We will give here a purely algebraic proof of the cut elimination theorem for various sequent systems. Our basic idea is to introduce mathematical structures, called Gentzen structures, for a given sequent system without cut, and then to show the completeness of the sequent system without cut with respect to the class of algebras for the sequent system with cut, by using the quasi-completion of these Gentzen structures. It is shown that the quasi-completion is a generalization of the MacNeille completion. (...) Moreover, the finite model property is obtained for many cases, by modifying our completeness proof. This is an algebraic presentation of the proof of the finite model property discussed by Lafont [12] and Okada-Terui [17]. (shrink)

Moving from a behavioral definition of intelligence, which describes it as the ability to adapt to the surrounding environment and deal effectively with new situations (Anastasi, 1986), this paper explains to what extent the performance obtained by ChatGPT in the linguistic domain can be considered as intelligent behavior and to what extent they cannot. It also explains in what sense the hypothesis of decoupling between cognitive and problem-solving abilities, proposed by Floridi (2017) and Floridi and Chiriatti (2020) should be interpreted. (...) The problem of symbolic grounding (Harnad, 1990) is then addressed to show the problematic relationship between ChatGPT and the natural environment, and thus the impossibility for it to understand the symbols it manipulates. To explain the reasons why ChatGPT does not succeed in this task, an investigation is carried out and a possible solution to the problem in the artificial domain is proposed by making a comparison with the natural ability of living beings to ground their own meanings from some basic cognitive-sensory aspects, which, it is explained, are directly related to the emergence of self-awareness in humans. Thus, the question is raised whether a possible and concrete solution to the Symbol Grounding Problem would involve in the artificial domain the development of cognitive abilities fully comparable to those of humans. Finally, I explain the difficulties that would have to be overcome before such a level could be reached, since human cognitive capacities are intimately linked to intersubjectivity and intercorporeality. (shrink)

In this commentary, as philosophers of evolutionary biology, we will consider the evolutionary framework used in the Target Article by: (i) emphasising the fruitfulness of the interdisciplinary approach employed; (ii) highlighting some potentially controversial aspects of the proposal; and finally (iii) outlining some ideas for further integration within the UAL framework. The critical analysis will focus on the relationship between learning and consciousness, on the assumed need for a function for consciousness, and on the type of phylogenetic demarcation introduced by (...) UAL. (shrink)

This paper examines the role and power of the state in modernity and its transformation throughout it and into the present. First, it recognizes the centrality of the role of information control for the modern state constitution, which allows sovereign power to extend to the national level. Secondly, it discusses the shift of state power from a purely informational power to an informational and bargaining power, as well as the gradual transformation of sovereignty into governmentality. Finally, it analyzes the transformations (...) that have led to a critical loss of both powers by the state and have enabled their acquisition by tech corporations. It examines the implications of this shift in power and the consequent disempowerment of the state, defining the mode of operation of the power embodied by tech corporations as a regime of performativity, rephrasing the Foucauldian regime of truth, which presided over the ways in which governmental power was performed. Such a regime bases its power not on the ability to order discourse and knowledge, but on the ability to automate it, and to predict and manipulate human behaviors. In this way, it has disintermediated not only the state in its role as the primary informational agent, but also, to some extent, the ability of individuals to assert rights through their actions. (shrink)

When information grows abundant, attention becomes a scarce resource. As a result, agents must plan wisely how to allocate their attention in order to achieve epistemic efficiency. Here, we present a framework for multi-agent epistemic planning with attention, based on Dynamic Epistemic Logic. We identify the framework as a fragment of standard DEL, and consider its plan existence problem. While it is undecidable in the general case, we show that when attention is required for learning, all instances of the problem (...) are decidable. (shrink)

