How is cultural progress possible? Historically, no other animal has progressed as humans have. Conventional wisdom suggests that by having language, people accumulate knowledge, which produces progress. Such Formal stage 10 wisdom begs fundamental questions. Thus, we assert the cultural necessity of levels of support, or scaffolding, for people to develop higher stages of hierarchical complexity. The resulting, wider accessibility to higher-stage action and knowledge, which requires higher stages of development to understand, enables social and scientific progress. With (...) memes and downward assimilation, larger proportions of society gain access to advanced thinking with support, in turn enabling cultural progress. (shrink)

For as long as there have been theories about common knowledge, they have been exposed to a certain amount of skepticism. Recent more sophisticated arguments question whether agents can acquire common attitudes and whether they are needed in social reasoning. I argue that this skepticism arises from assumptions about practical reasoning that, considered in themselves, are at worst implausible and at best controversial. A proper approach to the acquisition of attitudes and their deployment in decision making leaves room for (...) common attitudes. Postulating them is no worse off than similar idealizations that are usefully made in logic and economics. (shrink)

With closer interactions between academic and commercial entities the role of the university is expanding to also include knowledge transferIn the biomedical and health sciences , close interactions between academic and commercial entities are now common place. Funds from pharmaceutical and biotechnology companies have helped finance major bioscience projects and research centres, graduate students are receiving training in commercial laboratories, and university scientists are translating their ‘intellectual property’ by patenting their research and launching start-up companies. And this is happening (...) with the blessing of universities, who see the commercialisation of research – and the royalties brought in from ‘technology transfer’ – as part of their new mission.The result is that no longer are universities simply places of higher learning, where academics are dedicated to teaching and research, traditionally the ‘first’ and ‘second’ missions of universities; universities now have a ‘third’ mission, to engage in knowledge transfer. Governments and research-intensive industries , are keen to translate university research into marketable products. Facilitated by policies and laws to protect intellectual property rights and aid commercialisation, universities are transforming into ‘entrepreneurial’ institutions.1 University administrators seek to generate new funding streams, while governments see universities as drivers of technology development and economic growth. In such a climate, it should not be surprising that researchers in many disciplines are facing pressure to collaborate …. (shrink)

Common knowledge is ubiquitous in our lives and yet there remains considerable uncertainty about how to model or understand it. Standard analyses of common knowledge end up being challenged by either regress or circularity which then give rise to well-known paradoxes of practical reasoning, such as the Two Generals’ Paradox. This paper argues that the nature and utility of common knowledge can be illuminated by appeal to Wittgenstein’s Hinge Epistemology. It is argued that those things that we (...) standardly think of as being common knowledge in our lives are the same as those that Wittgenstein identified as hinge certainties. This identification of common knowledge with hinge certainties allows us to resolve the regress problem for common knowledge and explain how the Two Generals’ Paradox arises. (shrink)

In this article, we expand the analytical and theoretical foundations of the study of knowledge commons in the context of more classical agrarian commons, such as seed commons. We show that it is possible to overcome a number of criticisms of earlier work by Ostrom on natural commons and its excludability/rivalry matrix in addressing the inclusive social practices of “commoning”, defined as a way of living and acting for the preservation of the commons. Our (...) empirical analysis emphasizes, using the most recent advances in the IAD/ses framework, the distributed and collaborative knowledge governance in a French peasant seed network as a key driver for reintroducing cultivated agrobiodiversity and on-farm seed conservation of ancient and landrace varieties. These inclusive peasant seed groups developed alternative peer-to-peer models of collaborative peasant-led community-based breeding and grassroots innovations in the search for more resilient population varieties. Our results highlight the various models of collective action within the network and discuss the organizational tradeoffs of opting out of peasant seed activities and recreating a shared collective knowledge base on the benefits of restoring cultivated agrobiodiversity. It helps us better understand how modern peasant seed groups function as epistemic communities which contributes to envisioning alternative agricultural systems. (shrink)

