The Substance Between

In early 2022, after more than a decade trying to find something to ease my mental suffering, I started using the psychedelic medication esketamine under the direction of my doctors. My experiences on this medicine continually challenges my perspective on my own mind and my relationship to the world around me, often in ways that language fails to capture.

Thinking now about how to focus what I want to write here, I was reminded of one of my earlier ketamine sessions, which struck me with its ineffability:

Session 6

… I decided to use a playlist that was much more energetic for the background to Session 6, which produced wonderful effects. This session again started with vivid closed-eye visualizations, facilitated by a meditative, trance-like state. I tried to intervene actively with my mind in the evolution of these sights much less than I did in Session 5; this time, I was more curious to see what would unfold. At first, my mind gravitated toward the idea of relaxation; “this is like a day at the spa”, I remember thinking to myself, a day to get away from the “work” of previous sessions, a day to relax and unwind with the medicine.

That quickly changed. In one scene, I saw from a primordial galaxy a dark-purple grid emerge on a lighter-purple background, and this grid began to warp in different ways—something like a 3D projection of curvature in spacetime. I began to feel myself pulled into the warped sections of the grid—and as I entered, I could physically feel myself, my arms, legs, toes, and fingers, be pulled in different directions.

My PhD work is in understanding the interactions between two different types of cells in the brain: on the one hand, neurons, which are more “excitable” cells that will completely flip on for a millisecond or so if one part is given the right input signal by one of their cousins; and on the other, astrocytes, which have much slower (and much less “all-or-nothing”) activations that shape, over seconds to minutes, the ways in which neurons are able to talk to one other. In this moment, I imagined the coupling between these two types of cells, as if it were the pull of gravity, the curvature of spacetime. Though I couldn’t picture it in my sight, I felt for a moment an intrinsic understanding of what it is for two things to be coupled, the “substance” that binds them together. I imagined becoming that substance; I imagined my body becoming the entity that warped purple grid represented. I could feel my limbs subsuming the connection between these two physical bodies.

As I delved deeper into space, I emerged in what looked like a microscopy image of cortical brain tissue, with neurons labeled in green and astrocytes labeled in red. As I flew through this 3D picture, I felt a shiver throughout my body; it was as though I could see the whole picture of brain function, as though I had stepped into a wider and more astounding world. In my mind I truly likened this moment to a religious experience.

After the visuals subsided, I tried to process the meaning of what I had just experienced for another hour and a half, writing:

I am the tension.
I am the substance between.

These words swirled in my head, but seemed almost mystical in quality. The feeling I had wasn’t something that I could formalize or operationalize in the moment. The visions themselves weren’t even particularly novel. But these scenes had a feeling of isness that made them powerful. I didn’t just know the mathematical object representing spacetime curvature; I became it. What it meant, I couldn’t say; but, I knew that it was meaningful.

I can’t comprehend the depth of a mind, the immensity of a lifetime of experiences. We look to the unknowable vastness of the cosmos beyond our planet to humble ourselves; and yet, the mundane act of perceiving the taste of my morning cup of coffee seems to rely on an equally mysterious force—the mind, the galaxy within, molded by innumerable moments imperceptibly pulling and pushing every aspect of the world I know in each moment.

The one tool we have at our disposal to transmit the contents of a mind is the story. Stories are the hereditary material of mental data, the means through which those data — memes, in the original sense — are replicated and transmitted. Stories are the mirror through which we might see the mind of another, dimly.

Since that session I have held on to that phrase, the substance between, as a convenient conceptual shortcut to encapsulate my evolving view on stories. In a world made of stories, the energy that serves as the motive force for all things stems from tension—the opposition of many “true” yet nonetheless entirely contradictory stories. This tension is the scaffold that holds up the mental universe. To know one story is not enough to see the world as it is; to understand, we must be able to hold all of those contradictory stories at the same time, and know that what is is greater than these constituent parts. This is the substance between to me: the universe as it is—not the stories, but the tension that holds them together, their intricate relationality.

It is common for folks using ketamine to form and repeat these short phrases, capturing some idea they want to hold on to as the drug’s acute effects fade, because it can be almost impossible to commit every indescribable detail of the experience to memory. Like many of my takeaways from my body of work with ketamine, even after months of processing, I struggle to articulate this term’s meaning. But perhaps there is a way to express that meaning through stories, however imperfect each individual projection may be. For now, the substance between is the compass bearing for the world I wish to know.