According to the doctrine of the guise of the good, all that is desired is seen by the subject as good to some extent. As a claim about action, the idea is that intentional action, or acting for a reason, is action that is seen as good by the agent. I explore the thesis' main attractions: it provides an account of intentional behavior as something that makes sense to the agent, it paves the way for various views in meta-ethics and (...) normative ethics, and it offers a unified account of practical and theoretical reason. In response to common objections, I examine points of current debate: what is it for something to appear as good? Is value or normative reasons the basic concept at work? How to explain akrasia, perversity in action, and expressive action? I conclude with an overview of alternatives to the guise of the good. (shrink)

A counterpossible conditional is a counterfactual with an impossible antecedent. Common sense delivers the view that some such conditionals are true, and some are false. In recent publications, Timothy Williamson has defended the view that all are true. In this paper we defend the common sense view against Williamson’s objections.

The Humean view that conceivability entails possibility can be criticized via input from cognitive psychology. A mainstream view here has it that there are two candidate codings for mental representations (one of them being, according to some, reducible to the other): the linguistic and the pictorial, the difference between the two consisting in the degree of arbitrariness of the representation relation. If the conceivability of P at issue for Humeans involves the having of a linguistic mental representation, then it is (...) easy to show that we can conceive the impossible, for impossibilities can be represented by meaningful bits of language. If the conceivability of P amounts to the pictorial imaginability of a situation verifying P, then the question is whether the imagination at issue works purely qualitatively, that is, only by phenomenological resemblance with the imagined scenario. If so, the range of situations imaginable in this way is too limited to have a significant role in modal epistemology. If not, imagination will involve some arbitrary labeling component, which turns out to be sufficient for imagining the impossible. And if the relevant imagination is neither linguistic nor pictorial, Humeans will appear to resort to some representational magic, until they come up with a theory of a ‘third code’ for mental representations. (shrink)

Neuroimaging and psychophysiological techniques have proved to be useful in comprehending the extent to which the visual modality is pervasive in mental imagery, and in comprehending the specificity of images generated through other sensory modalities. Although further research is needed to understand the nature of mental images, data attained by means of these techniques suggest that mental imagery requires at least two distinct processing components.

In dynamical systems models feedforward is needed to guide planning and to process unknown and unpredictable events. Feedforward could help Theory of Event Coding (TEC) integrate control processes and could model human performance in action planning in a more flexible and powerful way.

We present a theory of truth in fiction that improves on Lewis's [1978] ‘Analysis 2’ in two ways. First, we expand Lewis's possible worlds apparatus by adding non-normal or impossible worlds. Second, we model truth in fiction as belief revision via ideas from dynamic epistemic logic. We explain the major objections raised against Lewis's original view and show that our theory overcomes them.

I propose a comprehensive account of negation as a modal operator, vindicating a moderate logical pluralism. Negation is taken as a quantifier on worlds, restricted by an accessibility relation encoding the basic concept of compatibility. This latter captures the core meaning of the operator. While some candidate negations are then ruled out as violating plausible constraints on compatibility, different specifications of the notion of world support different logical conducts for negations. The approach unifies in a philosophically motivated picture the following (...) results: nothing can be called a negation properly if it does not satisfy Contraposition and Double Negation Introduction; the pair consisting of two split or Galois negations encodes a distinction without a difference; some paraconsistent negations also fail to count as real negations, but others may; intuitionistic negation qualifies as real negation, and classical Boolean negation does as well, to the extent that constructivist and paraconsistent doubts on it do not turn on the basic concept of compatibility but rather on the interpretation of worlds. (shrink)

_Framing effects_ concern the having of different attitudes towards logically or necessarily equivalent contents. Framing is of crucial importance for cognitive science, behavioral economics, decision theory, and the social sciences at large. We model a typical kind of framing, grounded in (i) the structural distinction between beliefs activated in working memory and beliefs left inactive in long term memory, and (ii) the topic- or subject matter-sensitivity of belief: a feature of propositional attitudes which is attracting growing research attention. We introduce (...) a class of models featuring (i) and (ii) to represent, and reason about, agents whose belief states can be subject to framing effects. We axiomatize a logic which we prove to be sound and complete with respect to the class. (shrink)

