Causation in the Law: Philosophy, Doctrine and Practice
Forthcoming in The Common Core of European Private Law: Causation (Marta Infantino and Eleni Zervogianni eds. Cambridge Univ. Press, 2016)
34 Pages Posted: 15 Mar 2016
Date Written: March 12, 2016
Causation plays an essential role in attributions of legal responsibility. However, considerable confusion has been generated by the use of causal language to refer not merely to causation in its basic (actual/factual/natural) sense, which refers to the operation of the laws of nature, but also to the quite different normative issue of appropriate legal responsibility. To reduce such confusion, we argue that causal language should be used in the law to refer solely to causation in its basic sense.
While it is often said that the law need not and should not concern itself with philosophical analyses of causation, we argue that a failure to take into account rigorous philosophical analysis of causation in its basic sense and to distinguish it from the normative issue of legal responsibility has been a source of major confusion in the law. After summarizing the relevant modern philosophical analyses of causation, we criticize the strong necessity (sine qua non, 'but for') criterion in its counterfactual form and as a supposed exclusive (factual or counterfactual) test of causation, as well as primitivist "we know it when we see it" accounts. We argue, instead, for the need to employ the comprehensive, factual, weak-necessity/strong-sufficiency criterion, which is based on the "covering law" account elaborated by John Stuart Mill and which has been developed in the modern legal literature as the "NESS" (necessary element of a sufficient set) criterion.
Drawing again on the covering law account, we explain the importance of understanding the required standards of persuasion for proving causation (or any other fact) as generally requiring the generation of a warranted belief rather than a mere statistical probability, and we note the confusion and paradoxes that result from some courts' employing the statistical probability interpretation in situations in which there is inherent uncertainty regarding causation, rather than acknowledging the inherent uncertainty and explicitly addressing the normative responsibility issue.
While, pending further discussion, we disagree on some issues, such disagreement should not detract from our agreement on the most fundamental issues, including the NESS (weak necessity/strong sufficiency) covering law account of causation, the rejection of counterfactual possible worlds analysis, the inclusion of omissions and other absences as causes, the importance of focusing the causal analysis on the properties of events and states of affairs rather than events and states of affairs as a whole, and, relatedly, the importance of focusing the causal analysis for purposes of legal responsibility on the causal connection between the wrongful aspects of the defendant's conduct and the relevant legal injury. Whatever disagreements we may have now or in the future pale in comparison to the defects of any alternative analysis of causation, especially the strong necessity (sine qua non, "but for") analysis as an exclusive and/or counterfactual analysis or any account that purports not to rely on causal laws.
Keywords: causation, omissions, negative conditions, events, properties, strong necesssity, weak necessity, strong sufficiency, sine qua non, but for, counterfactual, NESS, primitivist singularism, proof, standards of persuasion, belief, statistical probability
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