MMP.19:10 - Architectural Rationale

The hard step is often the relation between calculations, rather than each calculation separately. Ordinary conditioning recovers case information; mechanism replacement constructs an alternative; the common input or response-type law connects them. Maintaining that relation permits a joint question and exposes assumptions invisible in separate marginal fits.

The same construction supports historical explanation, probabilities of benefit and nested pathways. Their targets remain distinct. In particular, a decision based on realized outcomes can use less structure than a question about how those outcomes would differ for the same unit.