I want to model a finite, fallible cognitive agent who imagines that p in the sense of mentally representing a scenario—a configuration of objects and properties—correctly described by p. I propose to capture imagination, so understood, via variably strict world quantifiers, in a modal framework including both possible and so-called impossible worlds. The latter secure lack of classical logical closure for the relevant mental states, while the variability of strictness captures how the agent imports information from actuality in the imagined (...) non-actual scenarios. Imagination turns out to be highly hyperintensional, but not logically anarchic. Section 1 sets the stage and impossible worlds are quickly introduced in Sect. 2. Section 3 proposes to model imagination via variably strict world quantifiers. Section 4 introduces the formal semantics. Section 5 argues that imagination has a minimal mereological structure validating some logical inferences. Section 6 deals with how imagination under-determines the represented contents. Section 7 proposes additional constraints on the semantics, validating further inferences. Section 8 describes some welcome invalidities. Section 9 examines the effects of importing false beliefs into the imagined scenarios. Finally, Sect. 10 hints at possible developments of the theory in the direction of two-dimensional semantics. (shrink)

The fitting attitude analysis of value states that for objects to have value is for them to be the fitting targets of attitudes. Good objects are the fitting targets of positive attitudes, while bad objects are the fitting targets of negative attitudes. The following paper presents an argument to the effect that value and the fittingness of attitudes differ in terms of their explanations. Whereas the fittingness of attitudes is explained, inter alia, by both the properties of attitudes and those (...) of their fitting targets, the explanation of value tends to have a different content. In particular, objects have value in virtue of the features that make them valuable, and these need not involve any attitudinal properties. If this is right, then there are reasons to doubt the claim that for objects to have value is just for them to be the fitting targets of attitudes. Insofar as value is a property, it appears to be distinct from the property of objects being the fitting targets of attitudes. (shrink)

We present and defend the Australian Plan semantics for negation. This is a comprehensive account, suitable for a variety of different logics. It is based on two ideas. The first is that negation is an exclusion-expressing device: we utter negations to express incompatibilities. The second is that, because incompatibility is modal, negation is a modal operator as well. It can, then, be modelled as a quantifier over points in frames, restricted by accessibility relations representing compatibilities and incompatibilities between such points. (...) We defuse a number of objections to this Plan, raised by supporters of the American Plan for negation, in which negation is handled via a many-valued semantics. We show that the Australian Plan has substantial advantages over the American Plan. (shrink)

In this paper I argue that Bykvist’s recent challenges to the fitting-attitude account of value (FA) can be successfully met. The challenge from solitary goods claims that FA cannot account for the value of states of affairs which necessarily rule out the presence of favouring subjects. I point out the modal reasons why FA can account for solitary goods by appealing to contemplative attitudes. Bykvist’s second challenge, the ‘distance problem’, questions the ability of FA to match facts about the intensity (...) of fitting attitudes and facts about value, particularly in the case of solitary goods. I argue that this challenge can be met by including the notion of a veil of ignorance in the formulation of FA, and understanding its role as bracketing the relevance of certain facts when determining the fittingness of attitudes to states of affairs. (shrink)

This article is a critical presentation of Habermas' "Consensual Theory of Truth" as a theory without experience, with a careful analysis of the practical expectations linked by Habermas to this theory.

Realism and utopia usually represent antithetic political perspectives. In this essay I argue that these might find some common points by overtaking the secular interpretation they usually place on themselves.

