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Team Reasoning and Aggregate Agents

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This section depends on you having studied some sections from a previous lecture:

  • Question Session 05 (introduces the notion of an aggregate subject and Pettit (2014)’s idea about self-represention could bring them into existence)

  • What Are Preferences? (to have preferences, your choices must satisfy axioms including transitivity, completeness and independence. If your choices do not satisfy the axioms, this does not mean that your preferences are irrational or defective: it means that you do not have preferences at all.)

  • What Is Team Reasoning?

A Clarification

Why do aggregate subjects that are a consequence of team reasoning neither require the kind of self-reflection that Pettit (2014)’s idea involves nor presuppose shared agency? It is because

Sugden’s ‘account of team agency does not require that the individuals who participate in it agree to do so, or openly express their willingness to do so. What is required instead is that there is confidence among the members of the team that each of them will engage in team-directed reasoning with respect to a common set of team preferences.’ (Sugden, 2000, p. 196)

A Qualification

Sugden himself would disagree with the view about what preferences are that is assumed in this section. (This view about preferences was introduced in What Are Preferences?). Sugden rejects that view on the grounds that:

‘On some revealed-preference accounts, preference is nothing more than a disposition that a person may come to have, for whatever reason or for none, which prompts her to choose actions of one kind rather than actions of another. However, such an interpretation of preference seems not to acknowledge the sense in which the theory of rational choice is a theory of reasoning.1 It would be more faithful to the practice of rational choice theory to say that a person’s preferences are whatever she takes to be choice-relevant reasons, all things considered.’ (Sugden, 2000, p. 197)

This requires that we, as researchers, have a shared understanding of preference as ‘taking something to be a choice relevant reason’ and that this understanding is not anchored by decision theory.

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aggregate subject : A subject whose proper parts are themselves subjects. A paradigm example would be a Portuguese man o' war (Physalia physalis), which is an animal that can swim and eat and whose swimming and eating is not simply a matter of the swimming or eating of its constituent animals. Distinct from, but sometimes confused with, a plural subject.
decision theory : I use ‘decision theory’ for the theory elaborated by Jeffrey (1983). Variants are variously called ‘expected utility theory’ (Hargreaves-Heap & Varoufakis, 2004), ‘revealed preference theory’ (Sen, 1973) and ‘the theory of rational choice’ (Sugden, 1991). As the differences between variants are not important for our purposes, the term can be used for any of core formal parts of the standard approaches based on Ramsey (1931) and Savage (1972).
model : A model is a way some part or aspect of the world could be.


Gold, N., & Sugden, R. (2007). Collective intentions and team agency. Journal of Philosophy, 104(3), 109–137.
Hargreaves-Heap, S., & Varoufakis, Y. (2004). Game theory: A critical introduction. London: Routledge. Retrieved from
Jeffrey, R. C. (1983). The logic of decision, second edition. Chicago: University of Chicago Press.
Pettit, P. (2014). Group Agents are Not Expressive, Pragmatic or Theoretical Fictions. Erkenntnis, 79(9), 1641–1662.
Ramsey, F. (1931). Truth and probability. In R. Braithwaite (Ed.), The foundations of mathematics and other logical essays. London: Routledge.
Savage, L. J. (1972). The foundations of statistics (2nd rev. ed). New York: Dover Publications.
Sen, A. (1973). Behaviour and the Concept of Preference. Economica, 40(159), 241–259.
Steele, K., & Stefánsson, H. O. (2020). Decision Theory. In E. N. Zalta (Ed.), The Stanford Encyclopedia of Philosophy (Winter 2020). Metaphysics Research Lab, Stanford University.
Sugden, R. (1991). Rational Choice: A Survey of Contributions from Economics and Philosophy. The Economic Journal, 101(407), 751–785.
Sugden, R. (2000). Team preferences. Economics and Philosophy, 16, 175–204.
Trommershäuser, J., Maloney, L. T., & Landy, M. S. (2009). Chapter 8 - The Expected Utility of Movement. In P. W. Glimcher, C. F. Camerer, E. Fehr, & R. A. Poldrack (Eds.), Neuroeconomics (pp. 95–111). London: Academic Press.


  1. Is decision theory (‘the theory of rational choice’) a theory of reasoning? Arguably it is a model which can be applied to various projects including understanding processes that might be called reasoning (see Are Objections to Decision Theory also Objections to the Dual Process Theory of Action?) as well as to things that are probably not reasoning (for example, motor control; see Trommershäuser, Maloney, & Landy, 2009). As reflection on these applications shows, to say that preference is a construct of decision theory does not imply that ‘preference is nothing more than a disposition … to choose actions’.