Confirming (CF > 0)
Disconfirming (CF < 0)
Neutral (CF ≈ 0)
Propagation trace
Press Propagate to trace the formulas applied at each node.
Rule-based expert systems like MYCIN never assumed evidence was certain — instead every fact and rule carried a certainty factor (CF) on a −1..+1 scale, and the inference engine had exact formulas for combining them: minimum for AND, maximum for OR, and a special non-additive rule for merging two independent lines of evidence pointing at the same hypothesis. This 2D simulator renders the same diagnostic rule network as a flat node diagram — three uncertain evidence nodes feeding two rules that both conclude the same hypothesis H — and lets you set each evidence CF and each rule's own confidence, choose whether R1's antecedent is a conjunction or disjunction, and press Propagate to watch a pulse carry each CF value along the edges while the live readouts, node colors, and a step-by-step trace show exactly which real MYCIN combination formula fired at H.