Three Strategies: Plural, Aggregate and Reductive

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Three Strategies: Plural, Aggregate and Reductive

ultimate aim	individual vs plural subjects of mental states
intermediate step	collective vs distributive interpretations of sentences

The tiny leaves blocked the drain

The tiny leaves blocked the drain.

The people weigh 227kg.

The people broke the elevator.

The injections saved her life

-- collective vs distributive

All have collective interpretations

Check you can understand this. Come up with another sentence that is naturally interpreted collectively.

ultimate aim	individual vs plural subjects of mental states
intermediate step	collective vs distributive interpretations of sentences

The tiny leaves blocked the drain

The tiny leaves blocked the drain.

The people weigh 227kg.

The people broke the elevator.

The injections saved her life

-- collective vs distributive

The people intend to break the elevator.

-- collective vs distributive???

It can be interpreted distributively. Can it also be interpreted collectively? And, if so, could it be true on the collective interpretation. Can one mental state be yours and mine?

collective -> suprapersonal intentions (and minds) (?)

There are people (e.g. Ludwig (2016)) who think that you can have a true collective interpretation without suprapersonal intentions.

This need not detail us. I am not fixed on the idea that there is some superficial linguistic marker. Rather the point is that we understand the notion of suprapersonal weight. So it is at least coherent to suppose that there are suprapersonal intentions. And this is what the idea that there are plural subjects of intentions amounts to

We saw this in Bratman’s account ...

What is shared intention?

Functional characterisation:

shared intention serves to (a) coordinate activities, (b) coordinate planning and (c) structure bargaining

Constraint:

Inferential integration... and normative integration (e.g. agglomeration)

Substantial account:

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)

All of the intentions have individual subjects

all intentions have individual subjects

On accounts like Bratman’s or Gilbert’s, ‘it makes some sense to say that the result is a kind of shared action: the individual people are, after all, acting intentionally throughout.

However, in a deeper sense, the activity is not shared: the group itself is not engaged in action whose aim the group finds worthwhile, and so the actions at issue here are merely those of individuals.

Thus, these accounts ... fail to make sense of a ... part of the landscape of social phenomena’

(Helm, 2008, pp. 20--1)

Helm (2008, pp. 20-1)

Start with Helm’s challenge ([because I can answer it at the end]).

This is bad: who can explain what sharing amounts to? This is just a metaphor. Our problem is to discipline the metaphor, not to write as if we already understood it.

It is hard to understand what Helm is aiming for here, but I think the idea is that the actions should be not merely those of individuals but of the group itself.

The objection says something is missing, but actually our interest is driven by the thought that both Gilbert’s and Bratman’s approaches are inadqeuate as attempts to characterise shared agency.

How to make sense of this idea?

aggregate subject

I think Helm wants what I will call an ‘aggregate subject’. (He uses the term ‘plural robust agent’, but this is because he ignores a distinction between aggregate and plural subjects which will be important later.)

Meet an aggregate animal, the Portuguese man o' war (Physalia physalis), which is composed of polyps.

Here you can say that ‘the group [of polyps] itself’ is engaged in action which is not just a matter of the polyps all acting.

To illustrate, consider how it eats. Wikipedia: ‘Contractile cells in each tentacle drag the prey into range of the digestive polyps, the gastrozooids, which surround and digest the food by secreting enzymes that break down proteins, carbohydrates, and fats, while the gonozooids are responsible for reproduction.’

This jellyfish-like animal is a crude model for the sort of aggregate agent Helm (and others) suggest we need.

But how can such a thing exist? Humans do not mechanically attach themselves in the way that the polyps making up that jellyfish-like animal do.

So how are aggregate agents possible?

‘[...] a distinctive mode of practical reasoning, team reasoning, in which agency is attributed to groups.’

(Gold & Sugden, 2007)

So these researchers are aiming to build a kind of aggregate subject.

They think, in a nutshell, that aggregate subjects are not only a consequence of self-reflection, but can also arise through (a special mode of) reasoning about what to do.

Gold and Sugden (2006)

Need a bit of a recap (or even first exposure ...)

‘somebody team reasons if she works out the best possible feasible combination of actions for all the members of her team, then does her part in it.’

(Bacharach, 2006, p. 121)

What counts as best possible?

An individual who engages in team-directed reasoning appraises alternative arrays of actions by members of the team in relation to [...] team-directed preferences.’

(Sugden, 2000)

Preferences of teams just like preferences of the individuals. (Team really is considered as an aggregate agent.)

‘At the level of the team, team preference is a ranking of outcomes which is revealed in the team's decisions.’

(Sugden, 2000)

Why suppose that team reasoning explains how

there could be aggregate subjects?

we take* ourselves to be components of an aggregate agent
through team reasoning, we ensure that the aggregate agent’s choices maximise the aggregate agent’s expected utility
the aggregate agent has preferences (literally)

Team reasoning gets us aggregate subjects, I think. After all, we can explicitly identify as members of a team, explicitly agree team preferences, and explicitly reason about how to maximise expected utility for the team.

game theory is already agnostic about agents ...

individual adult humans (suspects under arrest)

bower birds (maraud/guard nests)

business organisations (product pricing)

countries (international environmental policy)

(Dixit, Skeath, & Reiley, 2014, p. chapter 10)

... so aggregates with preferences that maximise their expected utility are already in view.

How?

aggregate subject

contrast aggregate vs plural

As a preliminary we need to be clear about what we are getting ourselves into with aggregate subjects, particularly as even the best papers on this topic are not entirely clear and the terminology is confusingly diverse.

The tiny leaves formed an impenetrable barrier

which blocked the drain.

Let’s start with a super-simple analogy (I hope this isn’t too simple).

