Whence the Effectiveness of Effective Field Theories?

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. The effectiveness of EFTs is explained by identifying the features-the scaling behaviour of the parameters-that lead to effectiveness. The explanation relies on distinguishing autonomy with respect to changes in micro states (autonomy(ms)), from autonomy with respect to changes in microlaws (autonomy(ml)), and relating these, respectively, to renormalizability and naturalness. It is claimed that the effectiveness of EFTs is a consequence of each theory's autonomy(ms) rather than its autonomy(ml).