Logic and Logical Philosophy 2021-07-18T23:26:45+02:00 Andrzej Pietruszczak Open Journal Systems <p><em>Logic and Logical Philosophy</em> is a journal chiefly devoted to philosophical logic and philosophy resulting from applying logical tools to philosophical problems. Other applications of logic to related disciplines are not excluded.</p><p>Beginning with 2016, <em>Logic and Logical Philosophy</em> is being indexed and abstracted in Emerging Sources Citation Index (Web of Science) in Clarivate Analytics products and services (<a href=";ISSN=1425-3305">Web of Science Master Journal List</a>). <em>LLP</em> is included in categories: philosophy and logic.</p><p>Clarivate Analytics launches a new Journal Citation Indicator (JCI) for the year 2020. JCI has been published in the 2020 Journal Citation Reports<span> (JCR)</span>. JCI index for <em>LLP</em> is 1.25. This value gives <em>LLP</em> (<a href=";year=2020&amp;fromPage=%2Fjcr%2Fbrowse-journals&amp;SID=H3-JZyy6gg7XqbrX5s9l8oMfmuhCMBGuuKX-18x2dCrI6CaTt8clTPTpUU0DGKQx3Dx3DI5vvpjan6wPorHx2B3Pa4tWwx3Dx3D-WwpRYkX4Gz8e7T4uNl5SUQx3Dx3D-wBEj1mx2B0mykql8H4kstFLwx3Dx3D">link</a>): <br /> • the second place in the category of logic: JCI rank 2/25, JCI quartile Q1, JCI percentile 94.00; <br /> • the 59th place in the category of philosophy: JCI rank 59/314, JCI quartile Q1, JCI percentile 81.37.</p><p><em>Logic and Logical Philosophy</em> has been indexed in the Scopus database since 2011. According to their 2020 results:<br /> • Scopus CiteScore™ gives <em>LLP</em> a CiteScore™ <span>80th percentile</span> for a journal of philosophy (<a href="">link</a>);<br /> • Scimago Journal Rank (SJR) has determined that <em>LLP</em> has status Q1 for a journal of philosophy (place 9 among <span>open access </span>journals) <a href=";tip=sid&amp;clean=0"> (link)</a>;<br /> • The CWTS Journal Indicator SNIP (Source Normalized Impact for Publication) for <em>LLP</em> is 1.1 (<a href="">link</a>). This index placed <em>LLP</em> among 20 per cent of the best journals of philosophy.</p> States of Affairs as Structured Extensions in Free Logic 2021-07-18T23:26:43+02:00 Hans-Peter Leeb The search for the extensions of sentences can be guided by Frege’s “principle of compositionality of extension”, according to which the extension of a composed expression depends only on its logical form and the extensions of its parts capable of having extensions. By means of this principle, a strict criterion for the admissibility of objects as extensions of sentences can be derived: every object is admissible as the extension of a sentence that is preserved under the substitution of co-extensional expressions. The question is: what are the extensions of elementary sentences containing empty singular terms, like ‘Vulcan rotates’. It can be demonstrated that in such sentences, states of affairs as structured objects (but not truth-values) are preserved under the substitution of co-extensional expressions. Hence, such states of affairs are admissible (while truth-values are not) as extensions of elementary sentences containing empty singular terms. 2020-12-28T00:00:00+01:00 Copyright (c) 2020 Logic and Logical Philosophy Modal multilattice logics with Tarski, Kuratowski, and Halmos operators 2021-07-18T23:26:43+02:00 Oleg Grigoriev Yaroslav Petrukhin <div><p class="Standard">In this paper, we consider modal multilattices with Tarski, Kuratowski, and Halmos closure and interior operators as well as the corresponding logics which are multilattice versions of the modal logics MNT4, S4, and S5, respectively. The former modal multilattice logic is a new one. The latter two modal multilattice logics have been already mentioned in the literature, but algebraic completeness results have not been established for them before. We present a multilattice version of MNT4 in a form of a sequent calculus and prove the algebraic and neighbourhood completeness theorems for it. We extend the algebraic completeness result for the multilattice versions of S4 and S5 as well.