"The first is that our brains are limited, and so we use crutches to supplement and extend our abilities...
The second observation is that the major prosthetic system we use is other people.
We set up what I call "Social Prosthetic Systems" (SPSs), in which we rely on others
to extend our reasoning abilities and to help us regulate and constructively employ our emotions.
A good marriage may arise in part because two people can serve as effective SPSs for each other", (can't prove, edge.org)