Research indicates that religious values and ethical behavior are closely associated, yet, at a firm level, the processes by which this association occurs are poorly understood. Family firms are known to exhibit values-based behavior, which in turn can lead to specific firm-level outcomes. It is also known that one’s family is an important incubator, enabler, and perpetuator of religious values across successive generations. Our study examines the experiences of a single, multigenerational business family that successfully enacted their religious values in (...) their business. Drawing upon intergenerational solidarity and values-based leadership theory, and by way of an interpretive, qualitative analysis, we find that the family’s religious values enhanced their cohesion and were manifested in their leadership style, which, in turn, led to outcomes for the business. Our findings highlight the processes that underlie the relationship between religious values and organizational outcomes in family firms and offer insights into the role of solidarity in values-based leadership. (shrink)

There is some consensus on the claim that imagination as suppositional thinking can have epistemic value insofar as it’s constrained by a principle of minimal alteration of how we know or believe reality to be – compatibly with the need to accommodate the supposition initiating the imaginative exercise. But in the philosophy of imagination there is no formally precise account of how exactly such minimal alteration is to work. I propose one. I focus on counterfactual imagination, arguing that this can (...) be modeled as simulated belief revision governed by Laplacian imaging. So understood, it can be rationally justified by accuracy considerations: it minimizes expected belief inaccuracy, as measured by the Brier score. (shrink)

A complex brain network, centered on the hippocampus, supports episodic memories throughout their lifetimes. Classically, upon memory encoding during active behavior, hippocampal activity is dominated by theta oscillations (6-10Hz). During inactivity, hippocampal neurons burst synchronously, constituting sharp waves, which can propagate to other structures, theoretically supporting memory consolidation. This 'two-stage' model has been updated by new data from high-density electrophysiological recordings in animals that shed light on how information is encoded and exchanged between hippocampus, neocortex and subcortical structures such as (...) the striatum. Cell assemblies (tightly related groups of cells) discharge together and synchronize across brain structures orchestrated by theta, sharp waves and slow oscillations, to encode information. This evolving dynamical schema is key to extending our understanding of memory processes. (shrink)

We outline a neo-Meinongian framework labeled as Modal Meinongian Metaphysics (MMM) to account for the ontology and semantics of fictional discourse. Several competing accounts of fictional objects are originated by the fact that our talking of them mirrors incoherent intuitions: mainstream theories of fiction privilege some such intuitions, but are forced to account for others via complicated paraphrases of the relevant sentences. An ideal theory should resort to as few paraphrases as possible. In Sect. 1, we make this explicit via (...) two methodological principles, called the Minimal Revision and the Acceptability Constraint. In Sect. 2, we introduce the standard distinction between internal and external fictional discourse. In Sects. 3–5, we discuss the approaches of (traditional) Meinongianism, Fictionalism, and Realism—and their main troubles. In Sect. 6 we propose our MMM approach. This is based upon (1) a modal semantics including impossible worlds (Subsect. 6.1); (2) a qualified Comprehension Principle for objects (Subsect. 6.2); (3) a notion of existence-entailment for properties (Subsect. 6.3). In Sect. 7 we present a formal semantics for MMM based upon a representation operator. And in Sect. 8 we have a look at how MMM solves the problems of the three aforementioned theories. (shrink)

I present an approach to our conceiving absolute impossibilities—things which obtain at no possible world—in terms of ceteris paribus intentional operators: variably restricted quantifiers on possible and impossible worlds based on world similarity. The explicit content of a representation plays a role similar in some respects to the one of a ceteris paribus conditional antecedent. I discuss how such operators invalidate logical closure for conceivability, and how similarity works when impossible worlds are around. Unlike what happens with ceteris paribus counterfactual (...) conditionals, the closest worlds are relevantly closest belief-worlds: closest to how things are believed to be, rather than to how they are. Also, closeness takes into account apriority and the opacity of intentional contexts. (shrink)

