Michael E. Bratman Routledge Lecture - Shared Intentional Activity (SIA) - Conceptual Foundations

Oct 22, 2026

Lecture slides by Michael E. Bratman develop a philosophical account of shared intentional activity (SIA). The material distinguishes SIAs from mere strategic interaction and explicit promises, emphasizing both instrumental and non-instrumental importance for everyday life. It frames SIAs as central for theories of thinking and acting together, then motivates an account of small-scale SIA under conditions lacking asymmetric authority. Competing ideas from Searle and Gilbert are contrasted with an alternative approach grounded in individual planning agency, yielding a reductive yet multi-faceted model that supports continuities across conceptual, metaphysical, and normative levels.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages42

Reading Time1 h 46 min

AccessFree to download

Shared intentional activity (SIA)

Examples of SIAs

Significance of these phenomena

Importance for life and special domains

In contrast to SIA

Mere strategic interaction

Explicit promises

Small scale SIA

Initial aim and background condition

A fundamentally new capacity (and associated concept)?

Searle’s we-intention

Gilbert’s joint commitment

My alternative approach

Grounding shared agency in individual planning

Michael E. Bratman Routledge Lecture June 2014 1 3 Shared intentional activity (SIA) 􀂀 We have the capacity for shared intentional (and shared cooperative) activity. 􀂀 Examples: we paint the house together, dance together, have a conversation together, perform an experiment together, put on a play together, walk together (Gilbert) . 4 Significance of these phenomena 􀂀 Such SIAs are important in our lives, both instrumentally and noninstrumentally. 􀂀 Of concern in relevant special domains (law, political theory, cognitive psychology, business ethics …) 􀂀 A theory of human thought and human action needs to be, in part, a theory of thinking and acting together. 5 In contrast to SIA 1. Mere strategic interaction (e.g., just walking alongside each other) . 2. Explicit promises (Hume’s rowers row together “tho’ they have never given promises to each other.”) 6 Small scale SIA Initial aim: articulate ideas useful in understanding small-scale SIA, in the absence of asymmetric authority. Duets and quartets rather than orchestras with conductors. 7 A fundamentally new capacity (and associated concept)? 􀂀 John Searle: new attitude of “we-intention”(vs. ordinary intentions involved in individual agency) in the minds of participating individuals. 􀂀 Margaret Gilbert: new inter-relation of “joint commitment” (involves special mutual obligations) between the participants. 􀂀 Such approaches are non-reductive and single-faceted. 8 My alternative approach 􀂀 Begin with a rich theory of individual planning agency. 􀂀 Aim for a multi-faceted model of our shared agency, one that is grounded in structures of individual planning agency. 9 A reductive, multi-faceted model 􀂀 Use the theoretical resources available within the theory of individual planning agency to“construct”/provide sufficient conditions for shared agency. 􀂀 Thereby support continuities between individual planning agency and shared agency: conceptual, metaphysical, normative. 10

FAQs

What does shared intentional activity (SIA) mean in the lecture?

SIA is the capacity for shared intentional (and shared cooperative) activity, where people act together with a shared intention.

How does SIA differ from mere strategic interaction and explicit promises?

The lecture contrasts SIA with mere walking alongside each other (strategic interaction) and with explicit promises, which can involve cases like Hume’s rowers without reciprocal promises.

What is the lecture’s alternative approach to explaining shared agency?

It begins with a rich theory of individual planning agency and builds a multi-faceted model of shared agency using resources within that individual-planning framework to provide sufficient conditions for shared agency.

Oct 22, 2026

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