Injury, Probability, and Mamma Mia!
In Mamma Mia!, Sophie invites three men she has never met to her wedding. She knows that one of these three men is her father, but she does not know which one. The movie is notable for a number of reasons. It is notable, first, because it is the second movie this summer (after Sex and the City) apparently made for, and featuring, women over 40. It is also notable for its relationship to tort law (I mean, aside from the obvious link related to Pierce Brosnan’s singing). The explanation is after the jump (to avoid revealing a key plot point, to the extent there is a plot). (Translation: there is a spoiler after the jump–though really, if you are going to Mamma Mia! for the gripping story line, you have much larger problems.)
Sophie’s mother admits, at the end of the movie, that she simply does not know which man is Sophie’s father. (Apparently in the parallel universe in which people spontaneously burst into fully-orchestrated ABBA songs, DNA testing does not exist.) “Well, one-third of a child is more than I ever thought I would have,” one of the men says. Each of the other men then indicates that he too now views himself as having one-third of a child. (There may be a link to property law here, though I am just going to assume that each has a one-third undivided interest in the whole–the other alternatives are simply too disturbing to consider.)
Anyway, the three men’s immediate conclusion that each was the father of one-third of the child reminded me, of course, of Summers v. Tice. This was the case in which Tice, Summers, and Simonson went hunting, and Summers was shot in the eye (among other places). There was no proof as to which of Tice and Simonson had fired that shot, so the court held that both men were liable, and they should apportion the damages between them, presenting, if they could, any proof that they were not the responsible party.
But that didn’t seem quite right as a way to understand Mamma Mia!–there would be no reason for each man to automatically assume one-third of Sophie. Was each man really equally likely to be her father? Moreover, the men were certainly not in a better position than Sophie’s mother to determine which of them was the father. So then I started thinking that the Mamma Mia! situation might be more like market share liability, where liability is apportioned based on the share each party has of the market. So, for example, the mother of plaintiff in Sindell v. Abbott Laboratories (sorry for the edited .doc version; can’t find a full, free html version) had taken DES, which had caused her child to develop cancer. The plaintiff did not know which company had manufactured the specific DES that her mother had taken, and the court held that rather than spreading the liability equally among the manufacturers who were the defendants, each defendant was liable for the proportion of the judgment represented by its share of the market. This, the court reasoned, would approximate each manufacturer’s share of the liability.
How, then, I wondered, should the market share, so to speak, be apportioned among the three men? I began to muse on this for a moment; then, as I experienced dawning horror at the train of thought this was triggering (Pierce Brosnan!), I reminded myself, with some relief, that I am a tax professor, not a torts professor, and that this was Mamma Mia!, after all, so I stopped.