If some tiny leaves collectively block a drain, they are the plural subject of the blocking. By contrast, suppose some tiny leaves form an impenetrable barrier which blocks the drain. The impenetrable barrier, although composed of nothing but the leaves, is distinct from the leaves. Similarly, if we collectively intend or believe something (assuming such a thing is possible), we (not something distinct from us, but simply you and I) are the plural subject of that intention or belief. If we are components of an aggregate, or members of a group, that intends or believes something, then there is an aggregate subject (not you and I but something distinct from, albeit composed from, us) which intends or believes.

This about a plural subject, the tiny leaves.

This about an aggregate subject, the impenetrable barrier.

With this in mind, let’s step back and get our teminology straight.

Plural subject

-- some individuals who collectively have an attitude.

Aggregate subject

-- a subject with multiple parts that are subjects.

Identical to the individuals.

Distinct from the individuals.

When we have plural subjects, there is nothing distinct from the subjects which is the subject of the predication. The plural subject is identical to the individuals.

But when we have aggregate subjects, there is something distinct. The individuals \emph{comprise} the aggregate subject but the aggregate subject is not \emph{identical} to those individuals.

This is potentially confusing because the aggregate subject might be nothing but an aggregate of the individuals who are the plural subject.

Could not involve other individuals.

The component individuals can change.

Still we know they are different because different counterfactuls are true of the plural subject and of the aggregate subject.

To illustrate, the man o’ war is nothing but the polyps, but the man o’ war can surive the loss of one polyp and the addition of another whereas the polyps can’t (they aren’t *these* polyps anymore if there is one missing or one addded).)

True: Collectively form an aggregate subject.

False: Does not form an aggregate subject.

Even where there is a plural subject and an aggregate subject and the componets of the aggregate subject are the plural subject, still different things can be true of the aggregate subject and of the plural subject

For example, he animals that comprise an aggregate animal do collectively comprise an aggregate animal; but the aggregate animal itself does not comprise an aggregate animal.

False: Do not collectively sting or eat.

True: Does sting and eat.

For example, an aggregate animal, the Portuguese man o' war (Physalia physalis), stings and eats but the animals (polyps) that compose it do not collectively sting or eat.

Gilbert, Schmid

Pettit, List, Helm, ?Gilbert

The philosophers whose current focus is plural subjects or aggregate subjects.

Note the contrast between e.g. Pettit (aggregate subject) and Schmid (plural subject) According to Schmid, ‘Feelings can indeed be shared in the simplest sense of the word,’ the sense in which ‘sharing is not a matter of type, or of qualitative identity (i.e. of having different things that are somehow similar), but a matter of token, or numerical identity’ (2009, p. 88). On Schmid’s view, there are plural subjects of emotions. This neither entials, nor is entailed by, the claim that there are aggregate subjects of emotions.

Why is Gilbert tentatively on both sides? Let’s take a look ...

Recall that Gilbert’s analysis of joint commitment has two parts.

Gilbert on joint commitment

[1] The subject:

‘a commitment

by two or more people

of the same two or more people.’

Here I interpret Gilbert as saying that the commitment is something we collectively have. By comparison, consider our being collectively obliged to mitigate the effects of global warming. None of us are individually obliged to do this (how could we?), but collectively we are.

Plural subject

-- some individuals who collectively have an attitude.

Aggregate subject

-- a subject with multiple parts that are subjects.

Identical to the individuals.

Distinct from the individuals.

When we have plural subjects, there is nothing distinct from the subjects which is the subject of the predication. The plural subject is identical to the individuals.

But when we have aggregate subjects, there is something distinct. The individuals \emph{comprise} the aggregate subject but the aggregate subject is not \emph{identical} to those individuals.

This is potentially confusing because the aggregate subject might be nothing but an aggregate of the individuals who are the plural subject.

Could not involve other individuals.

May involve other individuals.

Still we know they are different because different counterfactuls are true of the plural subject and of the aggregate subject.

To illustrate, the man o’ war is nothing but the polyps, but the man o’ war can surive the loss of one polyp and the addition of another whereas the polyps can’t (they aren’t *these* polyps anymore if there is one missing or one addded).)

True: Collectively form an aggregate subject.

False: Does not form an aggregate subject.

Even where there is a plural subject and an aggregate subject and the componets of the aggregate subject are the plural subject, still different things can be true of the aggregate subject and of the plural subject

For example, he animals that comprise an aggregate animal do collectively comprise an aggregate animal; but the aggregate animal itself does not comprise an aggregate animal.

False: Do not collectively sting or eat. [?]

True: Does sting and eat.

For example, an aggregate animal, the Portuguese man o' war (Physalia physalis), stings and eats but the animals (polyps) that compose it do not collectively sting or eat.

Gilbert, Schmid

Pettit, List, Helm, ?Gilbert

The philosophers whose current focus is plural subjects or aggregate subjects.

Note the contrast between e.g. Pettit (aggregate subject) and Schmid (plural subject) According to Schmid, ‘Feelings can indeed be shared in the simplest sense of the word,’ the sense in which ‘sharing is not a matter of type, or of qualitative identity (i.e. of having different things that are somehow similar), but a matter of token, or numerical identity’ (2009, p. 88). On Schmid’s view, there are plural subjects of emotions. This neither entials, nor is entailed by, the claim that there are aggregate subjects of emotions.

So that is why Gilbert is tentatively on both sides.

We have seen aggregate actions, and even aggregate preferences.

But how do we get from here to aggregate *intentions*?

These are the questions you would want to answer if you were going to pursue team reasoning.

1. What is team reasoning? ✓

2. [background] aggregate agents ✓

3. How might team reasoning be used in constructing a theory of shared intention? ✓

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Three Strategies: Plural, Aggregate and Reductive

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