PREDICTIONS – 10 Years Later - Santa Fe Institute

5. GOOD GUYS AND BAD GUYS COMPETE THE SAME WAY
tion. By far the biggest killers are diseases, particularly those that happen
to be prevalent at a given point in time. Today, cardiovascular
ailments claim the largest share, two-thirds of all deaths, with cancer
second at about half that number. A hundred years ago pneumonia and
tuberculosis were running ahead of cancer. It seems that diseases take
turns in claiming the lion’s share of all victims.
The detailed succession between front-running diseases will be
looked at more closely in Chapter Seven. In the meantime, I want to
invoke here a notion of competitive growth for the number of victims
claimed by a disease. The cumulative number of victims of the Red
Brigade was seen to follow S-curves, and there was some reason to consider
results of criminal activities as social ailments. Why not look at real
ailments that way?
Let us visualize diseases as species of microorganisms, the populations
of which compete for growth and survival. With the overall
number of potential victims being limited, the struggle will cause some
diseases to grow and others to fade, a situation similar to different species
populations growing to fill the same ecological niche. The extent of
the growth of a disease can be quantified by the number of victims it
claims. A relative rating is obtained if we express this number as a percentage
of all deaths. The percentage of victims claimed by the disease
best fitted for survival increases every year, while the unfit disease
claims a declining share.
We saw in Chapter One that with respect to deaths from car accidents,
society “feels” the risk and keeps tight control over the death rate.
Something analogous probably happens in regard to the overall deathrate
toll. Looking at the annual death rate per one thousand population
in the United States, we find that it was around seventeen at the turn of
the century and has been declining steadily to reach values around nine
in the late 1980s (see Figure 5.2). 3
Such a decline is what one expects from all the significant improvements
in medicine and living conditions achieved during the twentieth
century. Important deviations come from events like wars (for example,
1918) and even then, if spread over a number of years, as was the case
with World War II, the deviation washes out.
The important message from Figure 5.2 is the flattening of the steep
decline. The death rate decreases progressively more slowly and, during
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