Krugman: Mapmaking, modeling and the evolution of ignorance

[From Matti Kolu (2013.11.10.2015 CET)]

"THE EVOLUTION OF IGNORANCE

A friend of mine who combines a professional interest in Africa with a hobby
of collecting antique maps has written a fascinating paper called "The
evolution of European ignorance about Africa." The paper describes how
European maps of the African continent evolved from the 15th to the 19th
centuries.

You might have supposed that the process would have been more or less
linear: as European knowledge of the continent advanced, the maps would have
shown both increasing accuracy and increasing levels of detail. But that's
not what happened. In the 15th century, maps of Africa were, of course,
quite inaccurate about distances, coastlines, and so on. They did, however,
contain quite a lot of information about the interior, based essentially on
second- or third-hand travellers' reports. Thus the maps showed Timbuktu,
the River Niger, and so forth. Admittedly, they also contained quite a lot
of untrue information, like regions inhabited by men with their mouths in
their stomachs. Still, in the early 15th century Africa on maps was a filled
space.

Over time, the art of mapmaking and the quality of information used to make
maps got steadily better. The coastline of Africa was first explored, then
plotted with growing accuracy, and by the 18th century that coastline was
shown in a manner essentially indistinguishable from that of modern maps.
Cities and peoples along the coast were also shown with great fidelity.

On the other hand, the interior emptied out. The weird mythical creatures
were gone, but so were the real cities and rivers. In a way, Europeans had
become more ignorant about Africa than they had been before.

It should be obvious what happened: the improvement in the art of mapmaking
raised the standard for what was considered valid data. Second-hand reports
of the form "six days south of the end of the desert you encounter a vast
river flowing from east to west" were no longer something you would use to
draw your map. Only features of the landscape that had been visited by
reliable informants equipped with sextants and compasses now qualified. And
so the crowded if confused continental interior of the old maps became
"darkest Africa", an empty space.

Of course, by the end of the 19th century darkest Africa had been explored,
and mapped accurately. In the end, the rigor of modern cartography led to
infinitely better maps. But there was an extended period in which improved
technique actually led to some loss in knowledge.

Between the 1940s and the 1970s something similar happened to economics. A
rise in the standards of rigor and logic led to a much improved level of
understanding of some things, but also led for a time to an unwillingness to
confront those areas the new technical rigor could not yet reach. Areas of
inquiry that had been filled in, however imperfectly, became blanks. Only
gradually, over an extended period, did these dark regions get re-explored."

[...]

"Why is our attitude so different when we come to social science? There are
some discreditable reasons: like Victorians offended by the suggestion that
they were descended from apes, some humanists imagine that their dignity is
threatened when human society is represented as the moral equivalent of a
dish on a turntable. Also, the most vociferous critics of economic models
are often politically motivated. They have very strong ideas about what they
want to believe; their convictions are essentially driven by values rather
than analysis, but when an analysis threatens those beliefs they prefer to
attack its assumptions rather than examine the basis for their own beliefs.

Still, there are highly intelligent and objective thinkers who are repelled
by simplistic models for a much better reason: they are very aware that the
act of building a model involves loss as well as gain. Africa isn't empty,
but the act of making accurate maps can get you into the habit of imagining
that it is. Model-building, especially in its early stages, involves the
evolution of ignorance as well as knowledge; and someone with powerful
intuition, with a deep sense of the complexities of reality, may well feel
that from his point of view more is lost than is gained. It is in this
honorable camp that I would put Albert Hirschman and his rejection of
mainstream economics."

-- Krugman,THE FALL AND RISE OF DEVELOPMENT ECONOMICS,
http://web.mit.edu/krugman/www/dishpan.html

Matti