1. Frege is widely considered to be one of the founding fathers of modern logic. Yet, according to a challenging interpretation proposed by Patricia Blanchette, Frege's conception of logic is, in a...

ABSTRACT Leśniewskian Ontology (LO) is a system in which the basic subject-predicate formula takes the form of a b and express one-argument predication, e.g. John is a student. In LO’s language, there is no many-argument form of predication given that would allow for the structural expression of, for example, the sentence John is Anne’s son. In this article, a simple and natural extension of LO is suggested to encompass many-argument predication. The system thus obtained corresponds to polyadic second-order logic.

Understanding what is the strictly formal import of Hegel's view is something on which few analytic philosophers have seen time worth spending. Still in our view there is enough in Hegel's work to suggest that a formal account of his dialectial process might be profitable both for better understanding Hegel's ideas and for introducing a new sort of glutty logic. The focus of our analysis is Hegel's Conjunction, which, in our view, is the crucial dialectical operation, on which all others (...) are ultimately based. (shrink)

Hegel’s approach to soritical arguments (as well as to paradoxes in general) can be read as a kind of conjunctive paraconsistency: the ‘explosive’ effect of contradictions is avoided by assuming ‘the unity of the opposites’, so that contradictory conjunctions are not simplifiable. The paper reconsiders what Hegel says about the Sorites and justifies the conjunctive interpretation. The first section introduces the analysis, presenting the role of the Einheit Entgegengesetzter for contemporary theories of paradoxes. In the second section, the focus is (...) on Hegel’s interpretation of the Sorites. The third section briefly considers some contemporary accounts of vagueness in the light of Hegel’s view so reconstructed. The last section summarizes the main results and explores some ideas about how to formalize a Hegel-inspired conjunctive view. (shrink)

The idea at the basis of this special issue is that reopening the old debate about the logical status of Hegel's dialectics is extremely interesting, for various reasons. The first reason is that a new Hegel is circulating, nowadays, in the philosophical literature, with specific reference to Hegel's dialectical logic and its relation to the history and philosophy of logic. This development deserves to be accounted for. Secondly, new research about the connection between contradictory logical systems and Hegel's dialectics is (...) also being developed, and this too deserves to be acknowledged. Finally there are, recently, confirmations that the concept of dialectics is of general interest, and that the usual perplexities about the Hegelian triadic and fairly mechanic device of ‘yes, not, and not not’ are in remission. (shrink)

Hegel’s Doctrine of the Concept advances a theory of conceptual determinacy. As I will demonstrate, Hegel’s theory of conceptual determinacy leads him to endorse self-predication and existential implication as features endemic to conceptual content. I first demonstrate some features of this logic, and some of its entailments. Following the reconstruction of Hegel’s logic of self-predication, I apply this logic to illuminate Hegel’s critique of formal logic. Finally, the self-predicative feature of Hegel’s logics offers a measure by which to determine the (...) potential and the limitations of any formal account of Hegel’s logic. (shrink)

This essay addresses the general systematic question underlying any project of ‘formalization’ of Hegel’s dialectic-speculative logic, namely, the question concerning the peculiar concept of logical ‘form’ and the connected type of ‘formalism’ at stake in a logic that is, programmatically and innovatively within the historical tradition, a ‘dialectic-speculative’ logic.

Gotthard Günther's early work is inspired by Hegel's logic. Both share the view that the forms of ‘classical logic’ are insufficient to capture essential aspects of thought. However, while Hegel rules out formalization for his dialectical logic, Günther attributes this to the fact that Hegel's thought itself is still bound to the forms of a classical logic. Günther thus develops a trans-classical logic, with which he believes he can formally capture some of Hegel's insights. The paper presents Günther’s critical engagement (...) with Hegel and outlines some basic assumptions arising from his critique. (shrink)

I give a formal model of dialectical progression, as found in Hegel and Marx. The model is outlined in the first half of the paper, and deploys the tools of a formal paraconsistent logic. In the second half, I discuss a number of examples of dialectical progressions to be found in Hegel and Marx, showing how they fit the model.

Hegel interpreters commonly reject attempts to situate Hegel’s logic in relation to modern movements. Appealing to his criticisms of the logic of Verstand or mere understanding with its fixed logical structure, Hegel’s logic, it is pointed out, was a logic of Vernunft or reason—a logic more at home in the thought of Plato and Aristotle than in modern mathematical forms. Contesting this implied dichotomy, it is here argued that the ancient roots of Hegel’s logic, especially as transmitted by late Neopythagorean/Neoplatonic (...) thinkers such as Proclus, gave it many features similar to ones later found in the type of algebraic transformation of Aristotle, started first by Leibniz, reanimated by Boole in the mid-nineteenth century and then developed by others such as C. S. Peirce and Arend Heyting. In particular, the ancient mathematics upon which Hegel had drawn allowed him to anticipate an answer to the criticism that Frege would later aim at Boole, concerning his inability to unite opposed class and propositional calculi. Hegel’s logic would be a hybrid, incorporating features found later in intuitionist and classical logic, but it could be so because of the way he had called upon the mathematics of the ancient Platonist tradition. (shrink)

This paper aims at disentangling two distinct problems in present philosophy of logic: the a priori/a posteriori divide and the theory choice problem. A confusion of these problems is present in the heart of current anti-exceptionalism about logic, as the use of a posteriori methods is identified with theory choice. We illustrate how the division may be preserved in a version of anti-exceptionalism by discussing Carnap’s approach, which had both an a priori epistemology and a pragmatic account of logical theory (...) choice. This contributes to illuminate the claim that the current understanding is mistaken in considering Carnap as an exceptionalist, and it also helps us to address one of the difficulties of current anti-exceptionalism, to know, that, by equating a posteriori with theory choice, it requires appeal to framework-independent facts. We suggest that the pragmatic account of both Quine and Carnap to theory choice was advanced precisely to avoid that kind of difficulty. (shrink)

In the Laws of Thought, Boole establishes a theory of secondary propositions based upon the notion of time. This temporal interpretation of secondary propositions has historically been met with wide disapproval and is usually dismissed in the modern literature as a philosophical non-starter. What was Boole thinking? This paper attempts to give an answer to this question. Specifically, it provides an account according to which Boole’s temporal interpretation follows from his psychologistic conception of logic, in addition to certain background assumptions (...) regarding the psychological necessity of the concept of time. Once Boole’s psychological premises are laid bare, it becomes clearer how he might have viewed the temporal interpretation to be an essential feature of his theory of secondary propositions. (shrink)

In La Silogística de Aristóteles, Antonio Benítez (i) offers a critical analysis of two contemporary interpretations of Aristotle's syllogistic of assertoric propositions (Corcoran and Łukasiewicz), and (ii) proposes to demonstrate the benefits of a mereological interpretation of the non-modal Aristotelian syllogistic.

This book presents a (new) attempt to apply the notion of an underlying logic to Aristotle’s Organon and certain passages of the Metaphysics. The author situates his approach as part of a ‘deductio...