This article is the fifth of this weekly series called Latticework of Mental Models, which will be authored by my friend and partner in writing the Value Investing Almanack, Anshul Khare. Anshul will write on various mental models – big ideas from various disciplines – which can help you think more rationally while analyzing businesses and making your stock investment decisions.

Between the years 1324 to 1351, Delhi was ruled by an emperor named Mohammad-bin-Tughluq from the Tughluq dynasty. He had a scholastic background and spoke multiple languages. In spite of good intentions, some of the policies that he enforced during his rule backfired which made him infamous as an eccentric ruler. One such failed idea was about an experiment that he did with the local currency.
Tughluq noticed that India had very few silver coins and a comparatively larger number of bronze and copper coins. He decided to promote bronze or copper coins by passing a royal order that bronze and copper coins are to be accorded the same value (i.e., same purchasing power) as silver coins. In other words, he wanted the markets to mentally consider bronze and copper as silver itself so that 1 gram coin of bronze can buy the same goods as 1 gram of silver. It looked like a neat idea however the emperor failed to consider the law of unintended consequences.
[Read more…] about Latticework of Mental Models: Gresham’s Law