Trolleys and Transplants: Derailing the Distinction Between Doing and Allowing


  • Emma Duncan University of California, San Diego, USA



Trolley Problem, Doing and Allowing, Judith Jarvis Thomson, Killing, Allowing to Die Punishment, Rebellion


Two key elements in Judith Jarvis Thomson’s most recent response to the famed Trolley Problem produce a tension that threatens to undermine her account. First, in a reversal of part of her 1985 position, Thomson now argues that a bystander is not permitted to divert a threat. Second, her use of the Doctrine of Doing and Allowing (DDA) to explain intuitions about the permissibility of threat diversion conflicts with her constraint of an agent’s available options to the present tense, which is designed to prevent past bad acts from justifying bad acts in the present. I contend that the conflict between DDA and the tense constraint creates an inconsistency in Thomson’s current position and supports the conclusion that no one, including the trolley driver, is permitted to turn the trolley. In order to resolve this conflict, Thomson must either abandon one of the core features of her explanation or reject a fundamental intuition driving the Trolley Problem, that the driver may divert the trolley to save lives.


Foot, Philippa. ‘The Problem of Abortion and the Doctrine of Double Effect’, in Philippa Foot, Virtues and Vices and Other Essays in Moral Philosophy, Berkeley: University of California Press, 1978, pp. 19-32.

Friedman, A. W. Minimizing Harm: Three Problems in Moral Theory. Massachusetts Institute of Technology (PhD diss.), 2002.

Frowe, Helen. ‘Equating Innocent Threats and Bystanders’, Journal of Applied Philosophy, 25:4 (2008), pp. 277-290. doi: 10.1111/j.1468-5930.2008.00406.x

Hanna, Jason. ‘Doing, Allowing, and the Moral Relevance of the Past’, Journal of Moral Philosophy, (2014), online.

Thomson, Judith Jarvis. ‘Killing, Letting Die, and The Trolley Problem’, The Monist, 59:2 (1976), pp. 204-217. doi: 10.5840/monist197659224

Thomson, Judith Jarvis. ‘The Trolley Problem’, The Yale Law Journal, 94:6 (1985), pp. 1395-1415. doi: 10.2307/796133

Thomson, Judith Jarvis. ‘Self-Defense’, Philosophy and Public Affairs, 20:4 (1991), pp. 283-310.

Thomson, Judith Jarvis. ‘Turning the Trolley’, Philosophy & Public Affairs, 36:4 (2008), pp. 359-374. doi: 10.1111/j.1088-4963.2008.00144.x




How to Cite

Duncan, E. (2015) “Trolleys and Transplants: Derailing the Distinction Between Doing and Allowing”, De Ethica, 2(2), pp. 9–18. doi: 10.3384/de-ethica.2001-8819.15229.