Group Knowledge, Questions, and the Division of Epistemic Labour

Abstract

Discussions of group knowledge typically focus on whether a group’s knowledge that p reduces to group members’ knowledge that p. Drawing on the cumulative reading of collective knowledge ascriptions and considerations about the importance of the division of epistemic labour, I argue for what I call the Fragmented Knowledge account, which allows for more complex relations between individual and collective knowledge. According to this account, a group can know an answer to a question in virtue of members of the group knowing parts of that answer, when the whole answer is available to group-level action. I argue that this account explains a swathe of central cases of group knowledge, as well as explaining some central features of group knowledge.

1. Introduction

What is the relationship between the knowledge had by a group, and the knowledge had by people who make up a group? Recent debates in social epistemology have focused on the question of whether a group’s knowing something requires some member of that group knowing or believing it.[1] This debate assumes that if there is an interesting relation between individual and group knowledge, it holds between individual and group-level attitudes to the same proposition.

In this paper, I develop an account of group knowledge that allows for a more complicated relation between individual and group knowledge. This picture is motivated by consideration of cases involving the division of epistemic labour, whereby a group deals with a complex body of information by dividing it into parts and assigning those parts to different members.[2] This account involves two ideas: i) that a group can know an answer to a question in virtue of its members knowing various parts of that answer, and ii) that group knowledge requires that what is known is accessible to collective action. The full account combines distributed knowledge of the parts of an answer to a question with a requirement that this knowledge is accessible to group-level action, giving us the following account of group knowledge:

I intend this account as a sufficient condition for group knowledge, but I don’t want commit to the corresponding necessity claim. Group mentality and our talk and thought about collective entities are complex topics, and there may well be several different ways in which we might explicate the concept of group knowledge (de Ridder 2019) which might be useful for different purposes, or for different kinds of groups. In part, my project is ameliorative: I hope to make the case that the Fragmented Knowledge account provides a productive and useful way to think about the epistemic lives of various different kinds of groups.[4] In particular, I argue that this account is well-suited for making sense of the knowledge had by groups with developed internal structures and procedures,[5] that it makes sense of the way we use collective knowledge ascriptions to explain and predict collective actions, and that it makes plausible predictions about the epistemic permissibility of collective actions and intentions.

The plan of action is as follows. In Section 2 I lay out the several cases of the division of epistemic labour, and in Section 3 I argue that none of the established accounts of group knowledge can make sense of these cases. In Section 4 I lay out a framework for thinking about questions, focusing on their part-whole structure, and in Section 5 I show how tools from this framework help us to think about the division of epistemic labour. In Section 6, I use these tools to formulate the Fragmented Knowledge account, starting with a simple account that looks to individuals’ partial knowledge, before motivating the requirement that the answer proposition derived from individual knowledge be available to collective action. In closing we consider some upshots of the account and respond to some potential worries.

A couple of clarificatory points.

For presentational purposes I will be assuming that both knowledge-wh, and knowledge-how involve knowing propositions. There is a lively debate about the propositionality of knowledge-wh and knowledge-how (Bengson & Moffett 2011b; Cath 2019; Fantl 2008; Parent 2014). Although a propositional picture of knowledge-wh has fairly wide support, a propositional picture of knowledge-how is extremely controversial. Taking on the assumption of propositionality massively simplifies our presentation, allowing us to use the same machinery to make sense of the division of labour involved in knowledge-that, knowledge-wh, and knowledge-how. However, this assumption is not required for the success of the Fragmented Knowledge account. The central claim of this account concerns the relation between individual and group-level knowledge, meaning that it is neutral on how to understand individual knowledge. The core idea of this account is that a group can know something in virtue of its members knowing the parts of that thing. This idea can be filled out in different ways depending on how we understand knowledge, the kinds of things that we can know, and the different kinds of part-whole structures had by the objects of knowledge.[6]

The inspiration for the Fragmented Knowledge account comes from discussions of what linguists call the cumulative—or sometimes the semi-distributive—reading of collective knowledge-wh ascriptions. In fact, our first pass at an account of collective knowledge (FRAGMENTED KNOWLEDGE 1) is extremely close to Uptal Lahiri’s (2002: C4) semantics for this reading. The fact that the account takes inspiration from formal semantics raises the difficult question of the proper relation between ontology and formal semantics. This question has been discussed both in relation to knowledge-how (Devitt 2011; Glick 2011; Noë 2005; Stanley 2011; Stanley & Williamson 2001), and social ontology (Ritchie 2016; in press). Some authors seem to treat linguistic evidence as providing conclusive answers to philosophical questions, taking what Devitt (2011) calls a linguistics-first approach. We don’t need to rely on this methodology to make use of linguistic evidence in philosophy. The Fragmented Knowledge account certainly takes inspiration from semantics, but I think that it should be assessed on the basis of both linguistic and philosophical considerations.[7]

2. The Division of Epistemic Labour

In this section, I set out three cases in which a group possesses knowledge in virtue of knowledge distributed among its members.[8] These are divergence cases, in the sense that the groups in these examples each know propositions which none of their members do. The three cases I consider cover different kinds of knowledge (how, wh, and that) and, as we shall see in Section 5, provide examples of different ways in which answers to sub-questions can combine.

