18. The method of claim 15 where establishing the one or more root nodes comprises: creating a probability table for each root node; each probability table having one or more predefined states; and each predefined state having associated with it a probability that the root node is in that state.
18. The method of claim 15 where establishing the one or more root nodes comprises: creating a probability table for each root node; each probability table having one or more predefined states; and each predefined state having associated with it a probability that the root node is in that state. 19. The method of claim 18 where creating the probability table for each root node comprises: completing the probability table based on quantitative observations of a natural system associated with the root node.