I do not know what you mean by a Bayesian belief network about an argument.
What I called a BBN (it may be a generalization of the standard concept) is a belief system schema constructed to be capable of representing your reasoning and my reasoning. Nodes are propositions and arrows are inferential steps. The schema must contain a node for every proposition that I use and every proposition that you use, and similarly must contain an arrow for every inferential step appearing in the argument of either person. Once we have that diagram, our two arguments may then be represented as each flowing through a portion of it. We arrive at opposite truth values for a common terminal proposition, so the arguments are in contradiction. To resolve the contradiction or at least identify its cause, we move upstream and try to identify where initial conditions differ.
This process will most likely require one to state opinions regarding certain implicit premises, used by the other person, which did not even play a role in one’s own argument, as well as to express differing opinions about the arrows, i.e., about the implications of one proposition for the truth of another. One of us may regard the truth of B as independent of the truth of A, whereas the other would say that if A is true, then B is definitely false—or probably false. It is merely a formal process meant to guarantee that the sources of disagreement are mutually understood, something which should happen anyway if the disagreement has developed in a lucid and orderly fashion.
What I called a BBN (it may be a generalization of the standard concept) is a belief system schema constructed to be capable of representing your reasoning and my reasoning. Nodes are propositions and arrows are inferential steps. The schema must contain a node for every proposition that I use and every proposition that you use, and similarly must contain an arrow for every inferential step appearing in the argument of either person. Once we have that diagram, our two arguments may then be represented as each flowing through a portion of it. We arrive at opposite truth values for a common terminal proposition, so the arguments are in contradiction. To resolve the contradiction or at least identify its cause, we move upstream and try to identify where initial conditions differ.
This process will most likely require one to state opinions regarding certain implicit premises, used by the other person, which did not even play a role in one’s own argument, as well as to express differing opinions about the arrows, i.e., about the implications of one proposition for the truth of another. One of us may regard the truth of B as independent of the truth of A, whereas the other would say that if A is true, then B is definitely false—or probably false. It is merely a formal process meant to guarantee that the sources of disagreement are mutually understood, something which should happen anyway if the disagreement has developed in a lucid and orderly fashion.