The Inadequacy of a Proposed Paraconsistent Set Theory (original) (raw)

Paraconsistent set theory by predicating on consistency

2016

This article intends to contribute to the debate about the uses of paraconsistent reasoning in the foundations of set theory, by means of using the logics of formal inconsistency and by considering consistent and inconsistent sentences, as well as consistent and inconsistent sets. We establish the basis for new paraconsistent set-theories (such as ZFmbC and ZFCil) under this perspective and establish their non-triviality, provided that ZF is consistent. By recalling how George Cantor himself, in his efforts towards founding set theory more than a century ago, not only used a form of ‘inconsistent sets’ in his mathematical reasoning, but regarded contradictions as beneficial, we argue that Cantor's handling of inconsistent collections can be related to ours.

S.: 2001, ’A critical study on the concept of identity in Zermelo-Fraenkel-like axioms

2001

According to Cantor, a set is a collection into a whole of defined and separate (we shall say distinct) objects. So, a natural question is “How to treat as ‘sets ’ collections of indistinguishable objects?”. This is the aim of quasi-set theory, and this problem was posed as the first of present day mathematics, in the list resulting from the Congress on the Hilbert Problems in 1974. Despite this pure mathematical motivation, quasi-sets have also a strong commitment to the way quantum physics copes with elementary particles. In this paper, we discuss the axiomatics of quasi-set theory and sketch some of its applications in physics. We also show that quasi-set theory allows us a better and deeper understanding of the role of the concept of equality in mathematics. 1

A critical study on the concept of identity in Zermelo-Fraenkel-like axioms

2001

According to Cantor, a set is a collection into a whole of defined and separate (we shall say distinct) objects. So, a natural question is ``How to treat as `sets' collections of indistinguishable objects?". This is the aim of quasi-set theory, and this problem was posed as the first of present day mathematics, in the list resulting from the Congress on the Hilbert Problems in 1974. Despite this pure mathematical motivation, quasi-sets have also a strong commitment to the way quantum physics copes with elementary particles. In this paper, we discuss the axiomatics of quasi-set theory and sketch some of its applications in physics. We also show that quasi-set theory allows us a better and deeper understanding of the role of the concept of equality in mathematics.

Paraconsistent Metatheory: New Proofs with Old Tools

Journal of Philosophical Logic, 2022

This paper is a step toward showing what is achievable using non-classical metatheory—particularly, a substructural paraconsistent framework. What standard results, or analogues thereof, from the classical metatheory of first order logic(s) can be obtained? We reconstruct some of the originals proofs for Completeness, Löwenheim-Skolem and Compactness theorems in the context of a substructural logic with the naive comprehension schema. The main result is that paraconsistent metatheory can ‘re-capture’ versions of standard theorems, given suitable restrictions and background assumptions; but the shift to non-classical logic may recast the meanings of these apparently ‘absolute’ theorems.

Models for da Costa’s paraconsistent set theory

Anais do Workshop Brasileiro de Lógica (WBL 2020), 2020

In this work we will be constructed F-structures-valued models as generalization of Boolean-valued models and proved that these models that verify Leibniz’ Law validate all the set-theoretic axioms of da Costa’s Paraconsistent Set Theory type ZF.

Remarks on Paraconsistency and Contradiction

In this paper we propose to take seriously the claim that at least some kinds of paraconsistent negations are subcontrariety forming operators. We shall argue that from an intuitive point of view, by considering paraconsistent negations that way, one needs not worry with true contradictions and the like, given that "true contradictions" are not involved in these paraconsistent logics. Our strategy consists in showing that the natural translation for subcontrariety in formal languages is not a contradiction in natural language, and vice versa. This move shall provide for an intuitive interpretation for paraconsistent negation, which we also discuss here. By putting all those pieces together, we hope a clearer sense of paraconsistency can be made, one which may free us from the need to tame contradictions.

LAMBDA THEORY: INTRODUCTION OF A CONSTANT FOR “NOTHING ” INTO SET THEORY, A MODEL OF CONSISTENCY AND MOST NOTICEABLE CONCLUSIONS

The purpose of this article is to present several immediate consequences of the introduction of a new constant called Lambda in order to represent the object "nothing" or "void" into a standard set theory. The use of Lambda will appear natural thanks to its role of condition of possibility of sets. On a conceptual level, the use of Lambda leads to a legitimation of the empty set and to a redefinition of the notion of set. It lets also clearly appear the distinction between the empty set, the nothing and the ur-elements. On a technical level, we introduce the notion of pre-element and we suggest a formal definition of the nothing distinct of that of the null-class. Among other results, we get a relative resolution of the anomaly of the intersection of a family free of sets and the possibility of building the empty set from "nothing". The theory is presented with equi-consistency results (model and interpretation). On both conceptual and technical levels, the introduction of Lambda leads to a resolution of the Russell's puzzle of the null-class.