Recall our question, What distinguishes joint actions from parallel but merely individual actions?
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As mentioned earlier ...
‘A first step is to say that what distinguishes you and me from you and the Stranger is that you and
I share an intention to walk together—we (you and I) intend to walk together—but you and the Stranger
do not. In modest sociality, joint activity is explained by such a shared intention; whereas no such
explanation is available for the combined activity of you and the Stranger. This does not, however,
get us very far; for we do not yet know what a shared intention is, and how it connects up with joint
action’ (Bratman, 2009, p. 152).
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What is shared intention?
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Functional characterisation:
shared intention serves to (a) coordinate activities,
(b) coordinate planning, and
(c) structure bargaining
‘We seek ... a construction of interconnected intentions and other
related attitudes ... that would
... play the roles characteristic of shared intention.’
(Bratman, 2014, p. 32)
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To illustrate: if we share an intention that we cook dinner, this shared intention
will (iii) structure bargaining insofar as we may need to decide what to cook or
how to cook it on the assumption that we are cooking it together; the shared
intention will also require us to (ii) coordinate our planning by each bringing
complementary ingredients and tools, and to (i) coordinate our activities by preparing
the ingredients in the right order.
The functional characterisation is really important: if we accept it, then
it tells a lot about what shared intentions could and could not be.
In particular, it either rules out Searle’s account or at least shows that
the account is not clearly an account of shared intention because it
does not explain how the attitude Searle characterises, the ‘we-intention’
could coordinate activities, coordinate planning and structure bargaining.
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inferential integration ... [illustrate with planning example
where you have to plan both individual and joint action]
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normative integration (e.g. agglommeration)
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[illustrate agglomeration for individual case first, then joint]
These points are extremely simple but also extremely powerful.
They are powerful because they create problems for many approaches
to shared agency. Consider Searle’s view again. He thinks that shared
intentions are not intentions but a new, sui generis kind of attitude
(which is why he uses the term ‘we-intentions’).
If you think this, you have to explain how come the new attitudes are
inferentially and normatively integrated with ordinary intentions.
(I’m not saying this can’t be done, just that doing it is challenging,
and certainly not something that Searle has attempted as far as I know.)
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We’ll shortly see how the substantial account is built step by step.
But maybe it’s helpful to mention the strategy
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the construction ...
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‘Our shared intention to paint together involves your intention that we paint and my
intention that we paint.’
(Bratman, 2014, p. 12)
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This is roughly what the Simple Theory said
This might seem completely innocuous, but it is interestingly controversial.
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Given what I said earlier, I don’t think the mafia case actually motivates step 2.
But I did provide other cases (the Tarantino walkers and blocking the asile) which
do seem to motivate step 2.
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star: complication ‘and that the route from these intentions to our joint
activity satisfies the connection condition’ (Bratman, 2014, p. 52).
On the connection condition:
It is ‘the condition that specifies the nature of [the] explanatory relation’ between
shared intention and joint action (Bratman, 2014, p. 78)..
‘the basic idea is that what is central to the connection condition is that each is responsive
to the intentions and actions of the other in ways that track the intended end of the joint
action—where all this is out in the open.’ (Bratman, 2014, p. 79).
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We intend to paint the house, but I blue and you red.
Earlier work: I trick you ...
In the book: ‘we have a problem. In a case of shared intention we will normally try to resolve that problem by making
adjustments in one or both of these sub-plans, perhaps by way of bargaining, in the direction of co-possibility. So we want
our construction to account for is standard social norm-responsive functioning of the shared intention.’
(Bratman, n.d., p. 53)
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meshing subplans are required
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star: meshing
‘The sub-plans of the participants \emph{mesh} when it is possible that all of these
sub-plans taken to gether be successfully executed.’
(Bratman, 2014, p. 53)
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So much for step 2; now we come to the last major step
(I’m skipping some details.)
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step 3
‘there is common knowledge among the participants of the conditions cited in this construction’
(Bratman, 2014, p. 58)
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Why impose the common knowledge condition?
Before discussing this [I might have to skip discussion of this,
but there is a useful quote on the handout], let me
provide a summary of where we are with Bratman’s account.
Why require common knowledge in the construction of shared intention?
‘in shared intention the fact of the shared intention will normally be out in the open:
there will be public access to the fact of shared intention.
Such public access to the shared intention will normally be involved in further
thought that is characteristic of shared intention, as when we plan together how
to carry out our shared intention. Since such shared planning about how to carry
out our shared intention is part of the normal functioning of that shared intention,
we need an element in our construction of shared intention whose functioning
supports some such thinking of each about our shared intention.’
(Bratman, 2014, p. 57)
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These are the conditions that we have been discussing.
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Note that these conditions are offered as sufficient but not necessary.
(Bratman originally claimed that they were necessary and sufficient, but
nothing in the construction rules out alternative realisations of the functional
characterisation of shared intention.)
Are sufficient conditions sufficient for achieving Bratman’s aims?
Bratman’s pitch is this.
Recall the continuity thesis (‘once God created individual planning agents and ... they
have relevant knowledge of each other’s minds, nothing fundamentally new--conceptually,
metaphysically, or normatively--needs to be added for there to be modest sociality.’ p.8)
Bratman reasons that if we can give sufficient conditions for shared agency that
are consistent with the continuity thesis, then our default assumption should be that
shared agency does not require concepual, metaphysical or normative innovation.
So if we accept Bratman’s sufficient conditions, then we should also accept the
continuity thesis.
(There might issues about whether merely sufficient conditions are enough to fulfil his aim
of providing a framework for theorising about shared agency; more on this when we
come to consider joint action and development.)
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So Bratman provides a candidate answer to the question.
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Does the candidate answer avoid counterexamples?
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And does Bratman’s candidate answer meet our aim of providing a theoretical framework
that can help us in investigating for psychology and formal models?
(I guess we will see later how useful it is, when we come to the psychological discoveries
and formal models.)
Bratman’s theory answers question, so meets requirement and takes us
towards the aim.
