I revised this post after comments from Urska Demsar, Travis Gibson, Des Higham, Mason Porter, Max Schich, Jan Peter Schäfermeyer, Johan Ugander, and Jean-Gabriel Young. Thanks!

Our field is interdisciplinary, and many smart people have been thinking about similar things. No wonder things get reinvented and rediscovered many times. I don’t think science is a competition to get good ideas first. On the other hand, who was the first to come up with this or that is a perfect conversation starter across disciplines . . I know people rooting for their field like a sports team.

Here is a list of some first appearances/applications of some big ideas. I restrict myself to:

• The pre-Watts-Strogatz era.
• Ideas that are in active use today (sorry Euler).

But please take it all with a grain of salt and lemme know what I forgot.

The first published network illustration by Moreno, 1932.

Network positions