A Counterexample to Bratman

Click here and press the right key for the next slide (or swipe left)

also ...

Press the left key to go backwards (or swipe right)

Press n to toggle whether notes are shown (or add '?notes' to the url before the #)

Press m or double tap to slide thumbnails (menu)

Press ? at any time to show the keyboard shortcuts

A Counterexample to Bratman

I want to start by considering an objection to Bratman which I think is misguided, because seeing how this objection is misguided is the key to understanding what is wrong with Bratman’s account.

Having a shared intention involves us each intending that we, you and I, φ together.

Bratman

‘Bratman’s account presupposes the element of sharedness it aims to explain.’

\citep[p.~36]{schmid:2009_plural_bk}

‘It is only because we intend J that I can have intentions of the form “I intend that we J”’

\citep[p.~36]{schmid:2009_plural_bk}

‘Bratman’s ... account of shared intentionality ... fails to give an account of the crucial element of collectiveness that is presupposed at its very base’

\citep[p.~37]{schmid:2009_plural_bk}

[The reply to Schmid is the people who block the asile, or the Tarantino walkers.]

Full quote: ‘Consider the following example. If we jointly intend to meet for lunch today, it does not seem necessary – indeed it is redundant – for me to form an intention of the form “I intend that we meet for lunch today” (rather, I will typically form some we-derivative [Sellars 1980: 99] or participatory [Kutz 2000a] intention of the kind “I intend to call you before noon to arrange a meeting place”). If and only if I take myself to be in a position to have a say in that matter, I might form an additional intention that specifies the content of our we-intention, and this additional intention might be of the form “I intend that we Jx” (e.g., “I intend that we have lunch together at the Japanese restaurant”). But intentions of this sort presuppose shared intentions instead of being their building blocks. It is only because we intend J that I can have intentions of the form “I intend that we Jx”. Thus it seems that Bratman’s “reductive” account of shared intentionality “in terms of attitudes and actions of the individuals involved” (1999: 108) simply fails to give an account of the crucial element of collectiveness that is presupposed at its very base, because he endorses formal individualism.’

Schmid (2009, p. 36)

I think Schmid is wrong that Bratman’s presupposes collectiveness. Quite the opposite: I think it fails to capture collectiveness. So my objection takes a line opposite Schmid’s (and cannot be correct unless his objection is wrong).

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)

Blomberg (personal communication)

Ayesha and Beatrice are bitter rivals. They each have one wrist handcuffed to the steering wheel of the same moving car. They are matched in strength closely enough that neither can decide the car’s course alone: its movements will be a consequence of both of their actions.

Ayesha, determined that Beatrice should die and wishing to die herself, is wondering how she could bring this about. Thinking that she could pull her gun on Beatrice to force her to cooperate, she intends, unilaterally, that they, Ayesha and Beatrice, drive the car off the road and over a cliff.

If they now drive off the cliff in accordance with Ayesha’s intention, they won’t be exercising shared agency. Contrast this case with Thelma and Louise’s better known and more romantic intentional car crash (the two friends evade capture by driving off a cliff together; Khouri 1992). Whereas Thelma and Louise’s escape is a paradigm case of collective agency, the initial episode involving Ayesha and Beatrice does not seem to involve collective agency at all.

But now change how it happens. Let a sudden jolt causes the gun to fly from her hand and land far out of reach. Just as it seems she will have to abandon her intention, it strikes her that Beatrice has an intention which renders the gun unnecessary. For Beatrice, whose thoughts and actions mirror Ayesha’s, plainly intends what Ayesha intends, namely that they drive the car over the cliff. So Ayesha retains this intention and changes her mind only about the means.

Is this change enough to transform Ayesha and Beatrice’s actions into a joint action? If it is, Bratman’s account is in trouble---it would be a counterexample.

I used to think this is a counterexample, but now I’m not so sure. What do you think.

Is it a counterexample?

[btw] A counterexample to the sufficiency of Bratman’s conditions for shared intention is also a counterexample to the Simple View.

a second attempt

\begin{minipage}{\columnwidth}

We have an \emph{unshared intention} that we <J$_1$, J$_2$> where J$_1$$\neq$J$_2$ just if:

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

\item (a) I intend that we J$_1$ and (b) you intend that we J$_2$

\item I intend that we J$_1$ in accordance with and because of la, lb, and meshing subplans of la and lb; you intend that we J$_2$ ...