Our first case comes from Bird (2010: 33–34) with some details added:

In this case, sentences 1) and 2) both seem true:

• 1) NASA knows how to make a space shuttle.
• 2) No-one in NASA knows how to make a space shuttle.

This pair of judgements is intuitively plausible and is backed up by surveys of non-philosophers’ intuitions (Jenkins, Dodell-Feder, Saxe, & Knobe 2014).[9]

Our second case involves knowledge-who:

This case supports a similar pair of divergent judgements, expressed by 3) and 4):

• 3) The Rowing Club knows who came to the party.
• 4) None of the members of the Rowing Club knows who came to the party.

Our third case is adapted from an example that comes from Roger Schwartzschild via Uptal Lahiri (2002: 189–190), and involves both knowledge-whether and knowledge-that:

In this case, we can formulate divergence judgements using both knowledge-whether and knowledge-that. Consider the following pairs of sentences uttered at a time between the information having been gathered and everyone reporting their results (by which time everyone would know that the path was litter-free):

• 5) The scouts know whether the whole path is litter-free.
• 6) None of the scouts knows whether the whole path is litter free.

• 7) The scouts know that the path is litter-free.
• 8) None of the scouts know that the whole path is litter-free.[10]

As a group, the scouts seem to have knowledge-whether and knowledge-that which goes beyond that possessed by any individual scout.

I suggest that we should take the divergence judgements in NASA, PARTY, and LITTER seriously. Although we do sometimes mistakenly ascribe knowledge to groups when the groups are really just in a position to know the propositions in question (Lackey 2014: 294–295), considerations of the explanatory and normative role of knowledge supports the claim that these are genuine cases of collective knowledge.

Sentences 1), 3), 5), and 7) predict and explain the actions of the groups in the ways distinctive of knowledge in the individual case. We might appeal to NASA’s know-how to predict that it will successfully make a shuttle, or appeal to the scout group’s knowledge about whether the path is litter free to predict whether it will keep scouring the path. These sentences can also be used to flag the respective groups as informants (Craig 1990). If the police were rounding up partygoers, it would be natural for a police officer to say:

• 9) Let’s get the Rowing Club in; they know who came to the party.

The ascriptions of knowledge to the groups also predict the appropriateness of collective action, assertion, and intention (Habgood-Coote 2018a; Hawthorne & Stanley 2008; Williamson 2000). NASA could rationally form an intention to make a space shuttle, the Rowing Club would be acting with epistemic propriety if it gave a statement about who was at the party that drew on its members’ knowledge, and the scout group would be acting with epistemic propriety if it claimed the council reward for having a litter-free cycle path on the basis of its members’ knowledge.[11]

It is also difficult to take issue with the denial of knowledge to the members of the groups. In NASA we can truly say things like ‘the chemist knows how to make a space shuttle,’ but only in a sense that expresses very coarse-grained and general knowledge (you have to build the fuselage, make fuel, and program the computers) which falls far short of the practical knowledge which we are supposing is possessed by the group.[12] If we focus on the relatively demanding readings of the knowledge ascribed to the groups, it should be clear that the members of the group do not know what the group does.

What lessons might we draw from these cases?

The modest lesson is that these cases demonstrate the importance of what linguists call the cumulative reading of group knowledge ascriptions. Whereas a distributive reading of a predicate ascribes a property to each of the members of the group, and a collective reading ascribes the predicate to the group collectively, the cumulative reading claims that the members of the group contribute to the collective fulfilling the predicate such that between them the predicate fully obtains.[13] When linguists discuss sentences like 1), 3), 5), and 7) they seem to have the modest lesson in mind.

The ambitious lesson is that these cases instantiate an important feature of collective knowledge: the division of epistemic labour.[14] A central feature of collective agents is their ability to deal with complex tasks by splitting them into simpler tasks that can be performed more efficiently by individuals with the appropriate skills. For example, NASA can deal with the task of making a space shuttle by splitting it up into simpler tasks like making the fuselage and concocting the fuel. We might think this division of labour carries across into the epistemic realm, and that the cumulative reading of knowledge ascriptions picks out the kind of knowledge which is its consequence. This point is easiest to see in the case of collective inquiry: a collective agent can perform the task of coming to know something by different members coming to know suitably related smaller things.

If we draw the modest lesson, what we want is an account of the kind of knowledge picked out by the cumulative reading of collective knowledge ascriptions, which we can treat as a linguistic curio. By contrast, if we draw the ambitious lesson, these cases demonstrate an important structural feature of collective knowledge which we will want to build into our account. I will draw the ambitious lesson, but if for some reason the general account of group knowledge turns out to be incorrect, then what I say below can be repurposed as an account of the cumulative reading of group knowledge ascriptions.

3. Explaining the Division of Labour

There are various accounts of group knowledge available in the literature. In this section I argue that none of them can offer an explanation of the division of epistemic labour exhibited in cases like NASA, PARTY, and LITTER.

A central question for accounts of group knowledge is whether they endorse the following principle:

Following convention, we can call accounts that endorse SUM_KNOW Summativist, and accounts that deny it Non-Summativist.[15]

Summativist accounts cannot explain the presence of group knowledge in NASA, PARTY, and LITTER. These are cases in which a group knows something which no member of the group knows. In fact, we could easily tweak NASA, PARTY, and LITTER so that no member of the group had any attitude toward the proposition known by the group. It wouldn’t be particularly odd if the members of NASA had simply never considered how to make a space shuttle, having no view on the matter.