This article presents a community-based account of salience as an alternative and a complement to the ‘natural salience’ approach which is endorsed by almost all game theorists who use this concept. While in the naturalistic approach, salience is understood as an objective and natural property of some entities, the community-based account claims that salience is a function of community membership. Building on David Lewis’s theory of common knowledge and on some of its recent refined accounts, I suggest that salience (...) acts as a correlating device in a correlated equilibrium. What is constitutive of salience is common understanding, the fact that agents have common knowledge that they share the same modes of reasoning with respect to a well-identified set of events. I argue that the basis for common understanding is community membership. The relevance of this account stems from the fact that it answers the objection that salience is either unnecessary or unable to account for coordination between rational agents. (shrink)

Most reductionist accounts of intentional joint action include a condition that it must be common knowledge between participants that they have certain intentions and beliefs that cause and coordinate the joint action. However, this condition has typically simply been taken for granted rather than argued for. The condition is not necessary for ensuring that participants are jointly responsible for the action in which each participates, nor for ensuring that each treats the others as partners rather than as social tools. (...) It is thus something of a mystery why the condition is so widely accepted. By rejecting three arguments that could potentially support it, I argue that reductionists should get rid of the condition. I show that two of the arguments fail. While the third argument is intuitively compelling, it builds on key premises that are unavailable to the reductionist. (shrink)

The first translation into Ukrainian and French of the article "Saber comum e ceticismo” (Common knowledge and skepticism) by Osvaldo Porchat Pereira (1933–2017), which became one of the classic sources of modern Brazilian Neopyrrhonism.

David Lewis is widely credited with the first formulation of common knowledge and the first rigorous analysis of convention. However, common knowledge and convention entered mainstream game theory only when they were formulated, later and independently, by other theorists. As a result, some of the most distinctive and valuable features of Lewis' game theory have been overlooked. We re-examine this theory by reconstructing key parts in a more formal way, extending it, and showing how it differs from more (...) recent game theory. In contrast to current theories of common knowledge, Lewis' theory is based on an explicit analysis of the modes of reasoning that are accessible to rational individuals and so can be used to analyse the genesis of common knowledge. Lewis' analysis of convention emphasises the role of inductive reasoning and of salience in the maintenance of conventions over time. Footnotes Earlier versions of this paper were presented at the 13th Amsterdam Colloquium at the University of Amsterdam, at a workshop on social norms at Wissenschaftskolleg zu Berlin, and at seminars at Tilburg University and the University of Bristol. We are grateful for comments from participants at those meetings, from two anonymous referees, and from Michael Bacharach, Nick Bardsley, Cristina Bicchieri, Luc Bovens, Simon Grant, David McCarthy, Shepley Orr, Brian Skyrms, Peter Vanderschraaf, Peter Wakker and Jörgen Weibull. Robert Sugden's work was supported by the Leverhulme Trust. (shrink)

We study the relationship between common knowledge and the sequence of iterated mutual knowledge from a topological point of view. It is shown that common knowledge is not equivalent to the limit of the sequence of iterated mutual knowledge. On that account the new epistemic operator limit knowledge is introduced and analyzed in the context of games. Indeed, an example is constructed where the behavioral implications of limit knowledge of rationality strictly refine those of (...) common knowledge of rationality. More generally, it is then shown that limit knowledge of rationality is capable of characterizing any solution concept for some appropriate epistemic-topological conditions. Finally, some perspectives of a topologically enriched epistemic framework for games are discussed. (shrink)

