Some Remarks about Quantum Gravity

Gravitation is the oldest of the fundamental interactions known to us. It finds an extraordinarily beautiful and simple formulation in Einstein’s General Relativitiy, which embodies the equivalence principle by requiring the invariance of the theory under general reparametrization of the co-ordinates xμ → x′μ = fμ(x). Experiments confirm the predictions of the classical theory in the macroscopic, large distance, domain.