The Law of the Hammer

Abraham Maslow in his book The Psychology of Science (1966) wrote “I suppose it is tempting, if the only tool you have is a hammer, to treat everything as if it were a nail”.

The law of the hammer is a cognitive bias that involves an over-reliance on a familiar tool. For example, when you learn a new economic concept you may apply it everywhere – which may result in failure to seek out other (potentially more efficient) alternatives.

The concept is attributed both to Maslow and to Abraham Kaplan although the hammer and nail line may not be original to either of them (or more information read here).

Charlie Munger in Poor Charlie’s Almanack (2005) [Link] wrote that one partial cure for the law of the hammer is multidisciplinarity. If a man has a vast set of skills over multiple disciplines, he, by definition, carries multiple tools and, therefore, will limit bad cognitive effects from man-with-a-hammer tendency.  In other words, single disciplines are too narrow a perspective regarding many phenomena. The world in which we live in exhibits a level of complexity that makes it impossible to understand the important phenomena that are affecting humans today from the perspective of any single incomplete system of thought.

In short, the mere knowledge from only one domain, is not enough. To be wise, you must develop a true curiosity to read different streams of literature and constantly learn new perspectives of the world.

To know more: read the introduction of The Nature and Method of Economic Sciences: Evidence, Causality, and Ends by R. F. Crespo (2020) [Link].


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