I'm working on a book about 17th century and early 18th economics, 
beginning with William Petty. After describing his wild personal 
life, I'm trying to make the connection between Petty's emergence and 
the global climate at the time. Please tell me if this is too far-fetched.

Mother Nature may have smiled upon William Petty, whose maturity 
coincided with a short, but welcome break in the Little Ice Age. 
Shortly before Petty's death in 1687, the cold weather returned. For 
example, the winter of 1683-4 was particularly harsh (Lamb 1982, p. 223).

Today, when the threat of global warming looms large, people might be 
more sensitive to the profound effects of the weather. In earlier 
periods of cold weather created equally harmful results. One 
long-term study of the effects of weather over the centuries 
concluded: "cooling impeded agricultural production, which brought 
about a series of serious social problems, including price inflation, 
then successively war outbreak, famine, and population decline 
successively. The findings suggest that worldwide and synchronistic 
war-peace, population, and price cycles in recent centuries have been 
driven mainly by long-term climate change" (Zhang et al. 2007, p. 19215).

David Hackett Fischer's _The Great Wave: Price Revolutions and the 
Rhythm of History_ paints the stark picture of the times of Petty's youth:

Famine, pestilence, and economic depression were accompanied by war. 
During the entire century from 1551 to 1650, peace prevailed 
throughout the continent only in a single year 1610. These conflicts 
were remarkable not only for their frequency but also their ferocity.

During the early seventeenth century, the armies of Europe reached 
their largest size since the Roman era. Their upkeep imposed heavy 
costs at the same time that public revenues were reduced by the 
combined effect of famine, pestilence, war, depression, regressive 
taxation and monetary inflation. They also were put to use in most of 
Europe. [Fisher 1996, pp. 96-97]

Fisher went on to add: "The greatest works of literature, painting, 
philosophy and theology in this era commonly expressed a mood of 
increasing pessimism and despair" (Fisher 1996, p. 100). During the 
second half of the Seventeenth Century, conditions were improving 
grain prices tended to fall (Fisher 1995, p. 105).

None of this is meant to suggest that the world suddenly became a 
comfortable place of peace and prosperity. The winter of 1683-4 was 
particularly cold. In addition, Petty's own work with the Royal 
Society was closely associated with preparing for military 
adventures. Some of his later writings suggested that the prospects 
for war with France were favorable. And finally, an optimistic belief 
in progress was not unknown during the cold period. Samuel Hartlib, 
Petty's own promoter was a case in point.

Nonetheless, the optimistic swagger of Petty's proposals fell on more 
fertile ground as future prospects were looking better. More broadly, 
economic thinking tends to follow one of two paths. First, some give 
an ideological justification of the status quo, arguing that what is 
happens to be the optimal arrangement for now and for the future. 
Others offer proposals for improvement. At times, such as the warming 
mid-seventeenth century, when new possibilities seem to be opening, 
such proposals are more likely to fall on fertile ground.

For example, even though Hartlib's musings about information might 
seem quite modern in light of the Internet, he never exercised much 
influence. Petty, who also had his share of far-fetched ideas, was 
generally recognized as a genius, even by many who disagreed with him.


Michael Perelman