Footnote article: Interpreting Messages

Surfing The Net

In the mid 1990s, when I had the opportunity, I spent time 'surfing' the Internet from one of the free terminals kindly provided by Cambridge Central Library. On oc­ca­sions I took a few minutes out from the serious business of seeking information to assist in my vain search for work. During those moments I would sometimes call up the Web server of the United States National Aeronautics & Space Admini­stra­tion (NASA) and others. I would then download some of their amazing space pict­ures. Among my favourites were Earth-rise taken from the Moon and the Horsehead Nebula.

The picture materialised gradually on the screen as it was being downloaded over the Internet. However the picture did not appear in finished detail line-by-line as does a television frame. A fuzzy view of the whole object appeared almost immediately. As more of the informa­tion came across, the fine detail gradually filled in for the picture as a whole until a crisp high-definition view of the whole object was on the screen.

This is how I visualise the method I use to build up a detailed picture of what a 'difficult to understand' ancient text is trying to convey. However like any analogy it is only partial. The data transfer protocols and image display software running in the personal computer at Cambridge library don't have to apply any guesswork in order to abstract the precise meaning contained in the data arriving from Houston. They don't have to speculate as to what NASA's Web server intended the image to look like. My PC and NASA's server both use the same image file formats and trans­fer protocols. They speak the same language and interpret against the same 'cult­ural background'.

This is not so for a modern reader trying to gain a true picture of what the writer of a difficult-to-understand an­cient text was trying to convey. The modern reader shares neither language nor culture with the ancient writer. He can only interpret the translated words of the ancient writer in terms of his own personal experience within his modern culture and environment. To be able to understand any of the ancient text, the reader must share at least something with the ancient writer. They must share a common context through which the meaning encoded into words by the ancient writer is the same as that decoded from the translated words by the modern reader.

Radar Analogy

To illustrate this, another analogy is need­ed. A dolphin locates and targets its food by sonar — a type of radar that uses sound waves. This sonar not only tells it where its prey is located, but also gives it a detailed analytical picture of the size, type, shape and character of its prey. The key to its so­nar system is not so much in the principle of sound bouncing off a distant target, but is more to do with analysing in great detail the echo returning from the target. A large part of a dolphin's brain is dedicated to perform­ing this detailed analysis.

The principles of this natural system have been used by engineers in the design of very discern­ing over-the-horizon radar systems. They send an HF radio pulse which travels thousands of miles by bouncing back and forth off the ionosphere. When it hits a distant ship or air­craft, part of it is reflected back by the object. This echo bears the signature of the ship or aircraft from which it came.

The echo is received at the radar station where it is analysed in immense detail. Comparing the in­formation thus extracted from the echo with pre-stored information on all known ships and aircraft, the type and identity of the ship or aircraft is re­vealed.

The echo of the original signal returning from the target aircraft or ship, having had to travel thousands of miles bouncing between the ground (or sea) and the iono­sphere, is bound to be extremely weak by the time it finally gets back to the radar station. It is so weak that its strength is below the ambient noise level of the radio band. It cannot be heard at all through an ordinary receiver. It is completely swam­p­ed by the background hiss. Radio background noise is random in character. So if amongst the noise we find something that is not random, it is likely to be the echo we are looking for. To find non-randomness, we need a control sample of truly ran­dom noise with which to compare it.

Engineers are able to generate random noise locally, or take a control sample of the radio band's background noise from a frequency adjacent to that of the returning radar signal. It is then possible, by a means called digital signal processing, to filter out the echo signal from the random background noise. The echo's spectral signature is then compared with the known spectral signatures of actual ships and aircraft to reveal the identity of the target. One way of doing this is to pass the signal through electronic or software equivalents of the neural networks (illustration on the left) that the human brain employs to listen in to a con­versation taking place on another table in a noisy restaur­ant.

Cultural difference between ancient writer and modern reader, copying and transla­tion errors over the intervening centuries, misunderstandings of social, moral and economic context, unknown or forgotten figures of speech. These all introduce and compound a random noise which distorts, masks and buries the pure message ori­gi­nally encoded into the ancient text. It is therefore not an easy task to re-extract the original message from the ancient text. It takes a lot of dedication, effort and reasoned judgement.

Even then, you are unlikely ever to get a true picture of what an ancient text is saying. The modern over-the-horizon radar operator knows exactly what a MiG25 is, once the digital signal analysers have identified its echo to a reasonable degree of certainty. However, a reader may have no knowledge or experience of an object, process or phenomenon being referred to in an ancient text.

This is why the modern reader's understanding of individual words, sentences or statements in an ancient text is extremely prone to error. Until, that is, its com­patibility with the big picture given by the rest of the text and with direct physical observation has been substantiated.

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Parent Document | ©Mar 1997, Sep 2010 Robert John Morton