In simplest terms, nonduality is the absence of opposites, meaning literally; “not two.”
As humans, we exist in a continual state of duality by our very nature; there’s good/bad, god/devil, happy/sad, love/hate, and everything in between. “For every action, there is an equal and opposite reaction.” is one of those phrases that’s etched into our mutual consciousness from a very early age. It expresses the very essence of duality in terms of the nature of this reality. Nonduality is the experience of the release from linear time and pairs of opposites into a state of consciousness where there only unity and love for oneself, each other, and God, the Divine, the Universe, our Beloved, or whatever term works best for you. It’s knowing, at the very core of or humanity that we’re all both a manifestation of and an expression of the Divine. Most of us have just been conditioned out of knowing that or remembering that, and it’s at the core of all of our feelings of disconnect from God, from each other, and from our own Selves.
As Wei Wu Wei succinctly said; “I Am but there is no me.”
Again, the word itself means “not two.” It’s the perfect expression of unity. When we apply that to spirituality, it means “oneness with god.” The Upanishads were among the first to write about it and called it “advaita” which literally translates into “non-dual.” According to a famous philosopher and expert on non-duality called David Loy, when you realize that the nature of your mind and the Universe are nondual, you are enlightened. Or, one of my favorite expressions of nonduality reminds of some of the greatest Zen teachings. Tim Gerchmez said; “Would you mind terribly if I threw nonduality to the wind for a moment, and just said that I love you?”
Rumi, to me, basked in the glow of nonduality, so I highly recommend “The Way of Passion” by Andrew Harvey for an entire book of definitions regarding nonduality. From everyone I’ve spoken with and from my own personal experience with the timelessness of nonduality, to me, it’s the highest expression of love that humans are capable of experiencing. We begin our lives in the oneness of the womb, in a perfect state of nondual existence with our personal Mother Goddess. Genesis and the Garden of Eden is the perfect expression of this state of existence, as god, human, plant and animal were one within the Garden of Eden.