The meaning of an utterance is often enriched by the pragmatic context in which it is uttered. This is because in ordinary conversations we routinely and uncontroversially compress what we say, safe in the knowledge that those interpreting us will ‘add in’ the content we intend to communicate. Does the same thing hold true in the case of legal utterances like ‘This constitution protects the personal rights of the citizen’ or ‘the parliament shall have the power to lay and (...) collect taxes’? This article addresses this question from the perspective of the constitutional originalist—the person who holds that the meaning of a constitutional text is fixed at some historical moment. In doing so, it advances four theses. First, it argues that every originalist theory is committed to some degree of pragmatic enrichment, the debate is about how much. Second, that in determining which content gets ‘added in’, originalists typically hold to a common knowledge standard for enrichment, protestations... (shrink)

We develop a logical system that captures two different interpretations of what extensive games model, and we apply this to a long-standing debate in game theory between those who defend the claim that common knowledge of rationality leads to backward induction or subgame perfect (Nash) equilibria and those who reject this claim. We show that a defense of the claim à la Aumann (1995) rests on a conception of extensive game playing as a one-shot event in combination with a (...) principle of rationality that is incompatible with it, while a rejection of the claim à la Reny (1988) assumes a temporally extended, many-moment interpretation of extensive games in combination with implausible belief revision policies. In addition, the logical system provides an original inductive and implicit axiomatization of rationality in extensive games based on relations of dominance rather than the usual direct axiomatization of rationality as maximization of expected utility. (shrink)

Typically, common knowledge is taken as grounds for the acceptability of a claim, while appeals to popularity are seen as fallacious attempts to support a claim. This paper poses the question of whether there is any categorical difference between appeals to common knowledge and appeals to popular opinion as argumentative moves. In answering this question, I argue that appeals to common knowledge do not, on their own, provide adequate grounds for a claim’s acceptability.

Using epistemic logic, we provide a non-probabilistic way to formalise payoff uncertainty, that is, statements such as ‘player i has approximate knowledge about the utility functions of player j.’ We show that on the basis of this formalisation common knowledge of payoff uncertainty and rationality (in the sense of excluding weakly dominated strategies, due to Dekel and Fudenberg (1990)) characterises a new solution concept we have called ‘mixed iterated strict weak dominance.’.

This paper investigates the epistemic assumptions that David Lewis makes in his account of social conventions. In particular, I focus on the assumption that the agents have common knowledge of the convention to which they are parties. While evolutionary analyses show that the common knowledge assumption is unnecessary in certain classes of games, Lewis’ original account (and, more recently, Cubitt and Sugden’s reconstruction) stresses the importance of including it in the definition of convention. I discuss arguments pro et (...) contra to argue that, although the assumption might be relevant to a descriptively adequate account of social convention, it is not required for its rational reconstruction. I then point out that Lewis’ account, properly speaking, is of common reason to believe, rather than of common knowledge, and argue that, in order to formalize aptly the distinction between reason to believe and belief, standard formal epistemic models need to be supplemented with so-called awareness structures. Finally, I stress that the notion of knowledge implicit in Lewis’ text involves interesting elements that cannot be captured in the standard propositional formalizations, but need the full expressive force of quantified epistemic logic. (shrink)

Can we know anything for certain? There are those who think we can (traditionally labeled the "dogmatists") and those who think we cannot (traditionally labeled the "skeptics"). The theory of knowledge, or epistemology, is the great debate between the two. This book is an introductory and historically-based survey of the debate. It sides for the most part with the skeptics. It also develops out of skepticism a third view, fallibilism or critical rationalism, which incorporates an uncompromising realism about perception, (...) science, and the nature of truth. (shrink)

The two of us commonly know a proposition just in case (i) we both know it, (ii) we both know that we both know it, (iii) we both know that we both know that we both know it, and so on. In a recent paper titled ‘Uncommon Knowledge’, Harvey Lederman (2018) argues against the possibility of common knowledge. His argument rests on the empirical claim that there are minor individual variations in how we perceive things. This motivates a (...) principle about perception: when two people are perceiving something and it perceptually appears a certain way to one of them, then for all that person knows, it perceptually appears a slightly different way to the other. In this paper, I challenge Lederman’s perceptual principle and thereby his argument. In particular, I argue that there are some circumstances in which things perceptually appear a certain way to me and nonetheless I know that they don’t perceptually appear in a slightly different way to you. Indeed, I argue that not only are there exceptions to the perceptual principle, but they are widespread. (shrink)

An opinionated introduction to philosophical issues connected to common knowledge.

