafting processes use Aetheric manipulation in some way, and the application of pure Aether can be used to create higher-quality goods.
Aether may be able to transmute living beings, as in the process of ascension. The Drakan may have discovered just such a process when they became the Balaur, although obviously I could not verify this assertion without asking a Dragon Lord.
Perhaps the most curious manifestation of Aether is Stigma Stones.
They may be the spiritual remnants of Daevas who have suffered Vanishment--death without resurrection, their spiritual essence in some way becoming solid Aether.
Stigma Stones contain some portion of the knowledge and skills the Daeva had in life, which suggests that Daevic souls are strongly infused with Aether.
Perhaps further study of Stigma Stones will be the key to unlocking the mysteries of the world.