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How can we combine formal and philosophical approaches to joint action? One initially promising idea is to use team reasoning to construct a theory of shared intention, thereby providing a candidate solution to the The Problem of Joint Action. We have seen how this could be done. But does it succeed? Is the theory of shared intention true; and, if so, does it actually solve The Problem of Joint Action?

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joint action : Many of the things we do are, or could be, done with others. Mundane examples favoured by philosophers include painting a house together (Bratman, 1992), lifting a heavy sofa together (Velleman, 1997), preparing a hollandaise sauce together (Searle, 1990), going to Chicago together (Kutz, 2000), and walking together (Gilbert, 1990). These examples are supposed to be paradigm cases of a class of phenomena we shall call ‘joint actions’.
Researchers have used a variety of labels including ‘joint action’ (Brooks, 1981; Sebanz, Bekkering, & Knoblich, 2006; Knoblich, Butterfill, & Sebanz, 2011; Tollefsen, 2005; Pettit & Schweikard, 2006; Carpenter, 2009; Pacherie, 2010; Brownell, 2011; Sacheli, Arcangeli, & Paulesu, 2018; Meyer, Wel, & Hunnius, 2013), ‘social action’ (Tuomela & Miller, 1985), ‘collective action’ (Searle, 1990; Gilbert, 2010), ‘joint activity’ (Baier, 1997), ‘acting together’ (Tuomela, 2000), ‘shared intentional activity’ (Bratman, 1997), ‘plural action’ (Schmid, 2008), ‘joint agency’ (Pacherie, 2013), ‘small scale shared agency’ (Bratman, 2014), ‘intentional joint action’ (Blomberg, 2016), ‘collective intentional behavior’ (Ludwig, 2016), and ‘collective activity’ (Longworth, 2019).
We leave open whether these are all labels for a single phenomenon or whether different researchers are targeting different things. As we use ‘joint action’, the term applies to everything any of these labels applies to.
shared intention : An attitude that stands to joint action as ordinary, individual intention stands to ordinary, individual action. It is hard to find consensus on what shared intention is, but most agree that it is neither shared nor intention. (Variously called ‘collective’, ‘we-’ and ‘joint’ intention.)
team reasoning : ‘somebody team reasons if she works out the best possible feasible combination of actions for all the members of her team, then does her part in it’ (Bacharach, 2006, p. 121).
The Problem of Joint Action : What distinguishes doing something jointly with another person from acting in parallel with them but merely side by side?


Bacharach, M. (2006). Beyond individual choice. Princeton: Princeton University Press. Retrieved from
Baier, A. C. (1997). Doing Things With Others: The Mental Commons. In L. Alanen, S. Heinamaa, & T. Wallgren (Eds.), Commonality and particularity in ethics (pp. 15–44). Palgrave Macmillan.
Blomberg, O. (2016). Common Knowledge and Reductionism about Shared Agency. Australasian Journal of Philosophy, 94(2), 315–326.
Bratman, M. E. (1992). Shared cooperative activity. The Philosophical Review, 101(2), 327–341.
Bratman, M. E. (1997). I intend that we J. In R. Tuomela & G. Holmstrom-Hintikka (Eds.), Contemporary action theory, volume 2: Social action. Dordrecht: Kluwer.
Bratman, M. E. (2014). Shared agency: A planning theory of acting together. Oxford: Oxford University Press. Retrieved from
Brooks, D. H. M. (1981). Joint action. Mind, 90(357), 113–119. Retrieved from
Brownell, C. A. (2011). Early Developments in Joint Action. Review of Philosophy and Psychology, 2, 193–211.
Carpenter, M. (2009). Just how joint is joint action in infancy? Topics in Cognitive Science, 1(2), 380–392.
Gilbert, M. P. (1990). Walking together: A paradigmatic social phenomenon. Midwest Studies in Philosophy, 15, 1–14.
Gilbert, M. P. (2010). Collective action. In T. O’Connor & C. Sandis (Eds.), A companion to the philosophy of action (pp. 67–73). Oxford: Blackwell.
Knoblich, G., Butterfill, S. A., & Sebanz, N. (2011). Psychological research on joint action: Theory and data. In B. Ross (Ed.), Psychology of learning and motivation (Vol. 51, pp. 59–101). San Diego, CA: Academic Press.
Kutz, C. (2000). Acting together. Philosophy and Phenomenological Research, 61(1), 1–31.
Longworth, G. (2019). Sharing non-observational knowledge. Inquiry, 0(0), 1–21.
Ludwig, K. (2016). From Individual to Plural Agency: Collective Action. Oxford University Press.
Meyer, M., Wel, R. P. R. D. van der, & Hunnius, S. (2013). Higher-order action planning for individual and joint object manipulations. Experimental Brain Research, 225(4), 579–588.
Pacherie, E. (2010). The phenomenology of joint action: Self-agency vs. Joint-agency. In A. Seemann (Ed.), Joint action. MIT Press.
Pacherie, E. (2013). Intentional joint agency: Shared intention lite. Synthese, 190(10), 1817–1839.
Pettit, P., & Schweikard, D. (2006). Joint Actions and Group Agents. Philosophy of the Social Sciences, 36(1), 18–39.
Sacheli, L. M., Arcangeli, E., & Paulesu, E. (2018). Evidence for a dyadic motor plan in joint action. Scientific Reports, 8(1), 5027.
Schmid, H. B. (2008). Plural action. Philosophy of the Social Sciences, 38(1), 25–54.
Searle, J. R. (1990). Collective intentions and actions. In P. Cohen, J. Morgan, & M. E. Pollack (Eds.), Intentions in communication (pp. 90–105). Cambridge: Cambridge University Press.
Sebanz, N., Bekkering, H., & Knoblich, G. (2006). Joint action: Bodies and mind moving together. Trends in Cognitive Sciences, 10(2), 70–76.
Tollefsen, D. (2005). Let’s pretend: Children and joint action. Philosophy of the Social Sciences, 35(75), 74–97.
Tuomela, R. (2000). Cooperation: A Philosophical Study. Dordrecht: Springer.
Tuomela, R., & Miller, K. (1985). We-Intentions and Social Action. Analyse & Kritik, 7(1), 26–43.
Velleman, D. (1997). How to share an intention. Philosophy and Phenomenological Research, 57(1), 29–50.