Using epistemic logic, we provide a non-probabilistic way to formalise payoff uncertainty, that is, statements such as ‘player i has approximate knowledge about the utility functions of player j.’ We show that on the basis of this formalisation common knowledge of payoff uncertainty and rationality (in the sense of excluding weakly dominated strategies, due to Dekel and Fudenberg (1990)) characterises a new solution concept we have called ‘mixed iterated strict weak dominance.’.

Although most of us know that human beings cannot and should not be replaced by computers, we have great difficulties saying why this is so. This paradox is largely the result of institutionalizing several fundamental misconceptions as to the nature of both trustworthy objective and moral knowledge. Unless we transcend this paradox, we run the increasing risks of becoming very good at counting without being able to say what is worth counting and why. The degree to which this is (...) occurring is the degree to which the computer revolution is already over — and the degree to which we human beings have lost. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Philosophy and Rhetoric 34.2 (2001) 93-112 [Access article in PDF] Enthymemes, Common Knowledge, and Plausible Inference Douglas Walton The study of enthymemes has always been regarded as important in logic, critical thinking, and rhetoric, but too often it is the formal or mechanistic aspect of it that has been in the forefront. This investigation will show that there is a kind of plausibilistic script-based reasoning, of a kind (...) that has mainly been studied in artificial intelligence, that should have a much more important role to play in the study of enthymemes. But then curiously, as will also be shown, this plausibilistic type of reasoning was familiar in the ancient world, to the Sophists, as well as to leading philosophers such as Plato and Aristotle. By linking this ancient notion of plausibility to the modern notion used in computer science, this investigation reveals an important basis for the enthymeme that has a type of logical structure in its own right, but also has an informal aspect.An enthymeme, in current usage, is an argument that has one or more premises, or possibly a conclusion, not explicitly stated in the text, but that needs to have these propositions explicitly stated to extract the complete argument from the text. Sometimes enthymemes are described as arguments with "missing premises." That vocabulary is awkward, however, because the nonexplicit statement that needs to be added can be a conclusion, at least in a minority of cases. To make the exposition below smoother, the term nonexplicit assumption will be used to cover either the case of a nonexplicit premise or that of a nonexplicit conclusion. The problem with enthymemes is that if the nonexplicit assumptions in an argument are supposed to be propositions used by the arguer (as opposed to just the propositions needed to make the argument structurally correct, according to some standard), reasonable people can have differences of opinion on what the nonexplicit assumptions are supposed to be. The problem is that filling in the missing parts of enthymemes depends on interpreting the natural language [End Page 93] in which the argument was put forward to try to determine what the speaker meant to say.The solution to the problem comes through the recognition that enthymemes rest not only on formal (structural) criteria, but also on informal criteria. One of the most important of these informal criteria is something often called "common knowledge" (Govier 1992; Freeman 1995). But as shown below in a set of selected case studies of enthymemes, "common knowledge" is not really a kind of knowledge at all. It is really plausibility, or eikos, something well known in the ancient world and often misleadingly translated as "probability." Curiously, Aristotle's original doctrine of the enthymeme was based on this notion of plausibility. This historical fact has often been a source of puzzlement and confusion, and sometimes it has even been taken to indicate a defect or contradiction in Aristotle's treatment of the enthymeme. However, the goal of this investigation is not primarily historical. It is to work out one of the most important required steps toward a solution to the problem of enthymemes. But to do this, it is necessary to come back to the ancient notion of plausible inference. 1. The problem with enthymemes Once you have any formal theory of inference, like syllogistic, for example, you will be confronted by cases of arguments in everyday discourse that meet all the requirements for a structurally correct inference except that some part or parts, usually a premise or a conclusion, is missing. By "missing" is meant that the proposition in question has not been explicitly stated in the text of discourse, even though it may be clear enough that the speaker (writer) was relying on it, or including it, as part of the argument. The classic example is the following inference: All men are mortal; therefore, Socrates is mortal. To evaluate such an argument, surely some account of the "hidden" or "missing" assumption needs to be taken. The problem with enthymemes (Burke 1985; Gough and Tindale 1985; Hitchcock 1985) is that, if given carte... (shrink)

