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No. 62: Mar-Apr 1989

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Measles epidemics: noisy or chaotic?

Incidence of measles in New York City
The incidence of measles in New York City, 1928-1964. Noise or chaos?
We should talk about chaos more. This subject threatens to undermine the popular notion that nature is fully deter ministic. We like to think that if we are given enough data that scientific laws will allow us to predict the future ac curately. But, unhappily, determinism stumbles when trying to cope with the weather, asteroid motion, the heart's electrical activity, and an increasing number of natural systems. Chaos lurks everywhere!

The growing split in scientific outlook is seen very clearly in the statistics of New York City measles epidemics before mass vaccinations. Take a look at the graph of recorded cases. The expected peaks occur each winter, but there is a strong tendency toward alternate mild and severe years.

Very nice mathematical models exist that purport to predict the progress of epidemics. They take into account such factors as the human contact rate, disease latency period, the existing immune population, etc. It is all very methodical, but it fails to account for the irregularities in actual data. Deterministic scientists claim that just by adding a little "noise" they could duplicate the observed curve. On the other hand, a very simple model that acknowledges the reality of chaos easily duplicates the measured data. Who is right? The determinists and chaosists (chaosians?) are now fighting it out.

(Pool, Robert; "Is It Chaos, or Is It Just Noise?" Science, 243:25, 1989.)

Comment. Much more of nature may be chaotic. Even evolution itself may be so. Are we merely a blip on a biological diversity curve, with a future that is unpredictable, regardless of what actions we take? Fortunately, lack of space prohibits the mention of Free Will!

Reference.See BHH2 in our catalog Biological Anomalies: Humans II for more on the periodicity of epidemics.

From Science Frontiers #62, MAR-APR 1989. 1989-2000 William R. Corliss

Science Frontiers Sourcebook Project Reviewed in:


  • "A sourcebook of unexplained phenomena is therefore a valuable addition to a collection of scientific literature. William R. Corliss has provided this in the past with his source books of scientific anomalies in several subjects, and now he has provided it for astronomy. He has done an excellent job of collecting and editing a large amount of material, taken in part from scientific journals and in part from scientific reporting in the popular or semi-scientific press." -- "The Mysterious Universe: A Handbook of Astronomical Anomalies", reviwed by Thomas Gold, Cornell University, in Icarus, vol.41, 1980

  • "An interesting, systematic presentation of unusual weather [..] This book is recommended for a general audience" --"Corliss, William R., Tornados, Dark Days, Anomalous Precipitation, and Related Weather Phenomena, Sourcebook Project, 1983.", revieweed in Choice, September 1983
  • "..the science is necessarily somewhat speculative, but Corliss's symthesis is based on reputable sources." -- "Corliss, William R. (Compiler). Lightning, Auroras, Nocturnal Lights, and Related Luminous Phenomena" reviwed by Joseph M. Moran, Univ. of Wisconsin in Science Books and Films, Sep/Oct 1983

  • "Before opening the book, I set certain standards that a volume which treads into dangerous grounds grounds like this must meet. The author scrupulously met, or even exceeded those standards. Each phenomenon is exhaustively documented, with references to scientific journals [..] and extensive quotations" -- "Book Review: The moon and planets: a catalog of astronomical anomalies", The Sourcebook Project, 1985., Corliss, W. R., Journal of the Royal Astronomical Society of Canada, Vol. 81, no. 1 (1987), p. 24., 02/1987