The Bayes Net and Causal Inference

The Bayes net is a computational device that allows you to solve certain kinds of probability problems. In this case what's the probability that there actually is a burglar burglary if john calls and mary doesn't call okay? And then i kind of know based on that whether this is i need to worry or not okay so it's very cool what you can do with thisThis is another thing that i had to study in my artificial intelligence class in in school now what is base rule and how does it work?"