The problem of intentional identity, as originally offered by Peter Geach, says that there can be an anaphoric link between an indefinite term and a pronoun across a sentential boundary and across propositional attitude contexts, where the actual existence of an individual for the indefinite term is not presupposed. In this paper, a semantic resolution to this elusive puzzle is suggested, based on a new quantified intensional logic and game-theoretic semantics (GTS) of imperfect information. This constellation leads to an expressive (...) intensional language with a property of informational independence, argued to produce a purely semantic explication to intentional identity statements. One consequence is that various extra-logical and pragmatic factors become of secondary concern; it is possible to solve the puzzle by logico-semantic methods, albeit somewhat radically renewed ones. (shrink)

This paper examines the contemporary philosophical and cognitive relevance of Charles Peirce's diagrammatic logic of existential graphs (EGs), the ‘moving pictures of thought’. The first part brings to the fore some hitherto unknown details about the reception of EGs in the early 1900s that took place amidst the emergence of modern conceptions of symbolic logic. In the second part, philosophical aspects of EGs and their contributions to contemporary logical theory are pointed out, including the relationship between iconic logic and (...) images, the problem of the meaning of logical constants, the cognitive economy of iconic logic, the failure of the Frege–Russell thesis, and the failure of the Language of Thought hypothesis. (shrink)

This book shows, for the first time in its full spectrum, the interconnectedness and topicality of two historically and philosophically significant developments of philosophical theories of the study of mind: that of phenomenology of Edmund Husserl and phaneroscopy of Charles S. Peirce. The chapters in this book put the two thinkers in a novel discourse while engaging in mutual scholarship on the large overlaps between the historically two largely independently developed but converging ideas of mind, cognition, consciousness, being, and experience. (...) It is the second volume in a projected series of three, the first of which is Peirce and Husserl: Mutual Insights on Logic, Mathematics, and Cognition (2019). This book consists of three parts. Part I contains studies on the basic elements and the methodological themes of both “phenomenologies” vis-à-vis each other. Part II of the book is dedicated to metaphysical and existential themes. Finally, this book contains a hitherto unpublished selection of connected texts from Charles Peirce concerning phaneroscopy, the theory of definitions, and other related historical, philosophical, and religious themes from 1910, transcribed and introduced by one of the editors of the volume. This book is of interest to scholars in phenomenology, phaneroscopy, and the history of ideas. (shrink)

This volume aims to provide the elements for a systematic exploration of certain fundamental notions of Peirce and Husserl in respect with foundations of science by means of drawing a parallelism between their works. Tackling a largely understudied comparison between these two contemporary philosophers, the authors highlight the significant similarities in some of their fundamental ideas. This volume consists of eleven chapters under four parts. The first part concerns methodologies and main principles of the two philosophers. An introductory chapter outlines (...) central historical and systematical themes arising out of the recent scholarship on Peirce and Husserl. The second part is on logic, its Chapters dedicated to the topics from Peirce’s Existential Graphs and the philosophy of notation to Husserl’s notions of pure logic and transcendental logic. The third part includes contributions on philosophy of mathematics. Chapters in the final part deal with the theory of cognition, consciousness and intentionality. The closing chapter provides an extended glossary of central terms of Peirce’s theory of phaneroscopy, explaining them from the viewpoint of the theory of cognition. (shrink)

This paper proposes to recover the topic of the philosophy of scientific method from its late nineteenth-century roots. The subject matter of scientific method sprouted from key inferential ingredients identified by Charles Peirce. In this paper, the historical path is traversed from the viewpoint of contemporary Cognitive Structural Realism (CSR). Peirce’s semiotic theory of methods and practices of scientific inquiry prefigured CSR’s reliance on embodied informational structures and experimentation upon forms of relations that model generic scientific domains. Three results (...) are shown to follow from this convocation: (i) a naturalization of Peirce’s interconnected abductive, deductive and inductive stages of the logic of science, here characterized de novo in terms of CSR. (ii) a perspective to scientific modeling that incorporates processes of abstraction and generalization as originated from Peirce’s logic of science, and (iii) diagrammatic reasoning as a pivotal method in analyzing scientific reasoning in experimental practices. (shrink)