Openness of knowledge was in the Dutch Republic no more a natural state of affairs than in other parts of Europe at the time, but it became dominant there at an earlier date than elsewhere. This puzzling phenomenon is the subject of this essay. The article shows that tendencies to secrecy in crafts and trades in the Netherlands were by no means absent and that public authorities were not principled supporters of openness. Openness of knowledge did not prevail (...) because arguments in favour of a free exchange of knowledge won the day against a rhetoric in defense of secrecy or because a rapid change in methods of production and marketing rendered the maintenance of craft secrecy practically impossible. The weakness of secrecy in the early-modern Netherlands, this essay argues, can be explained by the relative tardiness of the growth of the corporate system and the typical features of the institutional structure of the Dutch Republic. Craft secrecy in the Dutch Republic, as far as it existed before the middle of the eighteenth century, was normally based on a contractual relationship between individual actors rather than on any form of enforcement by public agencies. (shrink)

We present a new class of models of players’ reasoning in non-cooperative games, inspired by David Lewis's account of common knowledge. We argue that the models in this class formalize common knowledge of rationality in a way that is distinctive, in virtue of modelling steps of reasoning; and attractive, in virtue of being able to represent coherently common knowledge of any consistent standard of individual decision-theoretic rationality. We contrast our approach with that of Robert Aumann, arguing that (...) the former avoids and diagnoses certain paradoxes to which the latter may give rise when extended in particular ways. (shrink)

This chapter makes the case for a relational version of an experientialist view of joint attention. On an experientialist view of joint attention, shifting from solitary attention to joint attention involves a shift in the nature of your perceptual experience of the object attended to. A relational analysis of such a view explains the latter shift in terms of the idea that, in joint attention, it is a constituent of your experience that the other person is, with you, jointly attending (...) to the object. We need such an analysis of joint attention to explain the possibility of success in tasks such as coordinated attack. (shrink)

Not only is the common‐law standard of proof of mere likelihood in ordinary civil cases justifiable, but its justifiability supports the conclusion that there is no general norm that one must assert that p only if p is known. An argument by Voltaire is formalized to show that the mere likelihood standard is rational. It is also shown that no applicable norm preempts the common‐law rule. An objection that takes the pertinent knowledge‐norm to be honoured in the breach is (...) rejected by appeal to the absence of blameworthiness in alleged breaches of interest. An objection that takes civil verdicts to be manifestations of acceptance, rather than assertoric, is considered and rejected. (shrink)

The author discusses the mode of introduction of religious testimonial knowledge as a response to skepticism. It is argued that Professor Greco's Answer to The Argumentfrom Peer Disagreement (Part Three; Application to the three skeptical arguments) requires accepting the thesis that has the same conceptual grounding as the skeptical statements about the impossibility to share any belief. Taking into account this common grounding, it is desirable to explain the statement “A major motivation for anti-skepticism about testimony is anti-skepticism in (...) general" (Part Two). The theory of religious testimonial knowledge uses the statement, which can be grounded by accepting the Mental Holism. However, the Mental Holism is also a possible grounding for some skeptical theses. Thus, a philosopher who assumes religious testimonial knowledge takes not only an anti-skeptical position, but also can take a “proto-skeptical" position. (shrink)

