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## Joint Commitment and Shared Intention

‘joint commitment underlies a host of central social phenomena in the human realm’;

\citep[p.~400]{gilbert:2014_book}

Gilbert (2013, p. 400)

it is a ‘precondition of the correct ascription’ of acting together, collective belief, shared intention, and more’

\citep[p.~9]{gilbert:2014_book}

Gilbert (2013, p. 9)

The overarching question for the course is:

Which forms of shared agency underpin our social nature?

The first problem, with which we are still grappling, is how to get a basic fix on shared agency.
Here sharing is a metaphor, suggestive and romantic but not conducive to the kind of serious theorising that might eventually support research into how interactions and societies actually work.
Indeed, loose talk about sharing allows lots of philosophers to construct all kinds of theories, each slightly different from the next, none of which seems to work.
I suggested that we can use the method of contrast cases to as a rough and ready criterion for success. That is ...
There are these contrasts between joint action and parallel but merely individual action. For example ...

Joint Action

Parallel but Merely Individual Action

Two people making the cross hit the red square in the ordinary way.

Beatrice & Baldric’s making the cross hit the red square

Two sisters cycling together.

Two strangers cycling the same route side-by-side.

Members of a flash mob simultaneously open their newspapers noisily.

Onlookers simultaneously open their newspapers noisily.

To earn the right to theorise about shared agency

Question

What distinguishes genuine joint actions from parallel but merely individual actions?

This is not the question we ultimately want to answer, but it is a question that we must answer as a preliminary to doing anything else. To earn the right to talk about shared agency, we have to answer this question.
The contrast cases show that this question isn’t easy to answer because the most obvious, simplest things you might appeal to---coordination and common effects---won’t enable you to draw the distinction. In fact, the first contrast cases shows that even some complex things you might appeal to---such as the structure of intentions and knowledge states which Bratman offers in his account of shared agency---don’t enable you to draw the distinction.
Our interest in Gilbert is that she might provide the resources to answer this question. Do we need joint commitment to distinguish genuine joint actions from parallel but merely individual actions?

the ‘shared intention’ strategy

The failure of the Simple View motivates what I will call the ‘shared intention’ strategy, which practically everyone accepts.
According to the shared intention strategy, an account of shared agency consists in an account of shared intention plus an account of how an event must be connected to a shared intention in order to count as a joint action.
This position is widely endorsed.

‘the key property of joint action lies in its internal component [...] in the participants’ having a “collective” or “shared” intention.’

\citep[pp.~444--5]{alonso_shared_2009}

(Alonso 2009, pp. 444-5)

But what is shared intention?
This is our current question. There is much disagreement. But one thing everyone seems to accept:
Shared intention stands to joint action as ordinary, individual intention stands to ordinary individual action.
This is, of course, not a theory but a rough starting point. It is however worth noting some constraints on theories of shared intention.
So the idea is that shared intention is to joint action as intention is to ordinary, individual action.
Of course, invoking shared intention doesn’t by itself amount to explaining anything. It simply takes us in a circle. (Which is not necessarily bad.)
To characterise joint action, we have two tasks: (i) characterise shared intention; (ii) characterise a relation between shared intentions and events such that the events are joint actions.

Can we use joint commitment to characterise shared intention?

First we have to examine a further feature of joint commitment which I have not yet mentioned ...

Gilbert: joint commitment

‘a commitment

by two or more people

of the same two or more people.’

Contrast personal commitment (by me, of me)

joint commitment is ‘the collective analogue of a personal commitment’

Gilbert (2013, p. 85)

Contrast contralateral commitment (by me, of me, to you)

But there’s something I didn’t tell you about joint commitment yet ...

Gilbert: All joint commitments are commitments to emulate, as far as possible, a single body which does something (p. 64).

‘Any joint commitment can be described in a statement of the following form:’ ‘A, B, and so on (or those with property P) are jointly committed as far as is possible (by virtue of their several actions) to emulate a single doer of X’. \citep[p.~311]{gilbert:2014_book}
On emulation: I guess there is a singular version: an actor emulates a single body which believes that $p$, intends to $\phi$, and so on. Likewise, two actors might for some reason share the role (perhaps a young one and an old one). (Here there is not necessarily any joint commitment, but there are commitments with the contents of those which Gilbert specifies as joint commitments.)

‘What is a “single body” [...]? whereas a single human being constitutes a single body [...], a plurality of human individuals does not in and of itself constitute such a body. [...] however, such a plurality can emulate such a body—one with a plurality not only of limbs, eyes, and ears, but also of noses and mouths’

\citep[p.~116]{gilbert:2014_book}

Gilbert (2013, p. 116)

I love the seemingly random ‘not only of limbs, eyes, and ears, but also of noses and mouths’.

‘a “body” here is understood to be a non-collective body.’