The background target of the research going into the present article is to forge an intellectual alliance between, on the one hand, active inference and the free-energy principle (FEP), and on the other, Charles S. Peirce’s theory of semiotics and pragmatism. In the present paper, the focus is on the allegiance between the nomenclatures of active and abductive inferences as the proper place to begin reaching at that wider target. The paper outlines the key conceptual elements involved in a naturalistic (...) rendering of Peirce’s late semiotic and logical notion of abductive reasoning. The target is a cognitive-biological model of abduction which preserves the functional integrity of an organism and fulfils the existential imperative for living beings’ evidence of existence. Such a model is an adaptation of Peirce’s late logical schema of abduction proposed in his largely unpublished works during the early 20th century. The proposed model is argued to be a feasible sketch also of recent breakthroughs in computational (sensu Bayesian) cognitive science. (shrink)

The theory of existential graphs, which Peirce ultimately divided into four quadrants , is a rich method of analysis in the philosophy of logic. Its $$\upbeta $$ β -part boasts a diagrammatic theory of quantification, which by 1902 Peirce had used in the logical analysis of natural-language expressions such as complex donkey-type anaphora, quantificational patterns describing new mathematical concepts, and cognitive information processing. In the $$\upbeta $$ β -quadrant, he came close to inventing independence-friendly logic, the idea of which (...) he found indispensable in fulfilling the tasks –. (shrink)

This paper addresses the theoretical notion of a game as it arisesacross scientific inquiries, exploring its uses as a technical andformal asset in logic and science versus an explanatory mechanism. Whilegames comprise a widely used method in a broad intellectual realm(including, but not limited to, philosophy, logic, mathematics,cognitive science, artificial intelligence, computation, linguistics,physics, economics), each discipline advocates its own methodology and aunified understanding is lacking. In the first part of this paper, anumber of game theories in formal studies are (...) critically surveyed. Inthe second part, the doctrine of games as explanations for logic isassessed, and the relevance of a conceptual analysis of games tocognition discussed. It is suggested that the notion of evolution playsa part in the game-theoretic concept of meaning. (shrink)

I argue that in aiming to integrate the notions of representation and resemblance in the arts, philosophy of sciences and cognitive sciences one needs to focus on those processes of reasoning and creative inquiry that exploit our faculties of imagination and mental imagery, create novel and useful metaphors based on iconic types of meaning, and may result in discovery through the interactive practices of artists and scientists. To address these matters within the confines of Goodmanian conventionalist and symbolic theories (...) of logic, thought and language is unlikely to deliver these points. A comprehensive philosophy of signs, however, might do the job. (shrink)

This article addresses the problem of the nature of mental imagery from a new perspective. It suggests that sign-theoretical approach as elaborated by C. S. Peirce can give a better and more comprehensive explanation of mental imagery. Our empirical findings follow the methodology of cognitive semiotics and they show that (i) properties of mental images are heterogeneous in nature; (ii) properties of mental images are dependent on the characteristics of object-stimulus; (iii) properties of mental images are dependent on individual (...) differences in imaginary capacities. This suggests that, contrary to representational accounts, mental imagery is not based on one dominant representational format. Imagery constitutes a complex system of signs consisting of several sign elements and dynamic relations. A sign-theoretical account may give a better explanation of the nature of mental imagery, as it accommodates heterogenous evidence from this experiment. (shrink)

Peirce’s claims that methodeutic “concerns abduction alone” and that “pragmatism contributes to the security of reasoning but hardly to its uberty” are explained. They match as soon as a third claim is taken into account, namely that “pragmatism is the logic of abduction,” not of deduction or induction. Since methodeutic concerns abduction and not deduction or induction, it follows that pragmatism is a maxim of methodeutic. Then, since pragmatism contributes to the security of reasoning but not to its uberty, it (...) follows that methodeutic contributes to the security of the only reasoning it is concerned with, namely abduction. We then explain two related issues of methodeutic of abduction. First, in addition to the maxim of pragmatism, which suggests how to choose among experimental hypotheses contributing to the security of reasoning, there is the maxim of simplicity, which suggests hypotheses that are preferable for investment and which contributes to uberty of reasoning. Second, a third maxim of abduction is economy, which suggests adopting hypotheses that contribute to the advantageousness of reasoning even when pragmatism and simplicity cease to apply. These three maxims—experientiality for security, simplicity for uberty, and economy for advantageousness—are the bedrocks of Peirce’s methodeutic of abduction. (shrink)

