  I argue that the prediction of physical discreteness at the Planck scale in
loop gravity is a reasonable conclusion that derives from a sensible ensemble
of hypotheses, in spite of some contrary arguments considered in an interesting
recent paper by Dittrich and Thiemann. The counter-example presented by
Dittrich and Thiemann illustrates a pathology which does not seem to be present
in gravity. I also point out a common confusion between two distinct frameworks
for the interpretation of general-covariant quantum theory, and observe that
within one of these, the derivation of physical discreteness is immediate, and
not in contradiction with gauge invariance.
