Lecture 07 | Joint Action

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Question

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

The Simple View

Two or more agents perform an intentional joint action
exactly when there is an act-type, φ, such that
each agent intends that
they, these agents, φ together
and their intentions are appropriately related to their actions.

Recall our earlier contrast cases ...

***BRATMAN's DIAGNOSIS - have to intend to do it by way of the other’s intentions. This is what is wrong in blocking the aisle shared agency means connecting with each other as agents, not merely as bodies

Bratman’s brilliant idea for avoiding this sort of problem is to suggest that we don’t just each intend the action but rather we each intend to act by way of the other's intentions.

We can put this by saying that our intentions must interlock: mine specify yours and yours mind.

Now this appeal to interlocking intentions enables Bratman to avoid counterexamples like the Tarantino walkers; if I intend that we walk by way of your intention that we walk, I suppose can't rationally also point a gun at you and coerce you to walk.

‘each agent does not just intend that the group perform the […] joint action.

‘Rather, each agent intends as well that the group perform this joint action in accordance with subplans (of the intentions in favor of the joint action) that mesh’

(Bratman 1992: 332)

`each agent does not just intend that the group perform the […] joint action. Rather, each agent intends as well that the group perform this joint action in accordance with subplans (of the intentions in favor of the joint action) that mesh' \citep[p.\ 332]{Bratman:1992mi}.

Our plans are \emph{interconnected} just if facts about your plans feature in mine and conversely.

‘shared intentional [i.e.\ collective] agency consists, at bottom, in interconnected planning agency of the participants’ \citep{Bratman:2011fk}.

In making this idea more precise, Bratman proposes sufficient conditions for us to have a shared intention that we J ... ... the idea is then that an intentional joint action is an action that is appropriately related to a shared intention.

We have a shared intention that we J if

‘1. (a) I intend that we J and (b) you intend that we J

‘2. I intend that we J in accordance with and because of la, lb, and meshing subplans of la and lb; you intend [likewise] …

‘3. 1 and 2 are common knowledge between us’

(Bratman 1993: View 4)

\begin{minipage}{\columnwidth}

\emph{Bratman’s claim}. For you and I to have a collective/shared intention that we J it is sufficient that:

\begin{enumerate}[label=({\arabic*}),itemsep=0pt,topsep=0pt]

\item `(a) I intend that we J and (b) you intend that we J;

\item `I intend that we J in accordance with and because of la, lb, and meshing subplans of la and lb; you intend that we J in accordance with and because of la, lb, and meshing subplans of la and lb;

\item `1 and 2 are common knowledge between us' \citep[View 4]{Bratman:1993je}

\end{enumerate}

\end{minipage}

Note that these conditions are sufficient but not plausibly necessary. If sharing a smile is a joint action, and if human infants in their first year of life are incapable of knowing things about other's knowledge of their intentions about the other's intentions, then to suppose that these conditions were necessary would be to imply that you can't share a smile with an infant.

So the cleanest objection to Bratman will be a counterexample to the sufficiency of his account.

I take this case to be an objection to the idea that we can explain acting as one by appeal to shared intention if we also accept Bratman's claims about what is sufficient for shared intention.

Luke’s objection

Ayesha intends that they J1 in accordance with and because of Ahmed’s intention that they J2
This is tantamount to Ayesha intending that Ahmed’s intention be fulfilled.
Manifestly, they only way for Ahmed’s intention to be fulfilled is if Ayesha and Ahmed J2.

Can Ayesha rationally fail to intend that they, Ayesha and Ahmed, J2?

If not, they meet Bratman’s sufficient conditions for having a shared intention that they J2.

So, at least provisionally, we can add Beatrice & Baldric to the right side of our list of cases of parallel but merely individual action.

This is a case where we have interconnected planning but no shared agency.

I'll strengthen the case for denying that BnB have a shared intention later by constructing a contrasting case in which there really is a shared intention.

(I might mention that there are also mundane counterexamples.)

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.

Question

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

So far I have offered objections to (a) The Simple View and (b) Bratman’s account.

We’re still looking for an answer to this question. One possibility (introduced yesterday) is that we can find an answer by considering commitment.

Gilbert on Joint Commitment

Here is our basic picture.

Intentions are associated with commitments.

Shared intentions are associated with commitments to each other (contralateral commitments).

Gilbert thinks there is something missing from this picture: joint commitments ...

Gilbert: joint commitment

Here are two sentences:

The tiny drops fell from the bottle.

- distributive

The tiny drops soaked Zach’s trousers.

- collective

I suggest that the contrast here is clear, and isn’t particular to psychological or normative states.

So my question was, How should we understand the idea that the commitment is ‘by two or more people’? I’ve suggested that this is simply a matter of collective predication. I should warn you, however, that this isn’t something Gilbert actually says, and it isn’t obvious to me that this must be her view.

Gilbert: joint commitment

‘a commitment

by two or more people

of the same two or more people.’

Contrast personal commitment (by me, of me)

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

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

Gilbert (2013, p. 85)

I’ve been suggesting that

A joint commitment is a commitment we have collectively,

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

‘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’.

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).

To repeat, I’ve been suggesting that

A joint commitment is a commitment we have collectively,

so

a joint commitment is simply a commitment.

Compare: a collective blocking is simply a blocking.

This explains why there may not be very much to say about what joint commitments are, and in particular, why a reductive account may not be needed.

But Gilbert says

joint commitments have a special kind of content too

and that joint commitments entail contralateral commitments,

which indicates that

a joint commitment is not simply a commitment.

commitment:

personal

contralateral

collective (?)

shared (?)

sense of (?)

How closely should we follow Gilbert in thinking about commitment? I suspect we will eventually need all of these to understand shared agency. As far as I know, Gilbert is the leading authority in this area. And her position is largely untenable. I know that some relatively new people are moving into this area in a big way (especially John Michael), so I expect to see some major developments. And this is asking a lot, I know, but maybe you can contribute in your own work.

Distributive / Collective / Shared

distributive

conclusion

In conclusion, ...

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