Philosophy of Physics Seminar (Thursday - Week 7, HT19)

Effective Quantum Field Theories (EFTs) are effective insofar as they apply within a prescribed range of length-scales, but within that range they predict and describe with extremely high accuracy and precision. I will argue that the effectiveness of EFTs is best explained in terms of the scaling behaviour of the parameters. The explanation relies on distinguishing autonomy with respect to changes in microstates (autonomy_ms), from autonomy with respect to changes in microlaws (autonomy_ml), and relating these, respectively, to renormalisability and naturalness. It is claimed, pace Williams (2016), that the effectiveness of EFTs is a consequence of each theory's renormalisability rather than its naturalness. This serves to undermine an important argument in favour of the view that only natural theories are kosher. It has been claimed in a number of recent papers that low-energy EFTs are emergent from their high-energy counterparts, see e.g. Bain (2013) and Butterfield (2014). Building on the foregoing analysis, I will argue that the emergence of EFTs may be understood in terms of the framework developed in Franklin and Knox (2018). 

There will be a dinner following the seminar, open to all (at your own expense). Please email james.read@philosophy.ox.ac.uk by Wednesday morning before the seminar if you would like to attend.