I think it's worth noting that, in addition to boundaries where one might expect a single intuitive boundary to exist (like the above example of identifying human agents or consenting to tumor excision), there might be types of boundaries where one of multiple potential boundaries must be chosen via subjective preference (for instance, I think one could use boundaries to formalize property rights or the sovereignty of communities or municipalities, but in practice those are both initially constrained by culture, local laws, and/or customs, and therefore va...
Ah, you might have caught right when we were updating links to davidad's program and re-uploading. It works for me now on Firefox, but please let me know if it doesn't work for you and we'll debug more.