We can divide up non-Summativist accounts by considering which part of the knowledge is located at the collective level. This gives us the following menu of views to consider:

1. Group knowledge involves collective belief (Wray 2007);
2. Group knowledge involves collective justification (de Ridder 2014; Lackey 2016);
3. Group knowledge involves group-level reliability (List 2005);
4. Group knowledge involves group-level realisation of functional properties (Bird 2010).

None of these accounts has a satisfying explanation of these cases.

Wray (2007) appeals to Margaret Gilbert’s (1987) account of group belief, suggesting that the collective element of group knowledge is a joint commitment to the proposition known (although he argues that we should think of joint commitments as acceptances, not beliefs, see Wray 2001). This account can’t handle NASA, PARTY, and LITTER, because the members of the groups in these cases need{~?~R: In those cases?}{~?~JH: yup}{~?~JH: On the footnote deletion. I get in trouble with questions, because when I have a italicised phrase, the ‘?’ isn’t functioning as straightforward punctuation – rather it’s part of a noun phrase to indicate that the noun phrase is a question not a proposition. I think it’s fine to delete the extra full stop, but just to note that question marks are functioning a bit weirdly in lots of places.} not be jointly committed to the propositions known by the group. As individuals, the members of NASA might not have any commitments about the best way to make a space shuttle. Although the rowing club and scouts might jointly commit to propositions after having shared their distributed information, these groups know the propositions in question before they pool their knowledge.

De Ridder (2014) argues that scientific knowledge is a collective property because scientific knowledge requires access to reasons for the reliability of belief-forming processes, and in contemporary science this understanding is often distributed between the specialists in a research team. Although this may be a plausible picture of what occurs in some cases of collective scientific knowledge, this diagnosis doesn’t fit well with NASA, PARTY, and LITTER. These are cases in which the object of knowledge—rather than the reasons justifying it—is distributed between the members of the group.[16]

Lackey’s (2016) group epistemic agent account of justified belief claims that a group justifiedly believes some proposition when it is believed by a significant number of operative members of the group, the bases of individual beliefs in that proposition are coherent, and a rational process of deliberation would lead to a belief set which still supported that proposition. Although this is an account of justified belief, rather than knowledge, it is worth considering whether it can be put to work here. The problem lies in the first condition: in NASA, PARTY, and LITTER no member of the group has a justified belief about the proposition known by the group, meaning that Lackey’s account predicts that none of these cases involve collective justified belief.

List (2005) develops a judgement aggregation approach to group knowledge. The core idea of this approach is that a group’s institutional structure will determine an aggregation function that takes as inputs a profile of individual beliefs and outputs a collective position for that group (see List & Pettit 2011). We can assess whether a group’s collective position constitutes knowledge by considering how reliable the outputs of the aggregation function are, which will be a function of both individual reliability and the reliability of the aggregation function. List (2005: 29) considers an aggregation function tailor-made for situations involving a division of labour: the distributed premise-based procedure. This function splits a group into sub-groups whose attitudes determine the group’s attitude on premises which are then combined to yield a collective position on the conclusion (see also List & Pettit 2011: C4). The problem with applying the judgement aggregation approach to understand distributed knowledge is that a group can possess distributed knowledge, even if its institutional structure fails to implement the right aggregation function to exploit this knowledge. Goldman (2004) cites an exchange from the 9/11 commission hearings which illustrates the way a group’s aggregation function can diverge from its knowledge. Commenting on why the FBI did not internally share information about the 9/11 perpetrators’ flight training, former national security advisor Samuel Berger made the following Rumsfeldian pronouncement:

The force of this remark is that although the FBI’s aggregation function was faulty—meaning that it was not able reach the right position about whether the perpetrators were a threat—the distributed knowledge possessed by FBI members still qualifies the group as having collective knowledge about this question.[18]

Bird (2010) pursues an analogical strategy, exploiting the idea that individual and collective knowledge will have the same functional properties. He argues that the characteristic properties of group knowledge are that it i) is produced by a social process which produces propositional outputs, ii) involves truth-filtering mechanisms, and iii) yields outputs which are available to social action and other social information-filtering processes.[19] On this account, group knowledge is a state which lies causally downstream of social information-filtering processes, and which can at least potentially feed into other social processes. Fagan (2012) helpfully distinguishes between three senses of collective knowledge: knowledge that is collectively produced, knowledge involving a collective agent, and knowledge involving a collective content. Bird’s account is well-suited to explain cases of collective production of knowledge, but it fails to generalise to all cases of knowledge involving a collective agent.[20] In the cases under consideration the groups’ knowledge need not be the output of a social information-filtering process. NASA might have assembled a group of people with the appropriate specialised knowledge, and it would still wind up knowing how to make a space shuttle.

Given the failure of extant accounts to make sense of NASA, PARTY, and LITTER, we will need to look elsewhere for an account of the division of epistemic labour. In the next section, I will gather the tools we need to think about these cases, before applying these tools in Section 5.

4. The Mereology of Questions

Following Lahiri (2002: 188), I think that the right way to understand the cumulative reading of sentences like 1), 3), 5), and 7) is to think of them as ascribing partial knowledge to members of the group that adds up to a resolving answer to the question.[21] To develop this idea, we will need some tools from the semantics of interrogatives. In particular, we need to understand: i) what questions are, and how they relate to answers ii) partial knowledge-wh, iii) what it is for one question to be part of another, and iv) the different ways in which the answers to several smaller questions can combine to resolve a bigger question. The subsections that follow address these questions in turn.