Mercier and Sperber (MS) have ventured to undermine an age-old assumption in logic, namely the presence of premise-conclusion structures, in favor of two novel claims: that reasoning is an evolutionary product of a reason-intuiting module in the mind, and that theories of logic teach next to nothing about the mechanisms of how inferences are drawn in that module. The present paper begs to differ: logic is indispensable in formulating conceptions of cognitive elements of reasoning, and MS is no less (...) exempt from taking notice of premise-conclusion structures than the commonplace theories of reasoning are. Our counterclaim is realized in terms of diagrammatic reasoning dating back to Charles Peirce’s pragmaticism. The upshot is that pragmatist logic restores the premise-conclusion structures in argumentation, supplants reason-intuition module with logical content, and validates good reasoning as an indispensable resource evident to all rational minds that claim ownership of reason and understanding. (shrink)

The following two review papers have a common origin. Pietarinen’s book Signs of Logic and Stjernfelt’s book Diagrammatology were both published in the same Synthese Library Series being published by Springer. The two books also share the common topic of diagrammatic reasoning in Charles Peirce’s work. Beginning in a conference Applying Peirce held in Helsinki in conjunction with the World Congress of Semiotics in June 2007, two authors have commented upon these books under the headline of Synthese Library Book (...) Session on several occasions, including the Aarhus meeting on Signs and Meaning held in February 2008, the Diagrammatology and Diagram Praxis workshop in Lisboa in March 2009, and the Peirce and Early Analytic Philosophy symposium in Helsinki in June 2009. Therefore, these two review papers form a continuing discussion on the contributions Peirce’s diagrammatic epistemology and logic will have to a broad range of issues at the intersections of philosophy, logic, cognitive sciences and beyond. (shrink)

Are knowledge and belief pivotal in science, as contemporary epistemology and philosophy of science nearly universally take them to be? I defend the view that scientists are not primarily concerned with knowing and that the methods of arriving at scientific hypotheses, models and scenarios do not commit us having stable beliefs about them. Instead, what drives scientific discovery is ignorance that scientists can cleverly exploit. Not an absence or negation of knowledge, ignorance concerns fundamental uncertainty, and is brought out by (...) retroductive inferences, which are roughly characterised as reasoning from effects to causes. I argue that recent discoveries in sciences that coped with under-structured problem spaces testify the prevalence of retroductive logic in scientific discovery and its progress. This puts paid to the need of finding epistemic justification or confirmation to retroductive methodologies. A scientist, never frightened of unknown unknowns, strives to advance the forefront of uncertainty, not that of belief or knowledge. Far from rendering science irrational, I conclude that catering well for the right conditions in which to cultivate ignorance is a key to how fertile retroductive inferences arise. (shrink)