BUT: ‘some of the things we may share an intention to do are designed for two or more participants ... Sally and Tim are jointly committed to intend as a body to produce, by virtue of the actions of each, a single instance of a tennis game with the two of them as participants in that game’ (Gilbert 2013, p. 117)

Why does Gilbert insist on the form? I don’t think it adds anything to our understanding of joint commitment as such. But it is essential to Gilbert’s use of joint commitment to analyse social phenomena.
Earlier I asked how there might be such a thing as an aggregate agent. Now I think we can sort of see one possibility. Could aggregate agents come about because we commit to emulating a single body?

Gilbert: All joint commitments are commitments to emulate, as far as possible, a single body which does something (2013, p. 64).

In manifesting any collective phenomenon, we can truly say ‘We have created a third thing, and each of us is one of the parts’

\citep[p.~269]{gilbert:2014_book}

Gilbert (2013, p. 269).

The collective value, belief or intention or whatever is primarily a value, belief or intention of this third thing.
What is this third thing?
I take it to be the single body we have emulated
in doing many things together, the point of doing them together is precisely not to emulate a single body: e.g. in lifting a table, or in foraging for berries, two bodies allow strategies that are impossible with just one body
Emulating as far as possible a single body that intends to wash up is not generally the most efficient way for several people to get the washing up done—Andrea and Heinrich had better exploit the fact that they are two than pretend to be an aggregate animal. The ‘emulating a single body’ form also seems to rule a shared intention to make out after washing up. And if it doesn’t preclude shared intentions to tango outright, it has unfortunate stylistic consequences in implying that those with such intentions are jointly committed to emulate a single body that intends to tango.
What is the motivation for this claim?
If, as Gilbert holds, joint commitments are all commitments to emulate a single body which does something, then the thing to which there is commitment involves nothing collective. Joint commitment thus serves, for Gilbert, as a device which transforms ordinary, singular phenomena (intention, belief or whatever) into collective phenomena with added commitments. To this extent Gilbert’s programme is reductionist: shared values, collective beliefs and the rest are reduced to joint commitments plus ordinary, individual values, beliefs and the rest.

Gilbert’s reductionism

Why does everything but joint commitment require reduction?
So Gilbert’s analysis of joint commitment actually has two parts.

Gilbert on joint commitment

[1] The subject:

‘a commitment

by two or more people

of the same two or more people.’

[2] The content:

All joint commitments are commitments to emulate, as far as possible, a single body which does something (2013, p. 64).

acting together

Gilbert says several things about acting together which I have argued against in this or a previous lecture. In particular, I reject her claims that:
1. Acting together invariably involves shared intention.
2. Acting together invariably involves commitment (I think contralateral commitments are associated with shared intentions, and not directly with joint actions).
3. We know that contralateral commitments exist in virtue of shared intentions.
For this reason I will confine myself to her analysis of shared intention, which I think is independent of what she says about acting together.

shared intention

Actually Gilbert explicitly equates goals with intentions, whereas I think they are importantly different. (More on this later.)

For us to have

a shared intention that we φ

is for us to be jointly committed

to emulate a single body

which

intends to φ

What can be said in favour of this view? Gilbert offers several considerations. Here I’ll mention two; the disjunction criterion and the point about commitment in virtue of intentions.

The Disjunction Criterion

‘when two or more people share an intention, none of them need to have a contributory intention.’

\citep[p.~103]{gilbert:2014_book}

Gilbert (2013, p. 103)

I take it Gilbert would endorse a parallel claim about intention.

Compare blocking

two or more people collectively block an asile, none of them need to individually block an asile.

But: collective vs shared!

I already mentioned this earlier, in a different context.

‘When people regard themselves as collectively intending to do something, they appear to understand that, by virtue of the collective intention, and that alone, each party has the standing to demand explanations of nonconformity [...]. A joint commitment account of collective intention respects this fact. ’

Gilbert (2013, pp. 88–9)

I started by mentioning Gilbert’s proposal that ...

‘joint commitment underlies a host of central social phenomena in the human realm’;

\citep[p.~400]{gilbert:2014_book}

Gilbert (2013, p. 400)

it is a ‘precondition of the correct ascription’ of acting together, collective belief, shared intention, and more’

\citep[p.~9]{gilbert:2014_book}

Gilbert (2013, p. 9)

I think the basis for this proposal is her analysis of shared intention in terms of joint commitment. How successful is that analysis?
There are these contrasts between joint action and parallel but merely individual action. For example ...

Joint Action

Parallel but Merely Individual Action

Two people making the cross hit the red square in the ordinary way.

Beatrice & Baldric’s making the cross hit the red square

Two sisters cycling together.

Two strangers cycling the same route side-by-side.

Members of a flash mob simultaneously open their newspapers noisily.

Onlookers simultaneously open their newspapers noisily.

In favour of Gilbert’s account, a joint commitment to emulate a single body that intends that ... appears absent from the cases of parallel but merely individual action.
The challenge, I think, concerns the necessity of Gilbert’s account. Must sisters cycling together have a joint commitment to emulate a single body that intends to cycle to school? Maybe---we should evaluate Gilbert’s arguments for her position.