\item 1 and 2 are common knowledge between us.

\end{enumerate}

\end{minipage}

Our individual subplans concerning our <J$_1$, J$_2$>-ing \emph{mesh} just in case there is some way I could J$_1$ and you could J$_2$ that would not violate either of our subplans but would, rather, involve the successful execution of those subplans.

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)

The conditions for unshared intention are just like those for shared intention except that they concern two distinct activities, J1 and J2.

So for you and I to have an unshared intention that we , ...

If it is possible for Bratman's sufficient conditions for shared intention to be met without relevant irrationality or ignorance, then it is likewise possible for these conditions on unshared intention to be met.

Here is an example of two people who have an unshared intention.

Ayesha and Ahmed. They can each tilt the table, but only along one axis.

(Note that Ayesha can unilaterally intend that they, Ayesha and Ahmed, make the ball hit the red square.)

Ayesha and Ahmed meet the conditions for unshared intention concerning hitting the blue cross and hitting the red square. And their actions are appropriately related to their intentions.

Ayesha and Ahmed are not acting as one (or exercising shared agency). This is not just a matter of their having different intentions, I think. More fundamentally, each sees the other’s intentions merely as constraints to work around or opportunities to exploit. While I don’t think that viewing another’s intentions in this way is entirely incompatible with acting as one, in Ayesha and Ahmed’s case each views the other’s intentions *merely* as opportunities to exploit or constraints to work around. And this is, surely, incompatible with acting as one. (*Qualified in the book chapter for Catrin Misselhorn.)

If you think Ayesha and Ahmed are having a bad hair day, you should see Beatrice and Baldric ...

Now explain that Ayesha and Ahmed have an unshared intention, but Beatrice and Baldric have a shared intention.

I claim that Beatrice and Baldric have a shared intention that they J$_1$ only if Ayesha and Ahmed have a shared intention. This claim follows from the similarities of the two cases. The only difference is that Beatrice and Baldric happen to have same task, whereas Ayesha and Ahmed have different tasks. But neither Beatrice nor Baldric makes use of the fact that they have the same task. So if we consider how Beatrice and Baldric's case differs from Ayesha and Ahmed’s, we can see that these differences do not plausibly amount to a difference with respect to shared agency. Shared intention cannot feature in one case but not the other.

This is a bit delicate. I am supposing that Beatrice and Baldric are each making use of the fact that Beatrice intends J1 and of the fact that Baldric intends that J2, but that they are neglecting to make any use of the fact that J1=J2.

So the only difference is that Beatrice and Baldric happen to have same task, whereas Ayesha and Ahmed have different tasks. But neither Beatrice nor Baldric makes use of the fact that they have the same task.

Beatrice does rely on the fact Baldric intends that they J1, of course; but she does not rely on the fact that what Baldric intends is what she intends.

true? A&A make use of?
Ayesha intends J₁ ✓ ✓
Ahmed intends J₂ ✓ ✓
J₁=J₂ ✗ ✗

	true?	A&A make use of?
Ayesha intends J₁	✓	✓
Ahmed intends J₂	✓	✓
J₁=J₂	✗	✗

true? B&B make use of?
Beatrice intends J₁ ✓ ✓
Baldric intends J₂ ✓ ✓
J₁=J₂ ✓ ✗

	true?	B&B make use of?
Beatrice intends J₁	✓	✓
Baldric intends J₂	✓	✓
J₁=J₂	✓	✗

So 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.

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.

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)

So I reject two attempts to say what is involved in acting as one. The Simple View fails because it is possible to meet this condition while walking in the Tarantino sense, and the Bratman-esque Shared Intention Account fails because it’s possible to meet these conditions in a situation where you are merely treating others’ intentions as opportunities to exploit and constraints to work around.

Acting as one requires more than this (and perhaps less than this too). But what is missing?

The problem I think is that we are failing to capture the agents’ perspective. Acting as one is in part a matter of how things seem to the agent. It is also, I think, partly a matter of the agents exploiting the fact that they each intend the same thing, or that their actions have a collective goal. But how can we get from such an intuition to a theoretical account of acting as one?

Keyboard Shortcuts?

A Counterexample to Bratman

Keyboard Shortcuts`?`