Pragmatic vindicatory genealogies provide both a cause and a rationale and can thus affect the space of reasons. But how far is the space of reasons affected by this kind of genealogical argument? What normative and evaluative implications do these arguments have? In this paper, I unpack this issue into three different sub-questions and explain what kinds of reasons they provide, for whom are these reasons, and for what. In relation to this final sub-question I argue, most importantly, that these (...) arguments are ambiguous about what they give us reasons for, meaning that they can be interpreted both as justifications for recognizing the normative standing of certain norms, values, and practices - and thus for living by them - and as excuses for those that do so. I illustrate this point by reference to the genealogical vindication of honour cultures, showing how the vindicatory argument can illuminate such case as one of excusing moral ignorance. Drawing on legal theory and moral philosophy, I show that different evaluative and normative implications hang on the result of the interpretation as either justification or excuse, and show that this ambiguity is a virtue rather than a limitation. (shrink)

Objective correlates—behavioral, functional, and neural—provide essential tools for the scientific study of consciousness. But reliance on these correlates should not lead to the ‘fallacy of misplaced objectivity’: the assumption that only objective properties should and can be accounted for objectively through science. Instead, what needs to be explained scientifically is what experience is intrinsically— its subjective properties—not just what we can do with it extrinsically. And it must be explained; otherwise the way experience feels would turn out to be magical (...) rather than physical. We argue that it is possible to account for subjective properties objectively once we move beyond cognitive functions and realize what experience is and how it is structured. Drawing on integrated information theory, we show how an objective science of the subjective can account, in strictly physical terms, for both the essential properties of every experience and the specific properties that make particular experiences feel the way they do. (shrink)

Understanding Institutions proposes a new unified theory of social institutions that combines the best insights of philosophers and social scientists who have written on this topic. Francesco Guala presents a theory that combines the features of three influential views of institutions: as equilibria of strategic games, as regulative rules, and as constitutive rules. -/- Guala explains key institutions like money, private property, and marriage, and develops a much-needed unification of equilibrium- and rules-based approaches. Although he uses game theory concepts, (...) the theory is presented in a simple, clear style that is accessible to a wide audience of scholars working in different fields. Outlining and discussing various implications of the unified theory, Guala addresses venerable issues such as reflexivity, realism, Verstehen, and fallibilism in the social sciences. He also critically analyses the theory of “looping effects” and “interactive kinds” defended by Ian Hacking, and asks whether it is possible to draw a demarcation between social and natural science using the criteria of causal and ontological dependence. Focusing on current debates about the definition of marriage, Guala shows how these abstract philosophical issues have important practical and political consequences. -/- Moving beyond specific cases to general models and principles, Understanding Institutions offers new perspectives on what institutions are, how they work, and what they can do for us. (shrink)

The paper presents a positive argument for a version of metaphysically light ethical non-naturalism from the nature of mental states such as desires. It uses as its premise the time-honoured, and recently rediscovered, doctrine of the guise of the good, whereby it is essential to desire that the object of desire be conceived as good or as normatively favoured under some description. The argument is that if the guise of the good is a correct theory of desire, then a certain (...) version of non-naturalism is better placed than other meta-ethical views to make sense of it. First I define ethical non-naturalism and the guise of the good, providing also an initial defence of the latter. Then I briefly survey some historical precedents and proceed to the argument. For each major meta-ethical view I consider I offer reasons why combining them with the guise of the good leads to consequences that are or should be unwelcome by the guise of the good. At the end of this elimination process a form of relatively metaphysically light non-naturalism will emerge as the view that best fits with the guise of the good. (shrink)

Philosophical dialetheism, whose main exponent is Graham Priest, claims that some contradictions hold, are true, and it is rational to accept and assert them. Such a position is naturally portrayed as a challenge to the Law of Non-Contradiction (LNC). But all the classic formulations of the LNC are, in a sense, not questioned by a typical dialetheist, since she is (cheerfully) required to accept them by her own theory. The goal of this paper is to develop a formulation of the (...) Law which appears to be unquestionable, in the sense that the Priestian dialetheist is committed to accept it without also accepting something inconsistent with it, on pain of trivialism—that is to say, on pain of lapsing into the position according to which everything is the case. This will be achieved via (a) a discussion of Priest's dialetheic treatment of the notions of rejection and denial; and (b) the characterization of a negation via the primitive intuition of content exclusion. Such a result will not constitute a cheap victory for the friends of consistency. We may just learn that different things have been historically conflated under the label of 'Law of Non-Contradiction'; that dialetheists rightly attack some formulations of the Law, and orthodox logicians and philosophers have been mistaken in assimilating them to the indisputable one. (shrink)

