In the book, I make the point that here we have string theory and here we have twistor theory and we don't know if either one of them is the right approach to nature.

So what I'm saying is why don't we think about changing Schrodinger's equation at some level when masses become too big at the level that you might have to worry about Einstein's general relativity.

Well, gauge theory is very fundamental to our understanding of physical forces these days. But they are also dependent on a mathematical idea, which has been around for longer than gauge theory has.

Roger Penrose Quotes