Wanhong HUANG
In one class of injury a set of factors, each individually incapable of destabilising the injured system, acts over a long period, reduces its capacity to recover from disturbance, and permits a later disturbance of ordinary magnitude to produce a severe outcome. Doctrine processes multi-causal injury with tolerable success and processes this class badly, and the reason is one of representation rather than of proof. The paper isolates one requirement, named datability: a change of state carrying legal significance must be assignable to a point in time. A dynamical presentation of a bistable system under slow forcing shows that the onset of criticality withholds what the requirement demands, for two reasons that hold of the system rather than of the observer, and six doctrinal operations fail together with it. Four consequences follow. Each factor is necessary and the conjunction of all of them remains insufficient, so the but-for test and the balance of probabilities come apart and the refinement requiring a sufficient set survives only by admitting a term attributable to nobody. The antecedent conduct and the terminal disturbance are excluded by different doctrines, and the threshold that decides which acts leave a record is the threshold that decides which acts carry significance, so the two exclusions are one filter counted twice. The predisposition on which reduction doctrines operate is a product of the conduct at issue, so those doctrines deduct the quantity that constitutes the wrong. Near a boundary of stability the outcome is completed by the amplification of the injured system, which doctrine reads through two settled figures that both discharge the defendants. The paper then separates two limitations of the classical apparatus. One concerns the resources available for recording and interpreting a history and would be relieved by their extension. The other concerns what a determinate contribution would require, namely closure of the set of variables bearing on the case, a declared class of admissible trajectories, and identifiability of the couplings, and it is unaffected by any capacity of the tribunal. Against the second the paper proposes findings of position, whose value is fixed by the record where the quantities are not, and observes that such findings are binary as a verdict is binary. It closes with the migration of the case to supervisory obligation, the price of that migration, and one route that dispenses with the representation of trajectories. Conditions of refutation are given throughout.