I Am a Strange Loop

other objectors to self-reference took it. What remained with me, however, was the realization that some highly educated and otherwise sensible people are irrationally allergic to the idea of self-reference, or of structures or systems that fold back upon themselves.

I suspect that such people’s allergy stems, in the final analysis, from a deep-seated fear of paradox or of the universe exploding (metaphorically), something like the panic that the television sales clerk evinced when I threatened to point the video camera at the TV screen. The contrast between my lifelong savoring of such loops and the allergic recoiling from them on the part of such people as Bertrand Russell, B. F. Skinner, this education professor, and the TV salesperson taught me a lifelong lesson in the “theory of types” — namely, that there are indeed “two types” of people in this world.

CHAPTER 5

On Video Feedback

Two Video Voyages, Three Decades Apart

THE loop of video feedback is rich, as I found out in my first explorations with our family’s new video camera in the mid-1970s. A few months later, my appreciation of the phenomenon deepened considerably when I decided to explore it in detail as a visual study for my book Godel, Escher, Bach. I made an appointment at the Stanford University television studios, and upon arriving I found that the very friendly fellow there had already set up a TV and a camera on a tripod for me to play around with. It was a piece of cake to point the camera at the screen, zoom in and out, tilt the camera, change angles, regulate brightness and contrast, and so on. He told me I was free to use the system as long as I wanted, and so I spent several hours that afternoon navigating around in the ocean of “taboo” possibilities opened up by this video loop. Like any curious tourist, I snapped dozens of photos (just black-and-white stills) during my exotic trip, and later I selected twelve of my favorites to use in one of GEB’s dialogues.

Since that first adventure in video feedback, three decades have passed and technology has advanced a bit, so for my new book I decided to give it another shot. This time I was aided and abetted by Bill Frucht, who, because of (or in spite of) being my editor at Basic Books for a dozen years or so, has become a good friend, and who flew in from New York just for this purpose. Together in my kids’ old “playroom”, Bill and I spent many delightful hours sailing the same old seas but in a somewhat newer craft, and we wound up with several hundred color snapshots that archived our voyage superbly. Aside from the cover illustration, sixteen of my favorites, covering a wide range, can be found in the color insert.

Although both video voyages were vivid and variegated, I decided for this chapter to write up a “diary” of the earlier one, undertaken long ago at Stanford, since that’s when I first explored the phenomenon and learned about it step by step. So the story below involves a different television, a different TV camera, and in general an older technology than was used in making this book’s color insert. Nonetheless, as you will see, much of the old diary still pertains to the newer voyage, though there are a few small discrepancies that I’ll mention when I come to them.

Diary of a Video Trip

There happened to be a shiny metallic strip running down the right side of the TV set I was given, and the presence of this random object had the fortuitous effect of making the various layers of screens-within-screens easily distinguishable. The first thing I discovered, then, was that there was a critical angle that determined whether the regress of nested screens was finite or infinite. If I pointed the camera at the metal strip instead of the center of the screen, this gave me what looked like a snapshot of the right wall of a long corridor, showing a few evenly spaced “doorways” (which actually were images of that metal strip), moving away from where I was “standing”. But I was not able to peer all the way down to the end of this “corridor”. I’ll therefore call what was visible on the screen in such a case a truncated corridor.

If I slowly panned the camera leftwards, thus towards the center of the screen and perforce further down the apparent corridor, more and more doorways would come into view along the right wall, smaller and smaller and farther and farther away — and all of a sudden, at a critical moment, there was a wonderful, dizzying sense of infinity as I would find myself peering all the way down the corridor toward a gaping emptiness, stretching arbitrarily far away toward a single point of convergence (the “vanishing point”, as it is called in the theory of perspective). I’ll call this an endless corridor. (Note that essentially this same kind of corridor is also visible in the photo of the self-reflecting mirrors in Chapter 4.)

Of course my impression of seeing an infinite number of doorways was illusory, since the graininess of the TV screen and the speed of light set a limit as to how many nestings could occur. Nevertheless, peering down what looked like a magically endless corridor was much more enticing and provocative than merely peering down a mundanely truncated corridor.

My next set of experiments involved tilting the camera. When I did this, each screen obediently tilted at exactly the same angle with respect to its containing screen, which instantly gave rise to a receding helical corridor — a corridor that twisted like a corkscrew. Though quite attractive to the eye, this was not terribly surprising to the mind.

An unanticipated surprise, however, was that at certain angles of camera twist, instead of peering down a helical corridor punctuated by doorways, I seemed to be looking at a flat spiral resembling a galaxy as seen through a telescope. The edges of this spiral were smooth, continuous curves of light rather than jagged sets of straight lines (coming from the edges of the TV screen), and such smoothness mystified me; I saw no reason why a sudden jump from jagged corners to graceful curves should take place. I also noticed that at the very core of each “galaxy”, there was nearly always a beautiful circular “black hole”. (On our more recent video voyage, Bill and I were unable to reproduce this “black hole” phenomenon, to our puzzlement and chagrin, so you won’t see any black holes in the photos in the insert.)

Enigmatic, Emergent Reverberation

At some point during the session, I accidentally stuck my hand momentarily in front of the camera’s lens. Of course the screen went all dark, but when I removed my hand, the previous pattern did not just pop right back onto the screen, as I expected. Instead, I saw a different pattern on the screen, but this pattern, unlike anything I’d seen before, was not stationary. Instead, it was throbbing, like a heart! Its “pulse rate” was about one cycle per second, and over the course of each short “heartbeat”, the shapes before my eyes metamorphosed greatly. Where, then, had this mysterious periodic pulsation come from, given that there was nothing in the room that was moving?

Whoops — I’m sorry! What I just wrote is a patent falsity — there was something in the room that was moving. Do you know what it was, dear reader? Well, the image itself was moving. Now that may strike you as a fatuous, trivial, or smart-alecky answer, but since the image was of itself (albeit at a slight delay), it is in fact quite to the point. A faithful image of something changing will itself necessarily keep changing! In this case, motion begat motion endlessly because I was dealing with a cyclic setup — a loop. And the original motion that had set things going — the prime mover — had been my hand’s motion, of which this video reverberation now constituted a stable, self- sustaining visible memory trace!

This situation reminds me of another loopy phenomenon that I call “reverberant barking”, which one sometimes can hear in a neighborhood where many dogs live. If a jogger passes one house and triggers one dog’s