Charles S. Peirce’s pragmatist theory of logic teaches us to take the context of utterances as an indispensable logical notion without which there is no meaning. This is not a spat against compositionality per se , since it is possible to posit extra arguments to the meaning function that composes complex meaning. However, that method would be inappropriate for a realistic notion of the meaning of assertions. To accomplish a realistic notion of meaning (as opposed e.g. to algebraic meaning), Sperber (...) and Wilson’s Relevance Theory (RT) may be applied in the spirit of Peirce’s Pragmatic Maxim (PM): the weighing of information depends on (i) the practical consequences of accommodating the chosen piece of information introduced in communication, and (ii) what will ensue in actually using that piece in further cycles of discourse. Peirce’s unpublished papers suggest a relevance-like approach to meaning. Contextual features influenced his logic of Existential Graphs (EG). Arguments are presented pro and con the view in which EGs endorse non-compositionality of meaning. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Reviewed by:Signs of Logic: Peircean Themes on the Philosophy of Language, Games, and CommunicationRobert W. BurchAhti-Veikko Pietarinen Signs of Logic: Peircean Themes on the Philosophy of Language, Games, and Communication Dordrecht, The Netherlands: Springer, 2006. xiv + 496 pp.This compendious volume of fourteen of Pietarinen's essays on Peirce, plus a three-page set of "Final Words" relating to the work of Robert Aumann, is a "must-have" for both (...) the Peirce scholar and any other philosopher who wishes to relate Peirce's thinking on language and logic to other major thinkers and logical themes of the twentieth century (and beyond). The essays extend or complement discussions of Peirce's logic and philosophy of language that have come to be expected from the "Finnish school" of philosophers, which includes Hintikka and Hilpinen, as well as Pietarinen.Nine of the essays (Chapters 3, 4, 5, 7, 8, 10, 12, 13, and 14), comprising about two-thirds of the entire book, are revised and expanded versions of essays that Pietarinen has previously published. The remaining one-third (approximately) of the book is brand new. Chapters 1 and 2 serve as general introductions to the book's major interests. Chapter 6 is on evidence for constructivism in Peirce, as well as several other topics. Chapter 9 compares Peirce's ideas with Wilfred Hodges's "dialogue foundations" and contains a small philosophical dialogue, which has Peirce, Wittgenstein, and Hodges as its characters. Chapter 11 concerns evolutionary semantics and language [End Page 577] games. And the cursory Chapter 15 of "Final Words" predicts that the game-theoretical approach to semantics and Peirce scholarship has an exploding future, like an erupting volcano.From the foregoing one can gather, correctly, that each essay in the book is separately conceived and that the book is not a single continuous line of argumentative development of one or even of a few themes. Still, the essays are similar to one another in two ways, which ways are closely related to each other. First, they all concern the Peircean doctrine that semeiotic and semeiosis constitute the heartland of logic, and that this heartland is vastly richer than the sort of pure mathematical calculi that might mistakenly be taken for logic itself (and were in fact so taken for much of the twentieth century). Second, they all deal with the Peircean insistence that semeiosis is inherently a form of Praxis in which interchanges occur between or among various "agents" or "actors," one of which might be nature itself; so that at the very least logic is dialogic, and so that more generally one may justifiably speak of semeiosis as involving something like a "game." These lines of exploration will surprise no seasoned Peirce scholar, but the special genius of the Finnish "school" of Peirce interpretation from Hintikka forward is to have spotlighted in dramatic fashion the game-theoretical nature of many elements in Peirce's semeiotic.In these essays Pietarinen amply exhibits two attainments of mind that are indispensable for the serious Peirce scholar. One is the object of what we might call "The Eisele Imperative" after the vehement urgings of Carolyn Eisele: this is the possession of some significant degree of sophistication in mathematics. Pietarinen's mathematical skills are plainly sufficient for his discussions of logic and game theory. For example, his Chapter 5 is an excellent technical discussion of Peirce's existential graphs, and his Chapter 7 is an admirable technical discussion of certain aspects of game theory and generalized quantifiers. Another crucial skill needed by the serious Peirce scholar is the object of what we might call "The Pietarinen Corrective" after the practices exemplified in these essays: this is the possession of extremely broad knowledge of recent and contemporary philosophy, especially philosophy of language, logic, metaphysics, epistemology, and philosophy of science.Indeed, the breadth of Pietarinen's acquaintance with twentieth century logic and philosophy of language, both "analytic" and "continental," is breathtaking. This allows him scope for comparisons of Peirce's views with an extraordinarily wide, and not always easily anticipated, range of philosophers and philosophic traditions. Pietarinen's range of reference is so extensive that it would be pointless to attempt to discuss in... (shrink)

Charles Peirce's theory of proper names is intimately connected to a number of central topics in contemporary philosophy of language and logic. Several papers have appeared in the past in which Peirce's theory of names has been attested to be a precursor of the causal-historical theory of reference.2 The causal-historical theory in turn has customarily been pigeonholed as the 'new' theories of reference that have been emerging since the 1950s (Devitt 1981; Donellan 1966; Kripke 1980; Marcus 1950; Putnam 1973). Among (...) those who have seen Peirce as such a precursor of the new theory of reference are DiLeo (1997), Hilpinen (1995), Maddalena (2006), Pape (1987), and Thibaud (1987). Related recent publications on the .. (shrink)

I will show that the semantic structure of a new imperfect-information propositional logic can be described in terms of extensive forms of semantic games. I will discuss some ensuing properties of these games such as imperfect recall, informational consistency, and team playing. Finally, I will suggest a couple of applications that arise in physics, and most notably in quantum theory and quantum logics.

In this article I bring to light a group of scientific and philosophical ideas and intellectual currents from the early era of the significs movement, contemporaneous with the origins of early analytic philosophy. Significs was a strong candidate for the science of language, meaning, and communication during the new century. Its heyday coincided with the forums of the Vienna Circle, yet its intellectual and cultural climate persisted until fading in the turmoil of the mid-century's analytic thought.

