I sit down to meditate.
My eyes close, I indulge in any fidgets my body feels it needs to make, and I find stillness, spine lengthened. I am aware of my body - the contact points with the floor; where my hands meet my legs; the clothes on my skin. I begin to become so still that the boundaries of my physical body slowly fade. My awareness draws within. I start to become more aware of my breath - now my connection between internal and external. I'm breathing through the nose, into and out of the belly, slow, passive breaths. I begin to notice my heart beat in my chest, and with my earplugs in I can feel and hear it. My physical existence simply my breath and heartbeat. I am the first state of consciousness - the waking state; I am the gross body; I exist; absolute reality - Sat.
With my eyes closed the physical world, internal and external, ceases to exist. I become aware of my thoughts. There are so many. As soon as one finishes the mind jumps to the next - never a moment of relief. The mind drifts to the past, reliving (or at least reconstructing through the lens of the ego) things that have happened that clearly still have a hold on my subconscious. Mostly bad/negative, or problems I've dealt with and question if I did the right thing, but sometimes happy moments also. The mind drifts to the future, anticipating problems I'm aware are forthcoming, playing out scenarios over and over to predict every possible outcome; or fantasizing about how my life could go, or even how I want it to go. Reality becomes whatever thought is current, so reality is infinite, with boundless possibilities, and each one real because my mind is living in and experiencing it right now, even if my physical body isn't. I am the second state of consciousness - the dreaming state; I am the subtle body; I perceive/I know; pure awareness - Cit.
Eventually I grow exhausted experiencing every thought, repeatedly, and I begin to notice that I'm thinking. I start to notice these thoughts, that I'm having them, and that I've had them before. I become so aware of my thoughts that I begin to watch them instead of live them, and I begin to better understand myself. Here time slows down, and I notice the thoughts slow also, and for the smallest fraction of a moment I witness a space between two consecutive thoughts. I start to question what exists in this space, and I actively seek it. I employ the use of a mantra ('mind tool') - a word or phrase (preferably Sanskrit) - and repeat it over and over, focusing the mind into a state of intense concentration where the mantra loses meaning - I become undifferentiated form, emptiness, ignorance (avidya). This space between thoughts, where the sense of 'I' becomes fundamental, giving origin to the ego. Who am I when I'm existing in this moment? I am the third state of consciousness - the deep sleep state; I am the causal body; I am bliss; unconditioned joy - Ananda.
But in this space there is still a residual sense of 'I' from which these layers of consciousness develop. But what exists beyond this space? Turiya - "the fourth". The fourth state of consciousness - the background that underlies and transcends the three common states of consciousness; waking up in dreamless sleep. The state of being one with the self, where time ceases to exist. I am Atman - pure consciousness. The purest expression of the universe, the true self/inner self/soul, beyond identification. I begin to witness Brahman, the Ultimate Reality of the Universe - the infinite and eternal: that which does not change yet is the cause of all changes. Here, Brahman meets Atman. My existence is the same as everything else that exists - the stuff that makes me is the same stuff that makes everyone and everything else. I am both unique (one) and same (many). I am simultaneously a separate expression of the universe, and a part of it. Just as you cannot separate a wave from the ocean, I understand that I am simultaneously individual and universal - I am both the ocean and the wave. Here, where Brahman meets Atman, is not oneness, but union. To be One, by definition, there ceases to be the existence of two; in Union, it is merely where the two connect.
I am Aum.