A New and Improved Doctrine of Double Effect: Not Just for Trolleys

76 Pages Posted: 11 Feb 2022 Last revised: 4 Apr 2022

See all articles by Sherry F. Colb

Sherry F. Colb

Cornell University - Law School

Date Written: February 10, 2022


In its standard formulation, the Doctrine of Double Effect (DDE) permits an action that has foreseeable harmful, even dire, collateral consequences, so long as the actor merely foresees but does not intend them and the harms are considered proportional to the benefit. Yet DDE’s critics question the moral distinction between intending a bad outcome, on one hand, and acting in exactly the same way under the same circumstances but merely knowing that the actions will result in the bad outcome, on the other. After all, except in a few narrow circumstances, criminal law in the United States treats purpose and knowledge as equally culpable mental states that each amount to “intent.”

This Article reinterprets and reconstructs DDE to avoid this critique. Properly reimagined, DDE does not depend on an actor’s subjective goal. Instead, it allows an action if one can plausibly identify a permissible goal to explain that action and any resulting harm is proportionate to that permissible goal. However, if the only plausible way to understand a particular action is as the product of an impermissible purpose, then the action is impermissible, and there is then no need to inquire into proportionality. Thus reconceived, DDE helps make sense of how the law resolves problems in a wide range of contexts, including jury nullification, disparate impact race discrimination, and the admissibility of evidence that proves too much. With the notable exception of most prohibitions against intentional discrimination—which control the special context of at-will employment and other at-will settings DDE as reconstructed proves to be a powerful instrument for answering challenging legal questions.

Keywords: Doctrine of Double Effect, DDE, criminal law, United States, purpose, knowledge, purpose and knowledge, mental state, subjective goal, plausibly, permissible goal, jury nullification, disparate impact race discrimination, admissibility of evidence, intentional discrimination, at-will employment

Suggested Citation

Colb, Sherry F., A New and Improved Doctrine of Double Effect: Not Just for Trolleys (February 10, 2022). Connecticut Law Review, Forthcoming, Cornell Legal Studies Research Paper No. 22-08, Available at SSRN: https://ssrn.com/abstract=4031866 or http://dx.doi.org/10.2139/ssrn.4031866

Sherry F. Colb (Contact Author)

Cornell University - Law School ( email )

Myron Taylor Hall
Ithaca, NY 14853
United States

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