Peirce believed that his pragmaticism can be conclusively proven. Beginning in 1903, he drafted several attempts, ending by 1908 with a semeiotic proof. Around 1905, he exposes the proof using the theory of Existential Graphs . This paper modernizes the semantics Peirce proposed for EGs in terms of game-theoretic semantics . Peirce's 1905 proof is then reconstructed in three parts, by relating pragmaticism to the GTS conception of meaning, showing that Peirce's proof is an argument for a relational structure of (...) the meaning of intellectual signs that our interpretative and strategic practices give rise to, and bringing out the key links between EGs and pragmaticism. (shrink)

I argue that many of the pragmatic notions that are commonly attributed to 1-1. P. Grice, or are reported to be inspired by his work on pragmatics, such as assertion, conventional implicature, cooperation, common ground, common knowledge, presuppositions and conversational strategies, have their origins in C. S. Peirce's theory of signs and his pragmatic logic and philosophy. Both Grice and Peirce rooted their theories in normative rationality, anti-psychologism and the relevance of assertions. With respect to the post-Gricean era of pragmatics, (...) theories of relevance may be seen to have been geared, albeit unconsciously, upon Peirce's pragmatic agenda. (shrink)

Peirce aspired for the completeness of his logic cum the theory of signs in his 1903 Lowell Lectures and other late manuscripts. Semeiotic completeness states that everything that is a consequence in logical critic is derivable in speculative grammar. The present paper exposes the reasons why Peirce would fall short of establishing semeiotic completeness and thus why he would not continue seeking a perfect match between the theories of grammar and critic. Some alternative notions are then proposed.

Peirce divided hypoicons into images, diagrams, and metaphors. For diagrams, he developed a logical theory of graphs: many-dimensional linguistic expressions analyzing meaning by virtue of iconicity of logical form. He neglected the logic of images as well as metaphors, however. Metaphors relate to non-standard meanings that combine complex diagrammatic representations. Images are elementary constituents of qualitative space. I will argue that the interpretation of images corresponds to the interpretation of non-logical vocabularies. This raises the question of whether images are also (...) linguistic, in other words whether the simple qualities they partake of are the simple qualities of some propositional content. I will argue that Peirce favored a picture theory of language that takes images to interpret elementary characters of objects that constitute propositions. He did not ascribe images with properties of propositions, as that would have rendered them non-hypoiconic signs. (shrink)

We present a dynamic approach to Peirce’s original construal of abductive logic as a logic of conjecture making, and provide a new decidable, contraction-free and cut-free proof system for the dynamic logic of abductive inferences with neighborhood semantics. Our formulation of the dynamic logic of abduction follows the philosophical and scientific track that led Peirce to his late, post-1903 characterization of abductive conclusions as investigands, namely invitations to investigate propositions conjectured at the level of pre-beliefs.

We propose a reconstruction of the constellation of problems and philosophical positions on the nature and number of the primitives of logic in four authors of the nineteenth century logical scene: Peano, Padoa, Frege and Peirce. We argue that the proposed reconstruction forces us to recognize that it is in at least four different senses that a notation can be said to be simpler than another, and we trace the origins of these four senses in the writings of these authors. (...) We conclude that Frege, and even more so Peirce, developed new notations not to make drawing logical conclusions easier but in order to answer the needs of logical analysis. (shrink)

The logic of worldviews provides a consistent method of comparison between multiple worldviews. The present paper connects the logic of worldviews to important historical and contemporary influences. Beginning with its roots in semiotics, an account of epistemology emerges which is mediated by a belief system. We show that Charles Peirce’s pragmatistic theory of inquiry is the bedrock beneath the logic of worldviews. We formulate it as a generalized version of inquiry with underlying game-theoretic semantics. In this paper, we extend Peirce’s (...) triadic model of signs to cover knowledge mediated by systems of beliefs. Michael Polanyi’s account of personal commitment includes a subsidiary/focal distinction that views theoretical frameworks as tools for interpreting orders of reality through actual practices of research. We also see how a precedent is set by Johan Georg Hamann’s epistemology of belief, recovered by Ludwig Wittgenstein, using reason as an interpretation of God’s speech in nature. We argue that Thomas Kuhn’s theory of inquiry and worldviews (or paradigms) may be fruitfully contrasted with Peirce’s theory, with reasoning by abduction, deduction, and induction occurring within the community of inquirers. The upshot is that although worldviews may be adopted for non-rational reasons, one can meaningfully compare worldviews through a method proposed by Alasdair MacIntyre: the proponent of a theory learns the language of competing theories and uses them as a metatheory to show how one’s own theory may not have the resources to resolve certain problematic situations. Our result is a meta-linguistic falsification in the sense of Peirce’s semiotics and pragmaticism: the competing theory may be used to show that the object theory does not have a strategy at its disposal to interpret the anomalous phenomenon. (shrink)

