Several times I've listened to Brian Greene talk about string theory and say that General Relativity is a macroscopic theory but Quantum Mechanics is a microscopic theory. Do you think it could be otherwise? I know that this is an accepted "dogma" that is often repeated by others but I wonder how far it really goes and maybe it is a line of thinking that leads one away from reconciling the two theories. How is it that microscopic particles must follow special relativity but not general relativity? What is mass? What is charge? Dr. Mendel Sachs makes some good points in his writings such as QUANTUM MECHANICS FROM GENERAL RELATIVITY that perhaps General Relativity can be incorporated in microscopic physics once the two theories are speaking the same mathematical language. There are some similar ideas in the writings of Lasenby and Doran and others working with Geometric Algebra. Whether this unified theory should be written in the language of spinors, quaternions, clifford algebra, geometric calculus or some other dialect, (all of these are related) I don't like the tower of Babel that currently exists in Physics. Several researchers have pointed out similarities of Yang Mills theory and General Relativity in a clifford algebra form. Could the idea that General Relativity is ONLY a MACROSCOPIC theory be a red herring?