4.3. Subquestions

Another payoff of the partition approach is that it gives us a clear account of what it is for one question to be part of another (see Roberts 2004; 2012).

We can make a first pass at understanding question-parthood by saying that one question is part of another when it divides up the same portion of logical space, but with a smaller number of more coarse-grained cells. Consider the question who came to the party?. Assuming a domain of just A and B, this question gives us the following partition of four cells (where ‘A’ stands for A came to the party, and ‘a’ stands for A didn’t come to the party):

Figure 1.

Who came to the party?

Although this partition contains relatively few cells, it is easy to see that there are various coarse-grained ways to partition up the space. For example, we could ask did A come? giving us the set {A came; A didn’t come}. Or we could ask did anyone come? dividing up logical space into {someone came; no-one came}.

Figure 2.

Did A come to the party?

Figure 3.

Did anyone come to the party?

We can say that both these new questions are subquestions of the old question who came to the party? in the sense that they are part of the old question. Let’s introduce the strict subquestion relation to pick out the parthood relation that involves only coarsening the partition. We can give a precise definition of this relation in terms of entailment relations between the answers to the question and its subquestions:

STRICT: Q1 is a strict subquestion of Q2 iff a complete answer to Q1 entails a partial answer to Q2.[32]

The notion of parthood picked out by STRICT is useful, but does not cover all the interesting cases. The question if there was beer at the party, did A come? is not a strict subquestion of who came to the party?. Neither there was beer at the party, nor there was not beer at the party allow us to rule out any of the cells in the initial question. However, if we want to use the notion of a subquestion to pick out the kinds of questions we can use to build a resolving answer, this kind of question certainly seems to be of interest. One way to include questions like if there was beer at the party, did A come? within the subquestion relation is to relax the notion of entailment in our definition to allow entailment of answers against a background of accessible information. We can call this kind of subquestion a casual subquestion:

CASUAL: Q1 is a casual subquestion of Q2 iff a complete answer to Q1, together with accessible information, entails a partial answer to Q2.

If there was beer at the party, did A come? is a casual subquestion of who came to the party? because an answer to the former question, together with the accessible information that there was beer at the party provides a partial answer to the question of who came to the party.

This move closely parallels Robert’s (2004: 210; 2012: 6.11–12, 6.19–20) appeal to contextual entailments. However, whereas she appeals to information that is already in the context, I am appealing to accessible information: information which agents either have, or could obtain given their epistemic situation and capacities. Exactly what counts as accessible is a complex matter, and the fact that information is accessible does not mean that it is easy to get hold of.

Strict subquestions are always simpler than the original question, but casual subquestions can be more complex. In the right context, what food was served at the party? might be a subquestion of who came to the party?, but if the culinary possibilities in a context are richer than the potential guests, the subquestion will have more complete answers than the original question. Although questions with only two answers—such as whether questions and polar questions—have no strict subquestions, they can have casual subquestions. Was there beer at the party? and what food was served at the party? might both be casual subquestions of whether A came to the party?

Below ‘subquestion’ will refer to both the strict and the casual notions, and we will need both notions to explain the division of epistemic labour.

5. Subquestions and the Division of Epistemic Labour

With these tools from the semantics of interrogatives in hand, we can explain how the groups in NASA, PARTY, and LITTER can have collective knowledge in virtue of the knowledge distributed between their members.

Let’s start with PARTY, since mention-all readings involve the most straightforward way of partial answers adding up to a resolving answer. We are aiming to explain the truth of the following sentence:

• 3) The Rowing Club knows who came to the party.

Assuming that the interrogative who came to the party? takes a mention-all reading, meaning that a resolving answer is a complete list of exactly who came to the party. None of the members of the Rowing Club is in possession of such an answer. Each member of the club only knows a partial list corresponding to a partial answer, meaning that they each have partial knowledge-wh. Crucially, putting these partial lists together yields a complete list of who came. To put this point in terms of partial answers: putting their mention-some answers together would yield a resolving complete answer which ruled out all of the possible combinations of people that might have come, except the set of people that in fact came to the party.

A slight wrinkle emerges when we notice that who came to the party? might take the strongly exhaustive reading associated with complete answers, requiring not just the complete set of people that came, but also the information that no-one else came. Until they put their heads together, none of the members of the Rowing Club knows that any list of party-goers is the complete answer (although they might know that the combined list would be a resolving answer). We might worry that if the interrogative takes an exhaustive reading, the members of the Rowing Club do not have a resolving answer between them. There are two options here. We might take 3) to express a non-exhaustive mention-all reading, meaning that a resolving answer requires only the complete set of positive minimal answers. Alternatively, we could say that the Rowing Club really does collectively know the answer to the question with a strongly exhaustive reading, because although the exhaustivity information is not known by any individual, it would become available after pooling. I think that the first line is more plausible, allowing us to say both that the group knows who came to the party (on the non-exhaustive mention-all reading), and that it stands to gain something by collating its members’ knowledge.

