By a comparison between Maxwell's electrodynamics classically interpreted (MT) and relativistic electrodynamics (RED), this paper discusses whether the “asymmetries” in MT mentioned by A. Einstein in his 1905 relativity paper are only of a conceptual nature or rather involve specific empirical claims. It is shown that in fact MT predicts strongly asymmetric behaviour for very simple interactions, and an analysis is made of the extent of the “symmetry” achieved by means of relativistic postulates. A “low” velocity experiment is suggested which (...) could provide another test of the accuracy of RED with respect to MT. (shrink)

La crisi dello strutturalismo e i confini della semiotica in un volume importante della produzione di Eco. Un libro che trova la sua continuazione ideale in 'Lector in fabula'.

This paper provides a philosophical analysis and a new edition of an anonymous Epitome of John Dumbleton’s solution to the semantic paradoxes. The first part of this paper briefly presents Dumbleton’s cassationist solution to the semantic paradoxes, which the English philosopher proposes in his Summa Logicae, written in the 1330s–40s. The second part investigates the solution to various types of insolubles proposed by the anonymous author of the Epitome. The third part provides a new critical edition of the Latin text (...) – a first edition was edited by Bottin in 1978 – and an English translation. (shrink)

On the Shoulders of Giants collects previously unpublished essays from the last fifteen years of Umberto Eco's life. With humor and erudition, one of the great contemporary thinkers takes on the roots of Western culture, the origin of language, the nature of beauty and ugliness, the imperfections of art, and the lure of mysteries.

La conoscenza che abbiamo del testo del Libellus ad Leonem X, noto anche come De Officio Pontificis ad Leonem X, redatto dai camaldolesi veneziani Tommaso Giustiniani e Vincenzo Querini , ruota intorno al codice che “extabat MS in Bibliotheca Monasterii S. Mariae Carcerum, nunc in Bibliotheca S. Michaelis Muriani”1 identificabile con il manoscritto Muraniano 1071, oggi conservato presso la Biblioteca del Monastero di Camaldoli.2 Si tratta del codice che è stato utilizzato, secondo quanto dichiarato dallo stesso Mittarelli,3 dai camaldolesi Giovanni (...) Benedetto Mittarelli e Anselmo Costadoni 4 per la loro edizione negli Annales Camaldulenses.5 Vi è una notazione .. (shrink)

A literary prank leads to deadly danger in this “endlessly diverting” intellectual thriller by the author of The Name of the Rose (Time). Bored with their work, three Milanese book editors cook up an elaborate hoax that connects the medieval Knights Templar with occult groups across the centuries. Becoming obsessed with their own creation, they produce a map indicating the geographical point from which all the powers of the earth can be controlled—a point located in Paris, France, at Foucault’s Pendulum. (...) But in a fateful turn the joke becomes all too real. When occult groups, including Satanists, get wind of the Plan, they go so far as to kill one of the editors in their quest to gain control of the earth. Orchestrating these and other diverse characters into his multilayered semiotic adventure, Umberto Eco has created a superb cerebral entertainment. "An intellectual adventure story…sensational, thrilling, and packed with arcana."—The Washington Post Book World. (shrink)

Recent years have yielded many discussions on how to endow autonomous agents with the ability to make ethical decisions, and the need for explicit ethical reasoning and transparency is a persistent theme in this literature. We present a modular and transparent approach to equip autonomous agents with the ability to comply with ethical prescriptions, while still enacting pre-learned optimal behaviour. Our approach relies on a normative supervisor module, that integrates a theorem prover for defeasible deontic logic within the control loop (...) of a reinforcement learning agent. The supervisor operates as both an event recorder and an on-the-fly compliance checker w.r.t. an external norm base. We successfully evaluated our approach with several tests using variations of the game Pac-Man, subject to a variety of “ethical” constraints. (shrink)

pt. 1. Dal nichilismo alla dignità dell'uomo. -- [pt. 2]. Esistenza e sacro.

In preference aggregation a set of individuals express preferences over a set of alternatives, and these preferences have to be aggregated into a collective preference. When preferences are represented as orders, aggregation procedures are called social welfare functions. Classical results in social choice theory state that it is impossible to aggregate the preferences of a set of individuals under different natural sets of axiomatic conditions. We define a first-order language for social welfare functions and we give a complete axiomatisation for (...) this class, without having the number of individuals or alternatives specified in the language. We are able to express classical axiomatic requirements in our first-order language, giving formal axioms for three classical theorems of preference aggregation by Arrow, by Sen, and by Kirman and Sondermann. We explore to what extent such theorems can be formally derived from our axiomatisations, obtaining positive results for Sen’s Theorem and the Kirman-Sondermann Theorem. For the case of Arrow’s Theorem, which does not apply in the case of infinite societies, we have to resort to fixing the number of individuals with an additional axiom. In the long run, we hope that our approach to formalisation can serve as the basis for a fully automated proof of classical and new theorems in social choice theory. (shrink)

Antonio Rosmini is considered by many to be greatest Italian - or even European - thinker of the nineteenth century. But for christians he is also a saint. Here, marking ten years since his beatification in 2007, is an updated biography.

We look at extensions (i.e., stronger logics in the same language) of the Belnap–Dunn four-valued logic. We prove the existence of a countable chain of logics that extend the Belnap–Dunn and do not coincide with any of the known extensions (Kleene’s logics, Priest’s logic of paradox). We characterise the reduced algebraic models of these new logics and prove a completeness result for the first and last element of the chain stating that both logics are determined by a single finite logical (...) matrix. We show that the last logic of the chain is not finitely axiomatisable. (shrink)

This is the second of a series of papers that investigate fragments of quasi-Nelson logic (QNL) from an algebraic logic standpoint. QNL, recently introduced as a common generalization of intuitionistic and Nelson’s constructive logic with strong negation, is the axiomatic extension of the substructural logic |$FL_{ew}$| (full Lambek calculus with exchange and weakening) by the Nelson axiom. The algebraic counterpart of QNL (quasi-Nelson algebras) is a class of commutative integral residuated lattices (a.k.a. |$FL_{ew}$|-algebras) that includes both Heyting and Nelson algebras (...) and can be characterized algebraically in several alternative ways. The present paper focuses on the algebraic counterpart (a class we dub quasi-Nelson implication algebras, QNI-algebras) of the implication–negation fragment of QNL, corresponding to the connectives that witness the algebraizability of QNL. We recall the main known results on QNI-algebras and establish a number of new ones. Among these, we show that QNI-algebras form a congruence-distributive variety (Cor. 3.15) that enjoys equationally definable principal congruences and the strong congruence extension property (Prop. 3.16); we also characterize the subdirectly irreducible QNI-algebras in terms of the underlying poset structure (Thm. 4.23). Most of these results are obtained thanks to twist representations for QNI-algebras, which generalize the known ones for Nelson and quasi-Nelson algebras; we further introduce a Hilbert-style calculus that is algebraizable and has the variety of QNI-algebras as its equivalent algebraic semantics. (shrink)