PHY.7:6 - Bias-Annotation

The examples make smooth classical stationarity easy to inspect. Quantum or probabilistic descriptions can connect an action to observations through a different rule; the fixed-history calculation here does not supply that rule. Use the principle and interpretation of the relevant physical theory.

Compact energy expressions can also hide how a constraint is maintained. The ideal rod, imposed pivot motion and massless endpoint spring each exclude physical detail. Restore that detail when reaction, compliance or a transient changes the requested consequence.