The successes of the differential equation paradigm were impressive and extensive. Many problems, including basic and important ones, led to equations that could be solved. A process of self-selection set in, whereby equations that could not be solved were automatically of less interest than those that could.
Ian Stewart
Source: Does God Play Dice? The Mathematics of Chaos. Blackwell, Cambridge, MA, 1989, p. 39.
Contributed by: Zaady