To understand why philosophers invariably reject the Simple Theory of Joint Action in favour of bolder alternatives, consider objections to it. The objections aim to show that the Simple Theory cannot distinguish between all the contrast cases that an account of shared agency must distinguish.
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Our aim in this section is to find grounds for rejecting the Simple Theory of Joint Action.
Michael Bratman offers a counterexample to something related to the Simple Theory of Joint Action. Suppose that you and I each intend that we, you and I, go to New York together. But your plan is to point a gun at me and bundle me into the trunk (or boot) of your car. Then you intend that we go to New York together, but in a way that doesn’t depend on my intentions. As you see things, I’m going to New York with you whether I like it or not. This doesn’t seem like the basis for shared agency. After all, your plan involves me being abducted.
But it is still a case in which we each intend that we go to New York together and we do. So, apparently, the conditions of the Simple Theory are met (or almost met) and yet there is no shared agency.
The mafia case fails as a counterexample to the Simple Theory of Joint Action because if you go through with your plan, my actions won’t be appropriately related to my intention.
And, on the other hand, if you don’t go through with your plan, then it is at best unclear that your having had that plan matters for whether we have shared agency.
What seems to be wrong in the Mafia Case is not that the agent’s need further intentions, but just that if their intentions don’t connect to their actions in the right way then there won’t be intentional joint action.
Bratman seems to be aiming to identify intentions whose fulfilment requires shared agency. But is this necessary? It seems to me that what matters is that the Simple Theory as a whole distingiushes shared agency from parallel but merely individual agency, not that it does so by way of fulfilment conditions of intentions.
Contrast friends walking together in the way friends ordinarily walk, which is a paradigm example of joint action, with two gangsters who walk together like this … Gangster 1 pulls a gun on Gangster 2 and says: “let’s walk” But Gangster 2 does the same thing to Gangster 1 simultaneously.
The interdependence of the guns means that their actions can be appropriately related to our intentions.
The conditions of the Simple Theory are met both in ordinary walking together and in walking together in the Tarantino sense. So according to the Simple Theory, both are intentional joint actions.
But walking together in the Tarantino sense is not an intentional joint action unless the central event of Reservoir Dogs (Tarantino, 1992) is also a case of joint action.
Therefore the Simple Theory fails to distinguishing joint action from actions performed in parallel but merely individually.
At least two philosophers responded, independently of each other, by saying that walking together in the Tarantino sense really is a joint action.
My opponents reasoned that each is acting intentionally, and that coercion is no bar to shared agency.
Just here we come to a tricky issue. There is a danger that we will just end up trying to say something systematic about one or another set of intuitions, where nothing deep underpins these intuitions.
This is a real threat; you’ll see that most philosophers are not careful about their starting point in theorising about shared agency. They merely give examples or a couple of contrast cases and off they go. Adopting this undisciplined approach risks achieving nothing more than organising your own intuitions. (It’s fine to organise intuitions on weekends and evenings, but it shouldn’t be your day job.)
Despite the danger of merely organising intuitions, let us consider a further attempted counterexample.1
Imagine two sisters who, getting off an aeroplane, tacitly agree to exact revenge on the unruly mob of drunken hens behind them by standing so as to block the aisle together. This is a joint action. Meanwhile on another flight, two strangers happen to be so configured that they are collectively blocking the aisle. The first passenger correctly anticipates that the other passenger, who is a complete stranger, will not be moving from her current position for some time. This creates an opportunity for the first passenger: she intends that they, she and the stranger, block the aisle. And, as it happens, the second passenger’s thoughts mirror the first’s.
The feature under consideration as distinctive of intentional joint action is present in both the Strangers and the Sisters: each passenger is acting on her intention that they, the two passengers, block the aisle.
But the Strangers, unlike the Sisters, do not perform an intentional joint action.
So the Simple Theory of Joint Action fails to provide a correct answer to the question, What distinguishes genuine joint actions from parallel but merely individual actions?
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