In NASA, we are interested in the following sentence:

In this case we want to combine individual pieces of knowledge to yield a mention-some answer to the question how to make a space shuttle?. A complete answer to a how-to question will be an exhaustive set of complete methods (i.e. a complete negative and positive assignment of is a way to make a space shuttle to all ways in the domain). This kind of answer is extremely demanding, and for most purposes a resolving answer will be one that provides one complete method for the task at hand. With how to V? questions, the relevant kind of partial answers will usually be ones that specify a method for a sub-task of the activity of V-ing: in this case methods for the various sub-tasks involved in making a space shuttle. A sub-task specifying partial answer provides us with a method for performing that sub-task. This allows us to rule out the all the possible complete answers to the question which do not contain a complete method involving the relevant method for performing the sub-task. A set of sub-task partial answers can combine to yield a resolving answer to the question, when the methods for performing the various subtasks combine to provide a complete method for performing the overall task. This is exactly the structure which we find in the NASA case. Each of the specialists knows how to perform one sub-task, meaning that they each possess a partial answer to how to make a space shuttle?.[34] Putting these partial answers together yields a complete method for building a space shuttle, meaning that the individual-level partial knowledge combines to give group-level knowledge-how.

Finally, let’s consider LITTER. We need to explain the truth of two sentences:

• 5) The scouts know whether the whole path is litter-free.
• 7) The scouts know that the path is litter-free.

Start with 5). Whether-questions are simple {p; not-p} partitions, meaning that there are no partial answers to this kind of question. We cannot add partial modifiers to knowledge-whether, meaning that the following sentence is anomalous:

• 12) #Arabella knows in part whether Jane came to the party.

To make sense of sentence 5) we will need to build up a resolving answer to the question from the answers to its casual subquestions. In LITTER, each of the scouts searched a portion of the path for litter, meaning that by the end of each of their searches they knew whether there was any litter on their assigned stretch. The question whether stretch A is litter-free? is a casual subquestion of whether the whole path is litter-free? because an answer to the former question, when combined with a body of accessible information—in particular, information about whether all of the other stretches of the path are litter free—will entail an answer to the latter question. So, in this case, all of the scouts know answers to casual subquestions of whether the whole path is litter-free?, which are such that when the answers to these questions are combined together, they entail a complete answer to the question of whether the path is litter free.

This leaves us with the collective knowledge-that ascription in 7). A knowledge-that ascription does not semantically express any question, but we can take a parallel approach to this kind of case by considering this proposition against the background of a question supplied by context. A fairly natural move here is to appeal to the question under discussion in the attributor’s conversational context (Roberts 2012) and take the that-clause to express an answer relative to that question (see Schaffer 2007; 2008). For example, when we utter sentence 7) thinking about the scenario described in LITTER we are presumably interested in the question whether the path is litter-free? meaning that we are thinking of the proposition that the path is litter-free as an answer to that question.[35] With this contextually supplied question in place, we can repeat the story about how the answer the path is litter-free was constructed from answers to casual subquestions like whether stretch A is litter-free?.[36]

6. Fragmented Knowledge

The Fragmented Knowledge account involves two kinds of conditions: individual-level conditions concerning the knowledge of group members, and group-level conditions concerning what propositions the group is disposed to act on. So fact, we’ve motivated the first condition, but we need to see what work the second condition does. Let’s start off by considering an account which takes the first kind of condition to be sufficient for collective knowledge in order to motivate the need for the second condition (section 6.1). I will then formulate the second condition and present the full account (section 6.2), before considering some upshots of the account. We will consider the Fragmented Knowledge view’s commitment to contextualism about collective knowledge ascriptions (section 6.3), an analogy with the JTB theory of knowledge (section 6.4), how the account might be adjusted to account for non-propositional accounts of knowledge-wh (section 6.5), how the account fits into the debate between Summativists and non-Summativists (section 6.6), and how it handles knowledge-action connections, and group defeat (section 6.7).

7. Conclusion

Philosophical discussions about group knowledge have proceeded on the assumption that if there is an interesting relation between individual and group knowledge, it must be at the level of individual propositions. In this paper I have tried to shake this assumption, considering cases of the division of epistemic labour in which a group knows some body of information when the members of the group know various different parts of that body of information. I have argued that cases of the division of labour can be understood by appealing to the mereological structure of questions and have proposed the Fragmented Knowledge account to explain the kind of knowledge present in these cases. Although I have stopped short of proposing that FRAGMENTED KNOWLEDGE 2 is the only way to think about collective knowledge, I think that it explains a swathe of central cases, and sheds light on some important features of group knowledge, and collective mentality more generally.

To close, I want to note some ways in which the framework developed in this paper can be extended. First, the approach of using questions and subquestions to think about the epistemic state of a group could be extended to develop accounts of collective justification, belief, and ignorance as we saw in Section 6.4. Generalising further, we might use a question-focused account to make sense of group inquiry and the collective production of knowledge. Secondly, the Fragmented knowledge account might be used to help us to think about epistemic principles of group design. If group knowledge is a matter of individual knowledge being available to collective action, then maximising collective knowledge involves combining mechanisms that access individual knowledge with those that facilitate collective action. Thirdly, although we’ve focused on relatively small and well-structured groups, the account might be scaled up to think about larger groups. This might be useful as part of a project of demystifying political and scientific knowledge by revealing them as involving massively distributed knowledge.

