A method is provided for fusing a plurality of self-contained diagnostics for generating a combined state of belief for a monitored system. A plurality of predetermined diagnostic states of self-contained diagnostic routines is executed. Each self-contained routine generates a respective state of belief result for the monitored system. Respective belief vectors are formulated as a function of belief results. A state space is provided that includes a plurality of sub-state spaces. Each of the sub-state spaces is representative of the predetermined diagnostic states of the monitored system. Belief vectors are assigned to the sub-state spaces of the state space. Belief vectors relating to each sub-state space are fused. A combined belief value is determined for each fused sub-state space. The sub-state space having the highest combined belief value is indicated in response to the determined probabilities as the actual diagnostic state of the monitored system.