: This paper discusses the American scientist and philosopher Charles S. Peirce's (1839–1914) classification of the sciences from the contemporary perspective of interdisciplinary studies. Three theses are defended: (1) Studies on interdisciplinarity pertain to the intermediate class of Peirce's classification of all science, the sciences of review (retrospective science), ranking below the sciences of discovery (heuretic sciences) and above practical science (the arts). (2) Scientific research methods adopted by interdisciplinary inquiries are cross-categorial. Making them converge to an increasing extent with (...) the sciences of discovery, especially the methodeutic of normative logic, is one of the future challenges for studies on interdisciplinarity. (3) The overall structure of Peirce's classification, were it to be applied in today's situation, would not, in any major respect, be radically different from what it was designed to reflect a hundred years ago, in spite of the virtually exponential creation and production of new domains and the massive increase in investment in research and scientific publication. Accordingly, charges that the sciences of discovery are becoming ever more fragmented are not new. (shrink)

This paper compares Peirce’s and Hintikka’s logical philosophies and identifies a cross-section of similarities in their thoughts in the areas of action-first epistemology, pragmaticist meaning, philosophy of science, and philosophy of logic and mathematics.

Scientific evidence and scientific values under risk and uncertainty are strictly connected from the point of view of Peirce’s pragmaticism. In addition, economy and statistics play a key role in both choosing and testing hypotheses. Hence we may show also the connection between the methodology of the economy of research and statistical frequentism, both originating from pragmaticism. The connection is drawn by the regulative principles of synechism, tychism and uberty. These principles are values that have both epistemic and non-epistemic dimension. (...) They concern both the decisions to test a hypothesis as well as inductive risk. The validity of this result stems from the values cost–benefit analysis imposes on scientific inquiry. Values associated with the economy of research are important not only in the pre-test phases of generating hypotheses but also when hypotheses are effectively tested. Peirce took these economic considerations to leave room for an interpretation of probability which is not only a frequentist and propensity-theoretic but also a conceptualist one referring to degrees of belief. We show that this leeway nonetheless agrees with the theory of the economy of scientific methods. (shrink)

This special issue of Synthese on Peirce’s Logic and Philosophy of Language collects papers by Rocco Gangle & Gianluca Caterina, Chuangshen He, Risto Hilpinen, Matthew Moore, Charles S. Peirce, Ahti-Veikko Pietarinen and Frederik Stjernfelt.Charles Sanders Peirce was a scientist, philosopher, mathematician and semiotician, as well as one of the undisputed giants in the founding of modern logic. He advanced virtually endless areas in exact sciences. He worked throughout his long career as a scientist, logician, philosopher, mathematician, and meaning (...) analyst. As an advocate of developing and applying new methods and theories to improve logical analysis, his innovations included algebraic methods, quantification theory, semantics and pragmatics of communication, ethics and philosophy of notation, as well as comprehensive systems of diagrammatic logics which he termed existential graphs. Peirce held an exceptionally wide conception of logic, conceived as semeiotic, which he to .. (shrink)

This paper presents an enrichment of the Gabbay–Woods schema of Peirce’s 1903 logical form of abduction with illocutionary acts, drawing from logic for pragmatics and its resources to model justified assertions. It analyses the enriched schema and puts it into the perspective of Peirce’s logic and philosophy.

How are we to understand the talk about properties of structures the existence of which is conditional upon the assumption of the reality of those structures? Mathematics is not about abstract objects, yet unlike fictionalism, modal-structuralism respects the truth of theorems and proofs. But it is nominalistic with respect to possibilia. The problem is that, for fear of reducing possibilia to actualities, the second-order modal logic that claims to axiomatise modal existence has no real semantics. There is no cross-identification of (...) higher-order mathematical entities and thus we cannot know what those entities are. I suggest that a scholastic notion of realism, interspersed with cross-identification of higher-order entities, can deliver the semantics without collapse. This semantics of modalities is related to Peirce's logic and his pragmaticist philosophy of mathematics. (shrink)

Abductive conclusions are drawn in a special, co-hortative mood. Abductive conclusions are representative interpretants that represent abduction as a form of reasoning that can convey a general conception of the truth. The truth is not asserted; abduction merely delivers the idea of a matter of course, rendering that idea comparatively simple and natural, hence assuring us of its justified assertibility. Hence abductive reasoning is at home in addressing ‘How Possible’-questions in science. Abductive reasoning concerns the question of how things might, (...) could or would conceivably be such that they can be plausibly asserted. Peirce took all reasoning to be diagrammatic and representable using the graphical method of logic. Yet no examples have previously been found in his large manuscript corpus of what such non-deductive graphs might look like. This paper proposes a new interpretation of a sole exception, a sketch of two graphs from a rejected page from 1903, which might be the only surviving example of Peirce’s abductive graphs. The proposed interpretation takes them to be representative interpretants of this special inverse type of inference. (shrink)