Acknowledgements

Thanks to two reviewers and an editor at this journal, Alexander Bird, Jessica Brown, Josh Dever, Jeroen de Ridder, Miguel Egler, Keith Harris, Katherine Hawley, Megan Hyska, Bruno Jacinto, Matthew McGrath, Richard Pettigrew, Brian Weatherson, Fenner Tanswell, Caroline Touborg and an audience in St Andrews. Special thanks to James Andow for help with the statistical tests in Footnote 9, and to Jessica Brown for suggesting QUARTET.

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Notes

1. See Hardwig (1985), Kitcher (1991), Thagard (1997), Tuomela (2004), List (2005), Wray (2007), Rolin (2007), Bird (2010; 2014), Fagan (2011; 2012; 2014), de Ridder (2014), Lackey (2014), Miller (2015), Klausen (2015).

2. For classic discussions of the division of practical labour, see Smith (1776/1982) and Durkheim (1893/2014). Modern literature typically uses the phrase ‘the division of epistemic labour’ to refer to a Smithian phenomenon of scientific competition (Kitcher 1990; Strevens 2003; Weisberg 2010; Weisberg & Muldoon 2009; Zollman 2010), or to refer to a kind of epistemic dependence (Goldberg 2011). I will use the phrase to refer to the phenomenon in Smith’s original example: co-operation within a team with diverse skills (see Muldoon 2017).

3. See Boddy (2014), Baltag, Boddy, and Smets (2018) for discussions of group knowledge that employ similar formal tools.

4. Throughout, ‘group’ and ‘collective’ will be used equivalently as umbrella terms for any agent partly or completely composed of individual agents.

5. In Section 6.4 I will consider unstructured groups, suggesting that although they cannot have fully-fledged collective knowledge, they can have collective propositional justification.

6. See Section 6.6 for a discussion of how this account might be tweaked for a non-propositional account of knowledge-how.

7. For an argument for this attitude toward linguistic evidence in the knowledge-how debate, see Habgood-Coote (2018b).

8. For cases with similar structures, see Tollefsen’s UN population case (Tollefsen 2007; Lackey 2012; 2014), Bird’s interdisciplinary modus ponens case (Bird 2010: 34–35), Hutchins’s (1995) discussion of the USS Palau, Knorr Cetina’s (1999) discussion of the high-energy physics community, and the cases of radical collaboration in Kukla (2012), Winsberg, Huebner, and Kukla (2014), Huebner, Kukla, and Winsberg (2017).

9. Jenkins et al (2014) presented 116 participants with a case like NASA, and considered whether participants ascribed knowledge to the group, and to its members. Although they don’t report results specifically for this case, we can isolate responses to this case, and run the same tests as they do. A one-way ANOVA revealed a significant effect of question condition on responses for this single case, F(2, 115) = 97.81, p <.001, η² = .63. Tukey’s posthoc tests showed that on a 1 to 7 scale (1 low, 7 high) participants agreed more with ascriptions in the group-level condition (condition two, which is equivalent to sentence 1) (M = 6.48, SD = 1.24) than in either the ‘each member’ question condition (condition three) (M = 1.68, SD = 1.19), p < .001, or the ‘any member’ question condition (condition one, which is equivalent to the negation of sentence 2) (M = 3.10, SD = 2.07), p < .001. This suggests that in cases like NASA the folk are willing to ascribe knowledge to the group, while not ascribing knowledge to its members.

10. One might take issue with the claim that the scouts know whether the path was litter free before they share their results. Until the results are announced, we might think that the group is merely in a position to know whether the path was litter-free (Lackey 2014). One might motivate this move by arguing group knowledge requires some kind of joint commitment to the proposition in question. Although there might be a perfectly good sense of collective knowledge has this requirement, the considerations about the explanatory and predictive roles of knowledge ascriptions below suggest that there is also a good sense in which the group does know the answer to this question before its members pool their results.

11. For the significance of the qualifications about the basis of action, see Section 6.7.

12. We get a similar phenomenon if we focus on the mention-some reading of ‘who came to the party’ in 4).

13. To get a grip on the cumulative reading, consider:

    1') Four linguists wrote three books.

    On the collective reading, the four linguists jointly wrote three books. On the distributive reading, each of the four linguists wrote three books. On the cumulative reading, there is some way to combine the linguists as authors or co-authors such that between them the number of books that they wrote is three (say, if three co-wrote one book, and the other the other two). For discussion of this reading in linguistics, see Scha (1981), Landman (1989), Gillon (1992), Schwarzschild (1996), Lahiri (2002: 184–220), and for discussions in philosophy see Dever (1991), Oliver and Smiley (2008), Linnebo and Nicolas (2008), Cotnoir (2013: 308–311), Ludwig (2016: ch. 10 note 25).

14. To make things simpler, I have focused on cases where the division of labour is formalized by the group’s organizational structure. Cases where a division of labour is implemented in a less formal way—think of the invisible hand of the market (Hayek 1945), competition in science (Strevens 2003), or the contingencies of social position (Collins 2000)—will be much more complicated. These cases will potentially run afoul of the accessibility to collective action condition—presumably the invisible hand acts only in a metaphorical sense—but we can still use the machinery of questions and subquestions to think about the epistemic potential of these groups (see Section 6.4).

