I feel like it's more epistemological, but then I tend to think everything is. Perhaps it is another symptom of my biases, but I think it more likely that trying to build an AI will help clarify questions about ontology vs. epistemology than that anything in our present knowledge of ontology vs. epistemology will help in devising strategies for building an AI.
Cyc calls itself an ontology. Doesn't any AI need such an ontology to reason about the world?
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.