How do I describe the difference between a theory that is purely descriptive in nature, vs one that is predictive? I.e. the former gives a rigorous description of the physical state of a system, while the latter will give expressions for the laws which govern the evolution of the system (thus the former can in principle be deduced from the latter).
A simple example is the following pair:
A purely geometric description of the shape of islands on Earth (via fractal geometry or whatever you like), which is agnostic to the generating process of those islands which it is describing
A geological theory that predicts the manifestation of islands on Earth (from which the description offered in (1) could in principle be recovered). This works the other way around; the generating process is fully described, while the outcome is emergent from that process.
I'm not well-versed enough in philosophy to know how to eloquently describe this difference. It seems like it may be a contrast between ontology and (something)?