OP here. If you haven't seen this paper before, take a look at Tables I and II, which show two simple, discrete, probability distributions for three variables,

OP here. If you haven't seen this paper before, take a look at Tables I and II, which show two simple, discrete, probability distributions for three variables, each of which consists of two bits (i.e., each variable can take four possible values, 00, 01, 10, and 11). In each distribution, the three variables depend on each other. The distributions are different, but if you take a look at figures 1, 2, and 3, you will see that their Shannon Entropy diagrams are the same, and that a directed acyclic graph cannot represent either distribution. Let me repeat that: today (1) there is no consistent way to measure the information of the three variables in these toy distributions, and (2) no Bayesian model can measure their dependencies. In short, probability theory cannot cope with these toy distributions. Wow.