It seems to me two things are happening. [1] The brain is really good at filling in gaps in its perception of the world and [2] there seems to be some kind of strange loopy recursion in the way the brain analyzes and observes things including itself.
I think on DMT and similar, you are actually seeing less of the world, and the recursive/fractal aspect is coming from the brain filling in gaps with observations including its own analyzing patterns.
The world at our scale has a lot of data and is really complex. These "hypbolic geometries" seem like simplifications. One strand of a flower that happens to follow something roughly like the golden ration becomes a fibonacci spiral repeated at every degree; the sense of self gets muddled with the modeling of this pattern, allowing the pattern to permeate the entire observation, and now you too are the spiral. You notice the observation and how muddled it is with the pattern and the self, creating a loop which also gets modeled, and down the recursive rabbit hole you go.
Pure speculation, but I have to wonder if our fundamental conception of sensation as a blank canvas slowly filled with positive contents is wrong, and rather that perception involves the apprehension of difference against some "basic" recursive pattern.
I tend to notice this more aurally, in the sonic experience within a highly focused state, including spending time on social media (not silent! quite noisy, but I am not actively aware of it in most cases), and also the intense experience of hitting the stop button mid-song; the silence hits very hard.
Seems Fristonian, in that if the brain is a prediction machine across time, then the underlying predictive pattern would be fractal, or at least highly self-similar to immediate past experience. The intensity of the hard stop (and similarly the annoyance of transient sounds like car horns) is in the predictive failure, which draws your attention. If this is desirable, we call it "interesting".
And if you consider the oscillatory nature of the brain, it is awfully easy for a massive set of weakly coupled oscillators to produce highly patterned nonlinear effects. We usually hold these things in control by virtue of our familiarity with them. But when they shift into some different oscillatory modes, the novel patterns become apprehensible.
For instance:
Atasoy, S., Roseman, L., Kaelen, M., Kringelbach, M. L., Deco, G., & Carhart-Harris, R. L. (2017). Connectome-harmonic decomposition of human brain activity reveals dynamical repertoire re-organization under LSD. Scientific reports, 7(1), 1-18.
Ah, Carhart-Harris! His paper with Karl Friston, "REBUS and the Anarchic Brain: Toward a Unified Model of the Brain Action of Psychedelics" (2019) really stuck with me. Very interested in harmonic interpretation, thank you for sharing.
You’ve beautifully articulated a feeling I’ve had for most of my life. In the Alvin Maker (historical fantasy) series, Orson Scott Card describes a phenomenon he calls the _greensong_. It’s a sort of pervading communion the first peoples have with nature, and white settlers not only can’t connect with it, but exist as a palpable disturbance to those who can. I’ve often felt like nearly _everything_ is signal, and my day-to-day experience is actually noise. That sense has been heightened on the occasions I’ve used hallucinogenics.
I think on DMT and similar, you are actually seeing less of the world, and the recursive/fractal aspect is coming from the brain filling in gaps with observations including its own analyzing patterns.
The world at our scale has a lot of data and is really complex. These "hypbolic geometries" seem like simplifications. One strand of a flower that happens to follow something roughly like the golden ration becomes a fibonacci spiral repeated at every degree; the sense of self gets muddled with the modeling of this pattern, allowing the pattern to permeate the entire observation, and now you too are the spiral. You notice the observation and how muddled it is with the pattern and the self, creating a loop which also gets modeled, and down the recursive rabbit hole you go.