Three Bodies

In Poul Anderson's Twilight World, Roderick Wayne says that physicists can easily solve the two-body problem in astronomy but not the three-body problem. If the mass, velocity and mutual distance of two bodies at a given time are known, then the laws of motion and gravitation make it possible to calculate the positions of those same bodies at any other time. However, even one more interacting body makes the motions so complex that they become unpredictable.

This mirrors a reflection that I have made about interpersonal interactions. Two people are one interaction, AB, whereas adding one more person adds three more interactions: BC, CA and ABC. Further, A's perceptions of BC affect A's responses to B and to C and so on. (I was in a domestic situation where this became apparent.)

So how many physical interactions have psychological counterparts? And I cannot possibly ponder such a puzzling poser at this time of night.

Tomorrow: Lytham 1940s Festival.