This paper provides an analysis of the notational difference between Beta Existential Graphs, the graphical notation for quantificational logic invented by Charles S. Peirce at the end of the 19th century, and the ordinary notation of first-order logic. Peirce thought his graphs to be “more diagrammatic” than equivalently expressive languages for quantificational logic. The reason of this, he claimed, is that less room is afforded in Existential Graphs than in equivalently expressive languages for different ways of representing the same fact. (...) The reason of this, in turn, is that Existential Graphs are a non-linear, occurrence-referential notation. As a non-linear notation, each graph corresponds to a class of logically equivalent but syntactically distinct sentences of the ordinary notation of first-order logic that are obtained by permuting those elements that in the graphs lie in the same area. As an occurrence-referential notation, each Beta graph corresponds to a class of logically equivalent but syntactically distinct sentences of the ordinary notation of first-order logic in which the identity of reference of two or more variables is asserted. In brief, Peirce’s graphs are more diagrammatic than the linear, type-referential notation of first-order logic because the function that translates the latter to the graphs does not define isomorphism between the two notations. (shrink)

A century ago, Charles S. Peirce proposed a logical approach to modalities that came close to possible-worlds semantics. This paper investigates his views on modalities through his diagrammatic logic of Existential Graphs. The contribution of the GAMMA part of EGs to the study of modalities is examined. Some ramifications of Peirce's remarks are presented and placed into a contemporary perspective. An appendix is included that provides a transcription with commentary of Peirce's unpublished manuscript on modality from 1901.

The problem of intentional identity, as originally offered by Peter Geach, says that there can be an anaphoric link between an indefinite term and a pronoun across a sentential boundary and across propositional attitude contexts, where the actual existence of an individual for the indefinite term is not presupposed. In this paper, a semantic resolution to this elusive puzzle is suggested, based on a new quantified intensional logic and game-theoretic semantics (GTS) of imperfect information. This constellation leads to an expressive (...) intensional language with a property of informational independence, argued to produce a purely semantic explication to intentional identity statements. One consequence is that various extra-logical and pragmatic factors become of secondary concern; it is possible to solve the puzzle by logico-semantic methods, albeit somewhat radically renewed ones. (shrink)

Charles Peirce’s alpha system \ is reformulated into a deep inference system where the rules are given in terms of deep graphical structures and each rule has its symmetrical rule in the system. The proof analysis of \ is given in terms of two embedding theorems: the system \ and Brünnler’s deep inference system for classical propositional logic can be embedded into each other; and the system \ and Gentzen sequent calculus \ can be embedded into each other.

It is of common use in modern Venn diagrams to mark a compartment with a cross to express its non-emptiness. Modern scholars seem to derive this convention from Charles S. Peirce, with the assumption that it was unknown to John Venn. This paper demonstrates that Venn actually introduced several methods to represent existentials but felt uneasy with them. The resistance to formalize existentials was not limited to diagrammatic systems, as George Boole and his followers also failed to provide a satisfactory (...) symbolic representation for them. This difficulty points out issues that are inherent to the very nature of existentials. This paper assesses the various methods designed for the representation of existential statements with Venn diagrams. First, Venn’s own attempts are discussed and compared with other solutions proposed by his contemporaries and successors, notably Lewis Carroll and Peirce. Since disjunctives hold an important role in an effective representation of existentials, their representation is also discussed. Finally, recent methods for the diagrammatic representation of existing individuals, rather than mere existence, are surveyed. (shrink)

Abstraction and generalization are two processes of reasoning that have a special role in the construction of scientific theories and models. They have been important parts of the scientific method ever since the nineteenth century. A philosophical and historical analysis of scientific practices shows how abstraction and generalization found their way into the theory of the logic of science of the nineteenth-century philosopher Charles S. Peirce. Our case studies include the scientific practices of Francis Galton and John Herschel, who introduced (...) composite photographs and graphical methods, respectively, as technologies of generalization and thereby influenced Peirce’s logic of abstraction. Herschel’s account of generalization is further supported by William Whewell, who was very influential on Peirce. By connecting Herschel’s scientific technology of abstraction to Peirce’s logical technology of abstraction—namely, diagrams—we highlight the role of judgments in scientific observation by hypostatic abstractions. We also relate Herschel’s discovery-driven logic of science and Peirce’s open-ended diagrammatic logic to the use of models in science. Ultimately, Peirce’s theory of abstraction is a case of showing how logic applies to reality. (shrink)

