Fig. 1: The three-level framework (taken from Goertz (2020, p. 28)).
From: Experimenting with a strong dual necessity approach to social progress
The basic level here is the concept of Social Progress; SL1 is the subjective component; SL2 is the objective component (each of them is constructed by various DILs). With a strong Dual Necessity, the structure of the secondary level is the AND structure (the question mark in red).
