» Glossary » Watchmakers parable
There once were two watchmakers, named Hora and Tempus, who manufactured very fine watches. Both of them were highly regarded, and the phones in their workshops rang frequently – new customers were constantly calling them. However, Hora prospered while Tempus became poorer and poorer and finally lost his shop. What was the reason?
The watches the men made consisted of about 1.000 parts each. Tempus had so constructed his that if he had one party assembled and had to put it down -to answer the phone, say- it immediately fell into pieces and had to be reassembled from the elements. The better the customers liked his watches, the more they phone him, the more difficult it became for him to find enough uninterrupted time to finish a watch.
The watches that Hora made were no less complex than those of Tempus. But he had designed them so that he could put together subassemblies of about ten elements each. Ten of these subassemblies, again, could be put together into a larger subassembly; and a system of ten of the latter subassemblies constituted the whole watch. Hence, when Hora had to put down a partly assembled watch in order to answer the phone, he lost only a small part of his work, and he assembled his watches in only a fraction of the man-hours it took Tempus.— Herbert Simon, in The architecture of complexity (PDF), a paper published in 1962.
Herbert Simon uses this parable to explain how creating sub-systems and hierarchies is the basic tool to stabilize complex systems of any kind: social, biological, artificial, etc.