![cover image](https://wikiwandv2-19431.kxcdn.com/_next/image?url=https://upload.wikimedia.org/wikipedia/commons/thumb/6/67/HK_%25E9%2596%258B%25E7%25BD%2590%25E9%25A0%25AD%25E5%2588%2580_Fork_sharp_can_opener_October_2018_IX2_02.jpg/640px-HK_%25E9%2596%258B%25E7%25BD%2590%25E9%25A0%25AD%25E5%2588%2580_Fork_sharp_can_opener_October_2018_IX2_02.jpg&w=640&q=50)
Assume a can opener
Mocking catchphrase / From Wikipedia, the free encyclopedia
"Assume a can opener" is a catchphrase used to mock economists and other theorists who base their conclusions on unjustified or oversimplified assumptions.[1][2]
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/6/67/HK_%E9%96%8B%E7%BD%90%E9%A0%AD%E5%88%80_Fork_sharp_can_opener_October_2018_IX2_02.jpg/640px-HK_%E9%96%8B%E7%BD%90%E9%A0%AD%E5%88%80_Fork_sharp_can_opener_October_2018_IX2_02.jpg)
The phrase derives from a joke which dates to at least 1970 and possibly originated with British economists.[3] The first book mentioning it is likely Economics as a Science (1970) by Kenneth E. Boulding:[4]
There is a story that has been going around about a physicist, a chemist, and an economist who were stranded on a desert island with no implements and a can of food. The physicist and the chemist each devised an ingenious mechanism for getting the can open; the economist merely said, "Assume we have a can opener"!
The phrase was popularized in a 1981 book and has become sufficiently well known that many writers on economic topics use it as a catchphrase without further explanation.[5][6]