We show the faithful embedding of common knowledge logic CKL into game logic GL, that is, CKL is embedded into GL and GL is a conservative extension of the fragment obtained by this embedding. Then many results in GL are available in CKL, and vice versa. For example, an epistemic consideration of Nash equilibrium for a game with pure strategies in GL is carried over to CKL. Another important application is to obtain a Gentzen-style sequent calculus formulation of CKL (...) and its cut-elimination. The faithful embedding theorem is proved for the KD4-type propositional CKL and GL, but it holds for some variants of them. (shrink)

In his defense of innateness in New Essays on Human Understanding (1704), Leibniz attributes innateness to concepts and principles which do not originate from the senses rather than to the ideas that we are born with. He argues that the innate concepts and principles can be known in two ways: through reason or natural light (necessary truths), and through instincts (other innate truths and principles). In this paper I will show how theoretical and moral reasoning differ from each other in (...) Leibniz, and compare moral reasoning and instincts as sources of knowledge in his practical philosophy. As the practical instincts are closely related to pleasure and passions, which are by nature cognitive, my emphasis will be on the affective character of instinctive moral action and especially deliberation which leads to moral action. I will argue that inclinations arising from moral instinct, which lead us to pleasure while avoiding sorrow, can direct our moral action and sometimes anticipate reasoning when conclusions are not readily available. Acting by will, which is related to moral reasoning, and acting by instincts can lead us to the same moral knowledge independently, but they can also complement each other. To illustrate the two alternative ways to reach moral knowledge, I will discuss the case of happiness, which is the goal of all human moral action for Leibniz. (shrink)

How can participating in a liturgy allow us to know God? Recent pathbreaking work on the epistemology of liturgy has argued that liturgy allows individuals to gain ritual knowledge of God by coming to know-how to engage God. However, since liturgy (as it is ordinarily practiced) is a group act, I argue that we need to give an account to explain how a group can know God by engaging with liturgy. If group know-how is reducible to instances of individual (...) know-how, then the existing accounts are sufficient for explaining a group’s knowing-how to engage God. However, I argue, there are good reasons to suppose that reductive accounts of group know-how fail. In this paper, I propose a non-reductive account of common ritual knowledge, according to which the group knows-how to engage God in liturgy. (shrink)

The coordinated attack scenario and the electronic mail game are two paradoxes of common knowledge. In simple mathematical models of these scenarios, the agents represented by the models can coordinate only if they have common knowledge that they will. As a result, the models predict that the agents will not coordinate in situations where it would be rational to coordinate. I argue that we should resolve this conflict between the models and facts about what it would be rational (...) to do by rejecting common knowledge assumptions implicit in the models. I focus on the assumption that the agents have common knowledge that they are rational, and provide models to show that denying this assumption suffices for a resolution of the paradoxes. I describe how my resolution of the paradoxes fits into a general story about the relationship between rationality in situations involving a single agent and rationality in situations involving many agents. (shrink)

Suppose a speaker S and an audience A are in a communication coordination problem. That is, for some proposition p, they each prefer that S mean that p and that A believe p in response. How do they coordinate their thought and action to solve the problem? The Gricean answer is that they reason their way to the solution. Pragmatics makes a similar assumption. “Pragmatics involves perception augmented by some species of ‘ampliative’ inference … a sort of reasoning”. There are (...) two objections. The first is that it is not plausible to attribute such reasoning to speakers and audiences. The second objection grants, for the sake of argument, that speakers and audiences reason in the required ways. The objection is that this is not sufficient to solve coordination problems since a speaker and an audience may not know how each has reasoned. The problem is well-known in game theory, which typically solves it by assuming the parties’ preferences are common knowledge. Common knowledge is the recursive belief state in which people are know something, know they know it, know they know they know it, ad infinitum. I propose a similar solution. When people interact as speaker and audience, common knowledge arises from their perceptions of each other as fulfilling the roles of speaker and audience. The account of how common knowledge arises entails Grice’s general characterization of conversational implicatures. More precisely, it entails speakers and audiences involved in communication coordination problems typically commonly know that a relevant instance of the conditions holds. The common knowledge approach requires attributing reasoning to speakers and audiences, but it keeps those attributions to a plausible minimum. Thus the common knowledge approach is a viable alternative to current approaches that attribute extensive reasoning to speakers and audiences.A common knowledge-based approach to pragmatics would answer at least the following question: What informative generalizations are possible about the role of contexts in generating common knowledge relevant to conversational implicatures? The question is important. “Much has been learned about these domains of psychology from a focus on the problem of altruistic cooperation and the mechanisms of reciprocity. We hope that comparable insights are waiting to be discovered by psychologists as they investigate the problem of mutualistic cooperation, and the mechanisms of common knowledge are—as we might say—put out there”. (shrink)