Accounts of propositions as sets of possible worlds have been criticized for conflating distinct impossible propositions. In response to this problem, some have proposed to introduce impossible worlds to represent distinct impossibilities, endorsing the thesis that impossible worlds must be of the same kind; this has been called the parity thesis. I show that this thesis faces problems, and propose a hybrid account which rejects it: possible worlds are taken as concrete Lewisian worlds, and impossibilities are represented as set-theoretic constructions (...) out of them. This hybrid account (1) distinguishes many intuitively distinct impossible propositions; (2) identifies impossible propositions with extensional constructions; (3) avoids resorting to primitive modality, at least so far as Lewisian modal realism does. (shrink)

I would like to attack a certain view: The view that the concept of identity can fail to apply to some things although, for some positive integer n, we have n of them. The idea of entities without self-identity is seriously entertained in the philosophy of quantum mechanics. It is so pervasive that it has been labelled the Received View. I introduce the Received View in Section 1. In Section 2 I explain what I mean by entity, and I argue (...) that supporters of the Received View should agree with my characterization of the corresponding notion of entity. I also explain what I mean by identity, and I show that supporters of the Received View agree with my characterization of that notion. In Section 3 I argue that the concept of identity, so characterized, is one with the concept of oneness. Thus, it cannot but apply to what belongs to a collection with n elements, n being a positive integer. In Section 4 I add some considerations on the primitiveness of identity or unity and the status of the Identity of Indiscernibles. In Section 5 I address the problem of how reference to indiscernible objects with identity can be achieved. (shrink)

We reply to various arguments by Otavio Bueno and Edward Zalta (‘Object Theory and Modal Meinongianism’) against Modal Meinongianism, including that it presupposes, but cannot maintain, a unique denotation for names of fictional characters, and that it is not generalizable to higher-order objects. We individuate the crucial difference between Modal Meinongianism and Object Theory in the former’s resorting to an apparatus of worlds, possible and impossible, for the representational purposes for which the latter resorts to a distinction between two kinds (...) of predication, exemplification and encoding. We show that encoding has fewer forerunners in the history of philosophy than Bueno and Zalta want, and that there’s a reason why the notion has been found baffling by some. (shrink)

A hyperintensional epistemic logic would take the contents which can be known or believed as more fine-grained than sets of possible worlds. I consider one objection to the idea: Williamson’s Objection from Overfitting. I propose a hyperintensional account of propositions as sets of worlds enriched with topics: what those propositions, and so the attitudes having them as contents, are about. I show that the account captures the conditions under which sentences express the same content; that it can be pervasively applied (...) in formal and mainstream epistemology; and that it is left unscathed by the objection. (shrink)

The history of life on Earth has been shaken in the last half billion years by five mass extinctions that have killed at least three-quarters of biodiversity in a geologically short time. These five extinctions were due to major ecological upheavals, with endogenous or exogenous drivers (volcanic eruptions, impact of asteroids, etc.). Today, many data show that the current extinction rate is comparable to or even worse than that of the Big Five mass extinctions of the past. The difference is (...) that this time the asteroid is one species: Homo sapiens. There are good reasons to include the Sixth Mass Extinction in the definition of the Anthropocene. This drastic reduction in biodiversity will leave an irreversible geological and paleontological mark. It interacts with climate change, with a multiplicative effect. It contributes to the environmental crisis that reduces ecosystem services and threatens human health (i.e., likelihood of spillovers). (shrink)

