He gave some examples. So, for instance, the Church used to say death penalty was permissible, but now the "Church" says it's not.
So, by "progress", he means a contradiction of the Church's previous teaching, not an expansion upon or elaboration of it, or a new application to particular circuмstances.
This is in fact the very definition of Modernism. And then he has the temerity to cite St. Vincent of Lerins as a defender of Modernism.