The way Tolle refers to Being or Presence is like the definition of the Aether: an infinite, eternal background or substratum. In other words, the Aether, Being, and Presence can all be interchangeable terms.

I see a unity of knowledge taking place in the early 21st century, using natural law to form links between all disciplines (physics, biology, the arts, philosophy, and all of human science). The overwhelming evidence points to a powerful, non-material, environmental force known as the Aether, that is the unified field, and is the Consciousness that conserves and conveys the memory of the Universe. Besides being the basis for physical reality, the Aether is Universal Consciousness, the medium of mind and the memory of thought and emotion. This concept allows us to realize that our identities are like islands in an ocean. We feel separated, but we are actually connected at a deep level. Anyone can incorporate the Aether into their philosophy, and it becomes a Rosetta Stone of understanding for them.

As an example, the basic concept of "The Secret", is that what you focus on, with thought and feeling, is what you attract into your experience (what you visualize is what you materialize into your life). The authors refer to a "Universal spiritual field", and talk about the definition of God and the definition of energy as being close to the same thing - that we are all part of an infinite field. I think the knowledge of the Aether is "the secret of The Secret". In other words, we directly "hack into" reality at the quantum level as we focus on what we want to experience, instead of just letting life happen to us. We attract our success and ideal lifestyle by sending out vibrations that become our reality. Thoughts become things.