We propose a reconstruction of the constellation of problems and philosophical positions on the nature and number of the primitives of logic in four authors of the nineteenth century logical scene: Peano, Padoa, Frege and Peirce. We argue that the proposed reconstruction forces us to recognize that it is in at least four different senses that a notation can be said to be simpler than another, and we trace the origins of these four senses in the writings of these authors. (...) We conclude that Frege, and even more so Peirce, developed new notations not to make drawing logical conclusions easier but in order to answer the needs of logical analysis. (shrink)

Modern explainable AI methods remain far from providing human-like answers to ‘why’ questions, let alone those that satisfactorily agree with human-level understanding. Instead, the results that such methods provide boil down to sets of causal attributions. Currently, the choice of accepted attributions rests largely, if not solely, on the explainee’s understanding of the quality of explanations. The paper argues that such decisions may be transferred from a human to an XAI agent, provided that its machine-learning algorithms perform genuinely abductive inferences. (...) The paper outlines the key predicament in the current inductive paradigm of ML and the associated XAI techniques, and sketches the desiderata for a truly participatory, second-generation XAI, which is endowed with abduction. (shrink)

Peirce considered the principal business of logic to be the analysis of reasoning. He argued that the diagrammatic system of Existential Graphs, which he had invented in 1896, carries the logical analysis of reasoning to the furthest point possible. The present paper investigates the analytic virtues of the Alpha part of the system, which corresponds to the sentential calculus. We examine Peirce’s proposal that the relation of illation is the primitive relation of logic and defend the view that this idea (...) constitutes the fundamental motive of philosophy of notation both in algebraic and graphical logic. We explain how in his algebras and graphs Peirce arrived at a unifying notation for logical constants that represent both truth-function and scope. Finally, we show that Shin’s argument for multiple readings of Alpha graphs is circular. (shrink)

The logic of assertive graphs (AGs) is a modification of Peirce’s logic of existential graphs (EGs), which is intuitionistic and which takes assertions as its explicit object of study. In this paper we extend AGs into a classical graphical logic of assertions (ClAG) whose internal logic is classical. The characteristic feature is that both AGs and ClAG retain deep-inference rules of transformation. Unlike classical EGs, both AGs and ClAG can do so without explicitly introducing polarities of areas in their language. (...) We then compare advantages of these two graphical approaches to the logic of assertions with a reference to a number of topics in philosophy of logic and to their deep-inferential nature of proofs. (shrink)

This article investigates Charles Peirce’s development of logical calculi for classical propositional logic in 1880–1896. Peirce’s 1880 work on the algebra of logic resulted in a successful calculus for Boolean algebra. This calculus, denoted byPC, is here presented as a sequent calculus and not as a natural deduction system. It is shown that Peirce’s aim was to presentPCas a sequent calculus. The law of distributivity, which Peirce states in 1880, is proved using Peirce’s Rule, which is a residuation, inPC. The (...) transitional systems of the algebra of the copula that Peirce develops since 1880 paved the way to the 1896 graphical system of the alpha graphs. It is shown how the rules of the alpha system reinterpret Boolean algebras, answering Peirce’s statement that logical graphs supply a new system of fundamental assumptions to logical algebra. A proof-theoretic analysis is given for the connection betweenPCand the alpha system. (shrink)

Some have suggested that images can be arguments. Images can certainly bolster the acceptability of individual premises. We worry, though, that the static nature of images prevents them from ever playing a genuinely argumentative role. To show this, we call attention to a dilemma. The conclusion of a visual argument will either be explicit or implicit. If a visual argument includes its conclusion, then that conclusion must be demarcated from the premise or otherwise the argument will beg the question. If (...) a visual argument does not include its conclusion, then the premises on display must license that specific conclusion and not its opposite, in accordance with some demonstrable rationale. We show how major examples from the literature fail to escape this dilemma. Drawing inspiration from the graphical logic of C. S. Peirce, we suggest instead that images can be manipulated in a way that overcomes the dilemma. Diagrammatic reasoning can take one stepwise from an initial visual layout to a conclusion—thereby providing a principled rationale that bars opposite conclusions—and the visual inscription of this correct conclusion can come afterward in time—thereby distinguishing the conclusion from the premises. Even though this practical application of Peirce’s logical ideas to informal contexts requires that one make adjustments, we believe it points to a dynamic conception of visual argumentation that will prove more fertile in the long run. (shrink)