This paper takes up some threads of Deleuze’s and Ruyer’s engagement with biology. I begin by laying out the main features of Deleuze’s scheme of morphogenesis, through the lens of his references to embryology. I take Deleuze’s interest in embryology to be guided by the effort to define bodies solely by form-generating factors which are immanent to them. His concept of virtuality, which indicates the creative component of reality, the open field of connections defining a body’s capacities for transformation and (...) interaction, plays a key role in this regard. I then consider two implications: (1) The insistence on morphogenesis displaces the question of life from given biological entities, which preserve themselves and act through regulated cycles, to the myriad of activities that compose and modify them; (2) It also rearticulates the distinction between the living and the nonliving, in that it separates the question of life from that of its emergence from a given material arrangement. In the second part I examine these points with greater reference to Ruyer. After introducing Ruyer’s concepts of functioning and formation, I focus on his account of the continuity between biological and physicochemical forms, following some of his work on the microbiology and ethology of the time. The real difference is not between the living and the nonliving, but between two modes of bonding and composition variously operating on all scales: morphogenetic and statistical. I conclude by assessing the significance of this claim with respect to the traditional distinction between vitalism and mechanism. (shrink)

Manufacturing and industry practices are undergoing an unprecedented revolution as a consequence of the convergence of emerging technologies such as artificial intelligence, robotics, cloud computing, virtual and augmented reality, among others. This fourth industrial revolution is similarly changing the practices and capabilities of operators in their industrial environments. This paper introduces and explores the notion of the Operator 4.0 as well as how this novel way of conceptualizing the human operator necessarily implicates human values in the technologies that constitute it. (...) The design approach known as value sensitive design (VSD) is used to explore how these Operator 4.0 technologies can be designed for human values. Expert elicitation surveys were used to determine the values of industry stakeholders and examples of how the VSD methodology can be adopted by engineers in order to design for these values is illustrated. The results provide preliminary adoption strategies that industrial teams can take to Operator 4.0 technology for human values. (shrink)

Barlow's concept of the exploitation of environmental statistical regularities may be more plausibly related to brain mechanisms than Shepard's notion of internalisation. In our view, Barlow endorses a bottom-up approach to neural coding and processing, whereas we suggest that feedback interactions in the visual system, as well as chaotic correlation dynamics in the brain, are crucial in exploiting and assimilating environmental regularities. We also discuss the “conceptual tension” between Shepard's ideas of law internalisation and evolutionary adaptation. [Barlow; Shepard].

Sentences \(\varphi\) and \(\psi\) are _cognitive synonyms_ for one when they play the same role in one’s cognitive life. The notion is pervasive (Sect. 1 ), but elusive: it is bound to be hyperintensional (Sect. 2 ), but excessive fine-graining would trivialize it and there are reasons for some coarse-graining (Sect. 2.1 ). Conceptual limitations stand in the way of a natural algebra (Sect. 2.2 ), and it should be sensitive to subject matters (Sect. 2.3 ). A cognitively adequate individuation (...) of content may be intransitive (Sect. 3 ) due to ‘dead parrot’ series: sequences of sentences \(\varphi _1, \ldots, \varphi _n\) where adjacent \(\varphi _i\) and \(\varphi _{i+1}\) are cognitive synonyms while \(\varphi _1\) and \(\varphi _n\) are not (Sect. 3.1 ). Finding an intransitive account is hard: Fregean equipollence won’t do (Sect. 3.2 ) and a result by Leitgeb shows that it wouldn’t satisfy a minimal compositionality principle (Sect. 3.3 )._Sed contra_, there are reasons for transitivity, too (Sect. 3.4 ). In Sect. 4, we come up with a formal semantics capturing this jumble of desiderata, thereby showing that the notion is coherent. In Sect. 5, we re-assess the desiderata in its light. (shrink)