Fourth section: personal reflections
(1) Beware of beguiling words: one has to be careful not to be led down the garden path by nefarious doctrines such as Kantianism. So conceptual analysis has its limited place–but have it checked against empirically established results!
(2) The vacuum vs. zilch (cf Oliver and Smiley, Analysis): ‘zilch’ as a necessarily non-referring term, and its usefulness in philosophical discourse, and to avoid mystery mongering about the vacuum in QFT and LQG.
(3) Condensed matter approaches: challenges whether we have any grip on what the fundamental degrees of freedom are. Should we take it to be suspicious that some theories have remnants of less fundamental theories in them, such as the Ashtekar variables in LQG?
(4) Duality: Butterfield starts out from Belot’s appraisal that philosophers and physicists have different attitudes towards dual theories, where the former see two theories (because they reject verificationism) and the latter deny that (because they are moved by historical examples of dual pairs of theories who would then dissolve into a more general unified theories which was recognized as progress).