 
Summary: 354 PERFECTLY REASONABLE DEVIATIONS FROM THE BEATEN TRACK
RICHARD C. HENRY TO RICHARD P. FEYNMAN, DECEMBER 2, 1982
Dear Professor Feynman:
I am an astronomer located in a Physics department, and experiencing ever increasing joy at
teaching physics (as opposed to astronomy). Some of that joy expressed itself in an article for
"The Physics Teacher" (copy enclosed); if you have time to read it and have any corrective
comments, I would be very glad.
The reason I write to you is that I vacationed in Florida over Thanksgiving, and for light
reading had Eddington's The Mathematical Theory of Relativity. He puts words to equations
extraordinarily well; almost as well as the Feynman Lectures. But even he is not able to verbally
discuss, and does not try to mathematically discuss, a fascinating question: what would it be
"like" to inhabit a world with 3 space dimensions and two time dimensions (see enclosure from
Eddington's book)?
This was a question I asked myself in grad school, and that I once asked Charlie Misner at a
party; I've never gotten an answer. At first I asked myself whether there might not be two time
dimensions, and that's where the quantummechanical funny business comes from! More lately
I think the answer might be much duller: identical clocks running at different rates, and
changing rates if they collide.
If the answer is interesting, would it make a good article (for you to write!) for the Physics
Teacher? Just a suggestion!
