I had myself a fun read with Dr. I. M. Levitt’s 1956 offering, A Space Traveller’s Guide to Mars, a book which consolidates all the very latest knowledge about the planet Mars—or at least all the latest knowledge in the McCarthy era, when science could promise anything, including certainty, and Buck Rogers was more real than Ho Chi Minh. Along the way, my reading spawned two (possibly) related thoughts, one about perception, the other about history.
In surveying what was known and what could reasonably be surmised about Mars, Levitt touched on the canals. In 1877, an astronomer from Milan named Schiaparelli first observed markings on the planet’s surface which he named canali, meaning channels. This touched off a controversy amongst astronomers that was probably influenced as much by professional rivalries and the desire to see evidence of intelligent design as it was by reliable observation. Over time, astronomers “reverse engineered” their observations and concluded that it was a perceptual phenomenon—random markings on the planet’s surface appeared to be organized into well-defined patterns. Levitt concluded: “Markings at the very limit of visibility are more or less unconsciously patterned into nonexistent lines and geometrical figures. If the observer wishes hard enough to see artificial markings, he can see them …” I think it’s relevant to note that Schiaparelli was a priest, a man conditioned to believe.
The brain has a remarkable capacity to “fill in the gaps.” This is how we see. It has something to do with fixation and saccade. I don’t understand these phenomena, but you can learn everything you ever wanted to know about the psychophysics of vision here. As I understand it, there are certain limitations to our visual acuity. Some are a function of our physiology. For example, we have a blind spot in each eye. To compensate, the brain fills in the gap to create continuity with the colours/patterns of adjacent spaces. Follow the link to see illustrations of how this works. Other limitations are a function of the way our brain copes with visual data. For example, cognitive optical illusions like the Müller-Lyer illusion demonstrate how assumptions about the world interact with data to produce visual distortions. We know this illusion is based on cognitive assumptions because it has less effect on non-Western viewers. It is more likely to fool people who are accustomed to live in surroundings with the rectangular architecture that typifies European and North American cities.
The brain’s capacity to fill in the gaps is also evident in the way we process auditory information. This phenomenon is explained through the discipline of psychoacoustics. An example of this is the “missing fundamental.” If you remove the lowest note(s) in a sound made up of a harmonic progression, the brain will still hear the pitch based on the missing note(s).
Music compression algorithms take advantage of other “gap filling” habits. For example, a CD quality sound is sampled at 44.1 KHz i.e. the music is produced by sampling analog sound 44,100 times each second. The brain then constructs these digital bits of audio information into waveforms. But a simple compression algorithm (e.g. an mp3 file) can reduce the size of the audio file by 90% by removing 9 of every 10 samples and the brain will still construct waveforms which approximate those it “heard” when listening to the CD quality sound. Most people can’t tell the difference between music sampled at 44.1 KHz and 4.41 KHz because the brain constructs waveforms that sound “right” in both cases.
Martian canals belong to this class of perceptual phenomenon. In a world conditioned to expect the discovery of alien life, it was natural for even the most seasoned scientific observers to presume that they were seeing evidence of intelligent Martians. Even after the canal theory had been put to rest, the general public could still be persuaded that Martians were attacking the planet Earth although they had been advised that they were listening to a piece of fictional radio drama.
And notwithstanding the debunking, Levitt, a skilled scientist and director of the Fels Planetarium in Philadelphia, still concluded that the vague splotches which had been the basis for the canal observations were nevertheless definitive proof of vegetation growing on the Martian surface. Our propensity to believe is more powerful than we credit!
This leads me to the second strand of thought which Levitt’s book spawned. In fact, it wasn’t the book so much as my response to it which gave rise to my next consideration. I found myself regarding the book with a patronizing smile. Isn’t it funny, I thought, how they could conclude that the atmosphere is made up of 96% nitrogen when our probes have discovered that its atmosphere is 95% carbon dioxide, how they could conclude that there is plant life on Mars when we know better than to jump to rash conclusions, how they could project a timeline that would see a moon landing in 2000 when we did it in 1969. I think many of us entertain a patronizing attitude towards the past which betrays our own assumptions – most notably our assumption that the human trajectory is characterized by progress. Here is a sampling of the many kinds of progress we perceive:
• temporal – we progress through time
• historical – our political and social structures are better than they were, say, in ancient Egypt or pre-industrial England
• scientific – we know more now than we did a hundred years ago
• technological – how could we have ever survived before the iPod and the internets?
• economic – we have more wealth per capita than we did before TNC’s become our major economic players
• moral – we are basically good people moving towards a state of better relationship with others and the natural world
Levitt’s book most obviously draws attention to scientific and technological progress, although each category of progress tends to bleed into the others. Levitt was writing at the height of McCarthyism when America’s competition with Russia to dominate space was a symbolic assertion of a uniquely American historical destiny. Scientific and technological progress fed a historical perception of progress. This was reinforced by an economic perception that viewed capitalism as ushering in a new world order. There was (and, for many, continues to be) an inevitability to this account. This is further tied to moral progress. Democracy treats the individual as the basic and essential component of the political order, just as the individual (as consumer) is the basic and essential component of the economic order. For the new order to optimize the well-being of all, each individual must assume moral responsibility for his role as a fundamental political and economic unit. I don’t propose to offer a compelling or coherent narrative of progress, but only to demonstrate that it is possible for one category of progress to bleed into another.
However, thinking on the canali, it occurred to me that perhaps my paternalistic attitude towards the past—an attitude that incorporates cultural assumptions about progress—is as much an illusion of historical optics and the canali were an illusion of Schiaparelli’s astronomical optics. Maybe my mind is conditioned to see patterns where a closer examination would reveal nothing more than unrelated blobs and surface scratchings. What I view as a coherent historical narrative which progresses from the past, through a point in the present, and which projects along a straight line into the future, is simply a construction produced by the perceptual quirks of my own brain and ratcheted by my desire to believe earnestly in an orderly universe.
Is there any relationship between significant events of the 20th century? Consider the Russian revolution, the Holocaust, the Cultural Revolution, India’s independence, the internal combustion engine, the transistor, the assembly line, Hiroshima. Can these be drawn into a coherent narrative? Levitt discarded the canali theory and found that the underlying blobs and markings were really evidence of plant life. If, like Levitt, we discard a cherished theory, do we nevertheless expose ourselves to the temptation of replacing it with another equally misinformed narrative? Maybe it’s more prudent to learn how to live with incoherence.