From D.McCullogh. As I understand it, Weyl's original gauge theory allowed for the possibility that length scale can change from point to point. Has there been any modern work on Weyl's theory? In particular, is it possible to develop a quantum version? Another question: is it possible that something interesting (perhaps GR) could result from Weyl's theory through spontaneous symmetry breaking? What's interesting about Weyl's theory is that classically (ignoring quantum mechanics) there is no good reason for physics to have a preferred length scale. What sets the length scale for material objects seems to be the Bohr radius, r_b = hbar^2/(m e^2) So that makes me think that perhaps quantum corrections to Weyl's theory might break his gauge symmetry. END Could be on to something here D. Especially ignoring quantum mechanics! What do youse all think?