15. The question of whether SUM_KNOW holds is often associated with whether group knowledge is reducible to individual knowledge. The reducibility of group knowledge is orthogonal to the truth of SUM_KNOW. One might endorse SUM_KNOW and deny the reduction of group to individual knowledge. For example, one might hold a mixed view that claims that both individual knowledge and some group-level phenomenon is necessary for collective knowledge (See (Lackey 2016) for an account of group justified belief with this structure). One might also deny SUM_KNOW whilst endorsing the reduction. For example, one might claim that group knowledge reduces to some individual-level attitude other than knowledge that p. These points generalise to other group attitudes, meaning we should sharply distinguish between the questions of whether Summativism is true, and the question of whether group attitudes are reducible to individual attitudes.

16. Note that the supporter of the Fragmented Knowledge account can treat de Ridder’s cases as involving fragmented knowledge of the answer to the question why is this process reliable?

17. Full transcript: http://www.washingtonpost.com/wp-dyn/articles/A20349-2004Mar24.html??noredirect=on

18. To muddy the waters, we can read ‘the FBI didn’t know what it did know’ in two ways. The first reading is a denial of higher-order collective knowledge (i.e., the FBI was ignorant about the question of what it knew). The second reading is effectively a contradiction test exploiting the ambiguity of ‘knows’ (Zwicky & Sadock 1975: 4). We can get fix this reading by using the following focus pattern: ‘the FBI didn’t [know]_f what it did know’ (i.e., the FBI knew, but it didn’t really know). We are interested in the first reading, according to which the FBI’s higher-order ignorance prevented it from acting on its knowledge.

19. Although I am skeptical of conditions i) and ii) in Bird’s account, the availability condition FK3 in FRAGMENTED KNOWLEDGE 2 is pretty close to iii).

20. Bird’s central interest is in groups that manifest Durkheimian organic unity (see Bird 2014), suggesting that his account should be understood as an account of group knowledge for groups characterised by organic unity. Thus restricted, the worry for his account is that groups with a relevant organic unity—such as NASA—can come to know without undergoing a social process of learning.

21. For a similar idea, see Hardwig (1985: 349). For the details of Lahiri’s semantics for the cumulative reading, see Lahiri (2002: C4), and for an alternative treatment which appeals to quantification over the parts of questions, see (Beck & Sharvitt 2002: 149–52). Note that following Schwarzschild, Lahiri connects the cumulative reading to sentences involving verbs connecting two grammatically plural terms. This means that his account does not neatly carry over to sentences like 1) and 3) which involve grammatically singular noun phrases denoting a group agent (i.e., ‘NASA’, and ‘the Rowing Club’).

22. We will need to complicate the picture to deal with interrogatives with multiple wh-words, ‘whether’ interrogatives, and interrogatives with no question-words.

23. The distinctions we need would be rather difficult to draw in the alternative semantics proposed by Hamblin (1973) or Karttunen (1977). I think it would be possible to reconstruct them within an inquisitive semantics framework (Ciardelli, Groenendijk, & Roelofsen 2015; 2018), but this would considerably complicate the presentation.

24. A complete answer will also be a mention-some answer, a mention-some answer will also be a partial answer, and a mention-some answer will either be or entail a positive minimal answer. Often, I will be implicitly adding a ‘mere’ before ‘partial answer’.

25. On the context-sensitivity of the answerhood relation, see Boër and Lycan (1986).

26. It is somewhat of an idealisation to think that context always fixes which kind of answer is required. Does context always fix whether a mention-some or mention-all reading of an interrogative is intended, or fix a relevant domain of quantification? This means that some knowledge-wh ascriptions (including to groups) will have an indeterminate meaning.

27. Some examples with different verbs, adverbs, and question-words:

    1'') Dale has worked out in part how to make the wardrobe

    2'') Patricia learnt for the most part who was at the party.

    3'') John knows to some extent where the lost pages are.

    This kind of gradability has been discussed in linguistics under the heading of Quantificational Variability Effects (QVE). See Berman (1991), Groenendijk and Stokhof (1993), Williams (2000), Lahiri (2002: chs. 2 and 5), Beck and Sharvitt (2002). For a philosophically illuminating application of some of these ideas to the debates about the gradability of ‘knows-how’ ascriptions and the unity of knowledge, see Pavese (2017), and Pavese (2015) respectively. Knowledge-wh ascriptions can also be modified by qualitative predicates, such as:

    4'') Raimo knows how to swim really well.

    These predicates seem to modify the entities expressed by the wh-word. What is good is the way of swimming that Raimo knows how to perform (Pavese 2017).

28. Because this kind of gradability involves modification of the interrogative complement rather than the verb, it is compatible with the claim that ‘knows’ is not a gradable verb (Pavese 2017; Stanley 2005).

29. There is considerable discussion about how to understand QVE. Accounts have been proposed that appeal to quantification is over i) the objects which the wh-word ranges over (Berman 1991), ii) propositional answers to the question (Lahiri 2002), iii) subquestions of the superquestion (Beck & Sharvitt 2002), and iv) question-proposition pairs (Pavese 2017).

