--- title: "An interview with the phenomenologist Steven Lehar" authors: - name: "Cube Flipper" url: "https://twitter.com/cube_flipper" --- In summer 2025 I had some time to kill on the East Coast in between [Vibecamp](https://vibe.camp) and [The Science of Consciousness Barcelona](https://consciousness.arizona.edu/tsc-2025-barcelona-flyer), so I decided to take the Acela up to Boston for a long overdue meeting with the phenomenologist and vision researcher [Steven Lehar](http://slehar.com/wwwRel/Lehar.html). Lehar has a PhD in Cognitive and Neural Systems from Boston University, where he studied under the well known cognitive scientist [Steven Grossberg](https://en.wikipedia.org/wiki/Stephen_Grossberg). He's also the rational psychonaut's *rational psychonaut* – early in his career he discovered that psychedelics such as LSD could be used to deliberately alter subjective experience in a way that he believed was useful for understanding the human vision system and by proxy consciousness. Very briefly, you could say that his core claim is that [the brain operates as a harmonic resonator](https://www.youtube.com/watch?v=LJiXTCbFtu0), [constructing a fully volumetric world simulation which we navigate from the inside](https://qualiacomputing.com/2022/12/28/cartoon-epistemology-by-steven-lehar-2003/).
[![](/images/random/lehar/interview/Fig57A.jpg){ style="max-width: 200px; width: 100%" }](http://slehar.com/wwwRel/cartoonepist/cartoonepist25.html)
One of Steven Lehar's iconic "bubble world" sketches, from his book [A Cartoon Epistemology](https://qualiacomputing.com/2022/12/28/cartoon-epistemology-by-steven-lehar-2003/).
Due to the subjective nature of his claims, journals repeatedly rejected his papers – and so he resorted to publishing his ideas on his [personal website](http://slehar.com/wwwRel/Lehar.html). He has also published a handful of books, including an autobiographical account of his psychonaut career titled [The Grand Illusion](http://slehar.com/wwwRel/GrandIllusion.pdf) (2010). Personally, I think his claims were ahead of their time – it's just a shame that scientific academia has not yet found a home for his kind of phenomenology. I have found his models of perception to be pretty accurate in the sense that they have formed the foundation of my own view of subjective experience – and I even wrote a [three part review](/posts/2025-10-18-three-year-retrospective.html#phenomenology-1.1-lehars-frameworks) of his ideas to help introduce them to a wider audience. We cover a lot of ground in this interview – Lehar's early LSD experiences and how they shaped his models of perception; his time at Boston University and the difficulties he had publishing his research; and some very nerdy discussion of psychedelic and dissociative phenomenology. This has been a long time coming; I hope you enjoy it as much as I did.
A conversation with Steven Lehar at his home in Massachusetts, about human vision, psychedelic phenomenology, and the world in your head. Video recorded on 2 July 2025.
Steven Lehar demonstrates his bubble world diorama and Kanizsa triangle, which he used to help communicate his theories of human visual perception and the concept of [indirect realism](https://en.wikipedia.org/wiki/Direct_and_indirect_realism). Video recorded on 2 July 2025.
--- ## Links **Websites** - [slehar.com](http://slehar.com/wwwRel/Lehar.html) - [slehar.wordpress.com](https://slehar.wordpress.com) - [doubleconformal.wordpress.com](https://doubleconformal.wordpress.com) - [perceptualoriginsofmath.wordpress.com](https://perceptualoriginsofmath.wordpress.com/) - [youtube.com/@slehar](https://www.youtube.com/@slehar) **Books** - [A Cartoon Epistemology](https://qualiacomputing.com/2022/12/28/cartoon-epistemology-by-steven-lehar-2003/) (Lehar, 2003) - [The World in Your Head: A Gestalt View of the Mechanism of Conscious Experience](http://slehar.com/wwwRel/webstuff/book/WIYH.html) (Lehar, 2003) - [The Boundaries of Human Knowledge: A Phenomenological Epistemology](http://slehar.com/wwwRel/webstuff/book2/Boundaries.html) (Lehar, 2004) - [The Grand Illusion: A Psychonautical Odyssey Into the Depths of Human Experience](http://slehar.com/wwwRel/GrandIllusion.pdf) (Lehar, 2010) **Papers** - [Harmonic Resonance Theory: An Alternative to the "Neuron Doctrine" Paradigm of Neurocomputation to Address Gestalt Properties of Perception](http://slehar.com/wwwRel/webstuff/hr1/hr1.html) (Lehar, 2000) - [The Constructive Aspect of Visual Perception: A Gestalt Field Theory Principle of Visual Reification Suggests a Phase Conjugate Mirror Principle of Perceptual Computation](http://slehar.com/wwwRel/ConstructiveAspect/ConstructiveAspect.html) (Lehar, 2008) **Videos** - [Nondualita](https://www.youtube.com/watch?v=JQ51vrnbAHA) (Lehar, 2016) - [Do We Live in the Real World? (Harvard Science of Psychedelics Club)](https://www.youtube.com/watch?v=WPZ9WMvtbi0) (Lehar, 2019) - [Harmonic Gestalt: Sound from Structure – A Holistic Invariant Representation of Spatial Structure Through Sound as a Model of Perception](https://www.youtube.com/watch?v=LJiXTCbFtu0) (Lehar, 2022) **Blog posts** - [Free-Wheeling Hallucinations](https://qualiacomputing.com/2019/01/06/free-wheeling-hallucinations/) (Gómez Emilsson, 2019) - [Welcoming Steven Lehar as a QRI Lineage](https://qri.org/blog/steven-lehar-lineage) (Gómez Emilsson, 2021) - [An introduction to Steven Lehar, part I: Bubble worlds and force fields](/posts/2022-10-01-an-introduction-to-steven-lehar-part-i.html) (Flipper, 2022) - [An introduction to Steven Lehar, part II: Symmetries and periodicities](/posts/2022-11-22-an-introduction-to-steven-lehar-part-ii.html) (Flipper, 2022) - [An introduction to Steven Lehar, part III: Flame fronts and shock scaffolds](/posts/2023-01-18-an-introduction-to-steven-lehar-part-iii.html) (Flipper, 2023) **References** - [Psychedelics and Mathematical Vision – McKenna, Abraham, Sheldrake Trialogue](https://www.youtube.com/watch?v=jvrvUNtn85s) (Abraham, McKenna & Sheldrake, 1992) - [Brain Mechanisms of Vision](https://mechanism.ucsd.edu/bill/teaching/w20/phil151/Hubel_Wiesel.brainmechanismsofvision.1979.pdf) (Hubel & Wiesel, 1979) - [Shufflebrain: The Quest for the Hologramic Mind](https://www.amazon.com/dp/0395294800) (Pietsch, 1981) - [Nonlinear Optics](https://www.amazon.com/Nonlinear-Optics-Robert-W-Boyd-dp-0128110023/dp/0128110023/) (Boyd, 2020) - [Traveling Waves Integrate Spatial Information Through Time](https://arxiv.org/abs/2502.06034) (Jacobs et al., 2025) - [Human brain networks function in connectome-specific harmonic waves](https://www.nature.com/articles/ncomms10340) (Atasoy, Donnelly & Pearson, 2016) - [The Devil's Staircase](https://aip.brightspotcdn.com/PTO.v39.i12.38_1.online.pdf) (Bak, 1986) - [A Primer on the Symmetry Theory of Valence](https://opentheory.net/2021/07/a-primer-on-the-symmetry-theory-of-valence/) (Johnson, 2023)