  Recently there has been significant interest in using causal modelling
techniques to understand the structure of physical theories. However, the
notion of `causation' is limiting - insisting that a physical theory must
involve causal structure already places significant constraints on the form
that theory may take. Thus in this paper, we aim to set out a more general
structural framework. We argue that any quantitative physical theory can be
represented in the form of a generative program, i.e. a list of instructions
showing how to generate the empirical data; the information-processing
structure associated with this program can be represented by a directed acyclic
graph (DAG). We suggest that these graphs can be interpreted as encoding
relations of `ontological priority,' and that ontological priority is a
suitable generalisation of causation which applies even to theories that don't
have a natural causal structure. We discuss some applications of our framework
to philosophical questions about realism, operationalism, free will, locality
and fine-tuning.
