I can imagine that if we were able isolate a region from the Higgs field (much as we use Faraday cages, i.e. metal boxes, to protect circuits from electromagnetic interferences), we can turn all the particles inside the region massless.
I know he was just theorising, but if it is possible to isolate regions of space from the Higgs field, thus reducing the mass of the contents, then wouldn't that explain where the missing dark matter in the universe is? Could it simply be located in areas of space where the Higgs field is non-existent or reduced?
"I prefer rogues to imbeciles, because they sometimes take a rest." -- Alexandre Dumas (fils)