# General purpose technologies are technologies that are lower on the tree Technically the four for a General Purpose Technology are: 1. It is a single, recognizable generic technology 2. Initially has much scope for improvement but comes to be widely used across the economy 3. Has many different uses 4. Creates many spillover effects Each of these criteria are fuzzy. The tech tree model boils it down to a single equally fuzzy definition - “a node that unlocks large subtrees.” The concept of root node technologies is not new ([[There are scientific and technological problems that make other technology advances irrelevant by altering the environment]]) and the tree gives a way to unify them. Framing [[General purpose technologies]] in terms of the tech tree model enables you do useful analyses. These analyses include’ creating a ‘rank’ of GPTs, asserting what we would need to invent or discover for something to become a GPT, etc. [Web URL for this note](http://notes.benjaminreinhardt.com/General+purpose+technologies+are+technologies+that+are+lower+on+the+tree) [Comment on this note](http://via.hypothes.is/http://notes.benjaminreinhardt.com/General+purpose+technologies+are+technologies+that+are+lower+on+the+tree)