The new math - so simple only a child can do it. Tom Lehrer
Our involvement with David Hestenes began ten years ago, when he attended a Maximum Entropy conference in Laramie. It is a testimony to David's range of interests that one of us (SFG) was able to interact with him at conferences for the next six years, without becoming aware of his interests outside the fields of MaxEnt, neural research and the teaching of physics. He apparently knew that astronomers would not be interested in geometric algebra. Our infection with his ideas in this area started in 1988, when another of us (ANL) stumbled across David's book `Space-Time Algebra', and became deeply impressed. In that summer, our annual MaxEnt conference was in Cambridge, and contact was finally made. Even then, two more months passed before our group reached the critical mass of having two people in the same department, as a result of SFG's reading of David's excellent summary `A Unified Language for Mathematics and Physics'. Anyone who is involved with Bayesian probability or MaxEnt is accustomed to the polemical style of writing, but his 6-page introduction on the deficiencies of our mathematics is strong stuff. In summary, David said that physicists had not learned properly how to multiply vectors and, as a result of attempts to overcome this, had evolved a variety of mathematical systems and notations that has come to resemble Babel. Four years on, having studied his work in more detail, we believe that he wrote no less than the truth and that, as a result of learning how to multiply vectors together, we can all gain a great increase in our mathematical facility and understanding.