I Am a Strange Loop

Well, it’s pretty clear that as musical notes sink lower and lower, the individual vibrations constituting them grow more and more perceptible. If you strike the leftmost key on a piano, you will feel very rapid pulsations at the same time as you (sort of) sense what pitch it is. Such a note is so low that we reach the boundary line between hearing it as a unitary pitch and hearing it — or rather, feeling it — as a rapid sequence of individual oscillations. The low “note” floats somewhere between singularity and plurality, somewhere between being auditory and being tactile. And if we had a piano that had fifteen or twenty extra keys further to the left (some Bösendorfers have a handful, but this piano would go quite a ways further down than they do), the superlow notes would start to feel even more like vibrations of our skin and bones rather than like pitches of sound. Two neighboring keys, when struck, wouldn’t produce distinguishable tones, but just low, gruff rumbles that felt like long, low, claps of thunder or distant explosions, or perhaps cars passing by with subwoofers blasting out their amazing primordial shaking rather than a singable sequence of pitches.

In general, low notes, as they sink ever lower, glide imperceptibly into bodily shakings as opposed to being pitches in a spectrum, whereas high notes, as they grow higher, do not do so. This establishes a simple and obvious objective difference between the two ends of the audible spectrum. For this reason, it is inconceivable that Diana Krall could have an inverted-spectrum experience — that is, could experience what you or I would call a very high sound when the lowest piano note is struck. After all, there are no objective bodily shakings produced by a high note!

Glebbing and Knurking

Well, all right. If the idea of a sonic inverted spectrum is incoherent, then why should the visual inverted spectrum seem any more plausible? The two ends of the visible range of the electromagnetic spectrum are just as physically different from each other as are the two ends of the audible sonic spectrum. One end has light of lower frequencies, which makes certain pigments absorb it, while the other end has light of higher frequencies, which makes other pigments absorb it. Unlike rumbles, though, those cell-borne pigments are just intellectual abstractions to us, and this gives some philosophers the impression that our experiences of redness and blueness are totally disconnected from physics. The feeling of a color, they have concluded, is just some kind of personal invention, and two different people could “invent” it differently and never be the wiser for it.

To spell this idea out a little more clearly, let’s posit that knurking and glebbing (two words I just concocted) are two vastly different sensations that any human brain can enjoy. All humans are created in the womb with these experiences as part of their built-in repertoire. You and I were born with knurking and glebbing as standard features, and ever since our cradle days, we’ve enjoyed these two sensations countless thousands of times. In some folks, though, it’s red light that makes them knurk and blue that makes them gleb, while in others it’s the reverse. When you were tiny, one of the colors red and blue happened to trigger knurking more often, while the other one triggered glebbing more often. By age five or so, this initial tendency had settled in for good. No science could predict which way it would go, nor tell which way it wound up — but it happened anyway. And thus you and I, dear reader, may have wound up on opposite sides of the gleb/knurk fence — but who knows? Who could ever know?

I must stress that, in the inverted-spectrum scenario, the association of red light (or blue light) with knurking is not any kind of postnatal wiring pattern that gets launched in a baby’s brain and reinforced as it grows. In fact, although I stated above that to knurk and to gleb are experiences that all babies’ brains come innately equipped with, they are not distinguishable brain processes. It’s not possible to determine, no matter how fancy are the brain-scanning gadgets that one has access to, whether my brain (or yours) is knurking or glebbing. In short, we are not talking about objectively observable or measurable facts about the brain.