Today while shopping for books at Borders I notice that “The God Equation” was shelved right next one of Feynman’s books. Of course, I had to correct this and moved the God book a few spaces to the right (I hope no librarians are reading this.) Of course the irony of this is that Feynman is the place where I first saw how you could right a single equation to represent a theory of everything (assuming that such a theory can be written down in terms of our algebraic notation…something which I feel shows quite a bit of hubris!) To do this, first notice that all equations can be written as A=0 where A is some probably nasty equation. A theory of everything, i.e. a set of equations describing all physics, will just be a collection of such equations, say A_1=0, A_2=0, … A_n=0: it’s important to make sure all of these equations are over real numbers, but this is easy to do. Now we can combine all of these equations into one by specifying
A_1^2+A_2^2+…+A_n^2=0
which is true iff all of the A_i=0! I’m not sure if Feynman was the first to pull this little slight of hand, but it was the first place I saw this trick.
Cool one trick and I first came to know of this through your blog 🙂