Physics Unravels the Truth Behind “The Enemy of My Enemy Is My Friend”

New study is first to use statistical physics to corroborate 1940s social balance theory.

Most people have heard the famous phrase “the enemy of my enemy is my friend.”

Now, Northwestern University researchers have used statistical physics to confirm the theory that underlies this famous axiom.

The study was published on May 3 in the journal Science Advances.

In the 1940s, Austrian psychologist Fritz Heider introduced social balance theory, which explains how humans innately strive to find harmony in their social circles. According to the theory, four rules — an enemy of an enemy is a friend, a friend of a friend is a friend, a friend of an enemy is an enemy and, finally, an enemy of a friend is an enemy — lead to balanced relationships.