The importance of the notion of common knowledge in sustaining cooperative outcomes in strategic situations is well appreciated. However, the systematic analysis of the extent to which small departures from common knowledge affect equilibrium in games has only recently been attempted.We review the main themes in this literature, in particular, the notion of common p-belief. We outline both the analytical issues raised, and the potential applicability of such ideas to game theory, computer science and the philosophy of language.

Some arguments against the assumption that ordinary people may share common knowledge are sound. The apparent cost of such arguments is the rejection of scientific theories that appeal to common knowledge. My proposal is to accept the arguments without rejecting the theories. On my proposal, common knowledge is shared by ideally rational people, who are not just mathematically simple versions of ordinary people. They are qualitatively different from us, and theorizing about them does not lead to predictions (...) about our behavior. Nevertheless, models of action that assume common knowledge have a role to play in our understanding of collective rationality. (shrink)

One does not simply predict where the other will go, which is wherever the first predicts the second to predict the first to go, and so ad infinitum. Not "What would I do if I were she?" but "What would I do if I were she wondering what she would do if she were wondering what I would do if I were she...?".

According to we-mode accounts of collective intentionality, an experience is a "we-experience"—that is, part of a jointly attentional episode—in virtue of the way or mode in which the content of the experience is given to the subject of experience. These accounts are supposed to explain how a we-experience can have the phenomenal character of being given to the subject "as ours" rather than merely "as my experience" (Zahavi 2015), and do so in a relatively conceptually and cognitively undemanding way. Galotti (...) and Frith (2013) and Schmitz (2017) present we-mode accounts that are supposed to, in particular, avoid the need for the subjects of experience to have common knowledge of each other’s perceptual beliefs. In this paper, drawing in part on Schutz’s (1932/1967; 1953) writings on "the pure We-relationship", I argue that appeal to a we-mode does not render common knowledge unnecessary. To explain when we-experiences are veridical, we-mode accounts must (i) explain how a we-experience can enable rational interpersonal coordination in some high-risk situations and (ii) explain why what is experienced is "out in the open" between the subjects of the we-experience. To do this, proponents of we-mode accounts need an account of common knowledge. In addition, they must explain why certain inferences hold between we-mode and I-mode attitudes. In light of this, we-mode accounts fare no better than content accounts in illuminating how basic forms of collective intentionality are possible. (shrink)

What is the relation between joint attention and common knowledge? On the one hand, the relation seems tight: the easiest and most reliable way of knowing something in common with another is for you and that other to be attentively aware of what you are together experiencing. On the other hand, they couldn’t seem further apart: joint attention is a mere perceptual phenomena that infants are capable of engaging in from nine months of age, whereas common knowledge is (...) a cognitive phenomenon involving (so it seems) complex, overlapping metarepresentational states that require the kind of sophisticated mindreading skills that developmental psychology has shown to be beyond the capabilities of young children. In 'The Shared World: Perceptual Common Knowledge, Demonstrative Communication, and Shared Social Space', Axel Seemann attempts, inter alia, to makensense of this conundrum. (shrink)