I assert that the idea of "authoritative data" for a lot of hypothetical questions people would explore will itself be a hindrance. That is, for most hypotheti

I assert that the idea of "authoritative data" for a lot of hypothetical questions people would explore will itself be a hindrance. That is, for most hypothetical scenarios, you explicitly want modeled data. Ideally, you would know the parameters used in generating the data, but the entire point of many hypotheticals is you are projecting into an area where you don't have data. Or building a counterfactual world and predicting what it would have changed. Similarly, "invariant preserving operations" is not necessarily what you want, either? You want to know what other parameters you would need to adjust to keep some conditions. But you want to be able to edit anything free form and then interact with it to get back to a "solved" state. That is to say, when interacting with a system, you explicitly want to allow bad or incomplete states. (This is, ultimately, what kills many "code as an AST" ideas.) FreeCAD has a good example to consider on this. When drafting, you can pretty much freeform draw a part. But if you want to finish the session, you have to fully specify all parameters. This doesn't mean you can't add to the drawing while it is unsolved. It does mean that you can't take it to the next phase without fully solving. This can be difficult if you don't have training material on how to use an application. And while it can be frustrating that you can save something in a state where you can't click "next," it is also frustrating to have a system where you can't save what you currently have to send to someone else to look at.