30. For defences of contextualism about knowledge-wh, see Boër and Lycan (1986), DeRose (2009: ch. 2 appendix), Masto (2010), Parent (2014). For a criticism appealing to warranted assertibility see Braun (2006; see also Hawley 2003). Strength of answer is just one of several kinds of context dependence involved in knowledge-wh ascriptions. The semantic content of interrogatives will probably also be affected by the domain of quantification (Stanley 2011: 56–58, 118), modulation of the predicate expressed by the question abstract, and the salient method of identification (Aloni 2008). Infinitival interrogatives will also involve context-sensitive modals (Bhatt 2006; Stanley 2011: 126), contextual resolution of the reference of PRO (Stanley 2011: C3), and may involve an unpronounced task variables (Hawley 2003: 21–22).

31. This account is slightly oversimplified for presentational purposes: strictly speaking it should allow answers to casual subquestions which are not partial answers. See Section 3.3.

32. The strict subquestion relation is equivalent to Groenendijk and Stokhof’s (1984) notion of question-entailment, where Q1 entails Q2 iff every proposition that completely answers Q1 completely answers Q2. A question Q2 is a strict subquestion of Q1 just in case Q1 entails Q2 (Roberts 2012: 6.7).

33. If the question takes an exhaustive reading, then we will also require the conjunction of negative minimal answers.

34. One might worry that a group could have members who know how to perform relevant subtasks, but do not know how to co-ordinate them. The structure of how-to questions rules out this possibility. Both in the individual case and the collective case, merely knowing how to perform subtasks without knowing how to string them together appropriately is insufficient for knowing a resolving answer to the question how to V?. When a task is order-sensitive, merely knowing that the task V-ing involves A-ing, B-ing, and C-ing does not suffice for isolating a resolving answer, say the proposition A-ing, then B-ing, then C-ing is a way to V. One of the subquestions to a how-to question will be the question how should we put the other sub-tasks together?

35. The appeal to questions under discussion is another place where the contextualist bent of the Fragmented Knowledge account shows up. For non-contextualist theories, background questions are a potential source of error. These errors might either be due to pragmatic (Brown 2006; Pritchard 2010; Rysiew 2007) or psychological effects (Dinges 2018; Gerken 2017; Nagel 2010).

36. The information possessed by group members need not add up to a resolving answer to the question under discussion. If the question under discussion was what interesting objects are on the path? and the scouts have only looked for litter, they could still know there is not litter on the path? relative to what interesting objects are on the path?

37. This account (and those below) might also be extended to deal with knowledge of subject matters. Knowledge of subject-matters can involve the division of labour: If each member of the history department knows one of the periods of history from 3,000 BCE to 500 CE, then collectively, the history department knows the period 3,000 BCE to 500 CE. These cases can also be modelled in a partition-based framework. Following Lewis (1988a; 1988b) and Yablo (2014; 2016) we might take subject matters to be partitions (with each cell being a way the relevant portion of the world might be) and take knowledge of a subject-matter to relate an agent to a partition (Yablo 2010) which allows us to model collective knowledge of a subject matter in terms of individuals ruling out different cells in that partition. On the relation between subject-matters and questions, see Szabo (2017).

38. One might worry that this account just reinvents the notion of distributed knowledge familiar from epistemic logic (Fagin, Halpern, Moses, & Vardi 1995; Meyer & van der Hoek 1995). For a discussion of the relation between distributed knowledge and question-sensitive pooling, see Baltag, Boddy and Smets (2018).

39. This worry is closely related to the ‘irrelevant beliefs’ criticism of Summativism about group belief (Gilbert 1989; Schmitt 1994).

40. The task-sensitivity in this condition takes inspiration from Hawley (2003).

41. See Birch (2018) for a narrower conception of group knowledge-how that excludes such cases of prepackaged co-operation.

42. This case is adapted from Schmitt (1994).

43. A special case is the requirement for consensus. If a group’s constitution requires that its members agree on a question before it can act, then the possibility of consensus is a requirement for collective knowledge. If the group’s constitution makes no such requirement, then it is possible for the group to know although they are not in a position to reach consensus.

44. Assuming that anti-austerity campaigns advocate for, and don’t act on behalf of the victims of austerity.

45. The literature on uninvention provides a diverse set of examples of this phenomenon. On the uninvention of nuclear weapons see Mackenzie and Spinardi (1995), and on the uninvention of mathematical proofs see Steingart (2012). Both of these examples involve the loss of knowledge due to the death of relevant individuals. For an example involving uninvention due to deliberate exclusion, see Hicks’s (2017) account of the role of women in early electronic computing in the UK.

46. One caveat: some views about the object of knowledge-how—such as objectualism (Bengson & Moffett 2011a)—aren’t well placed to explain partial knowledge-wh ascriptions (see Pavese 2017), meaning they will struggle to explain the cumulative reading of group knowledge ascriptions.

47. Lackey’s objection targets both cases of the division of epistemic labour and Bird’s (2010: 30–36) publication cases. This response can be used to defend the presence of collective knowledge in both cases, but FRAGMENTED KNOWLEDGE 2 does not predict that the scientific community knows in the publication cases (see Section 6.5).

48. I will set to one side the question of whether the group has collective belief in these cases. If group belief is merely a matter of group-level dispositions (see Section 6.4.) FRAGMENTED KNOWLEDGE 2 can save the connection between group knowledge and group belief.

49. This may be particularly common with collective knowledge-how: in the individual case there are many cases in which knowledge-how is accompanied by false belief. See Wallis (2008: 139–140), Cath (2011), Glick (2011: 409), Brownstein and Michaelson (2016).