</p></div> 2021-02-20T00:00:00+01:00 Copyright (c) 2021 Logic and Logical Philosophy A Syntactical Analysis of Lewis’s Triviality Result 2021-07-18T23:26:43+02:00 Claudio E. A. Pizzi <p>The first part of the paper contains a probabilistic axiomatic extension of the conditional system WV, here named WVPr. This system is extended with the axiom (Pr4): PrA = 1 ⊃ □A. The resulting system, named WVPr∗, is proved to be consistent and non-trivial, in the sense that it does not contain the wff (Triv): A ≡□A. Extending WVPr∗ with the so-called Generalized Stalnaker’s Thesis (GST) yields the (first) Lewis’s Triviality Result (LTriv) in the form (◊(A ∧ B) ∧◊(A ∧ ¬B)) ⊃ PrB|A = PrB. In §4 it is shown that a consequence of this theorem is the thesis (CT1): ¬A ⊃ (A &gt; B ⊃ A ⥽ B). It is then proven that (CT1) subjoined to the conditional system WVPr∗ yields the collapse formula (Triv). The final result is that WVPr∗+(GST) is equivalent to WVPr∗+(Triv). In the last section a discussion is opened about the intuitive and philosophical plausibility of axiom (Pr4) and its role in the derivation of (Triv).</p> 2021-03-24T00:00:00+01:00 Copyright (c) 2021 Logic and Logical Philosophy Extension and Self-Connection 2021-07-18T23:26:44+02:00 Ben Blumson Manikaran Singh <p class="p1">If two self-connected individuals are connected, it follows in classical extensional mereotopology that the sum of those individuals is self-connected too. Since mainland Europe and mainland Asia, for example, are both self-connected and connected to each other, mainland Eurasia is also self-connected. In contrast, in non-extensional mereotopologies, two individuals may have more than one sum, in which case it does not follow from their being self-connected and connected that the sum of those individuals is self-connected too. Nevertheless, one would still expect it to follow that a sum of connected self-connected individuals is self-connected too. In this paper, we present some surprising countermodels which show that this conjecture is incorrect.</p> 2021-05-18T00:00:00+02:00 Copyright (c) 2021 Logic and Logical Philosophy Nicolai Hartmann and the Transcendental Method 2021-07-18T23:26:44+02:00 Alicja Pietras One of the most often explored, repeatedly interpreted, and recognized again and again as a valuable achievement of Kant’s philosophy, is his transcendental philosophy, a new methodological approach that – as Kant believed – will allow philosophy (metaphysics) to enter upon a secure path of science. In this paper, I explore Nicolai Hartmann’s reinterpretation and development of this methodology in both the historical and systematic context of his thought. First, I will deal with the Neo-Kantian’s understanding of the transcendental method as a starting point of Hartmann’s own understanding of it. Then I will analyze in detail his only paper devoted entirely to the problem of the method, (Hartmann, 1912), to present how he understands the necessary development of this methodology. I will claim that despite the fact that Hartmann – following Kant – never denied that the real essence of philosophy is the transcendental method, he tried to show that this <em>methodus philosophandi</em> cannot be reduced to the Neo-Kantian’s understanding of it. He argued that the core of all true philosophical and scientific research is the transcendental method, but only insofar as it is accompanied by two other methods that are needed to complete it: descriptive and dialectical method. I will close by presenting the relations between these three methods. 2021-01-12T00:00:00+01:00 Copyright (c) 2021 Logic and Logical Philosophy Normalisation for Some Quite Interesting Many-Valued Logics 2021-07-18T23:26:44+02:00 Nils Kürbis Yaroslav Petrukhin In this paper, we consider a set of quite interesting three- and four-valued logics and prove the normalisation theorem for their natural deduction formulations. Among the logics in question are the Logic of Paradox, First Degree Entailment, Strong Kleene logic, and some of their implicative extensions, including RM<sub>3</sub> and RM<sub>3</sub><sup>⊃</sup>. Also, we present a detailed version of Prawitz’s proof of Nelson’s logic N4 and its extension by intuitionist negation. 2021-06-16T00:00:00+02:00 Copyright (c) 2021 Logic and Logical Philosophy Peirce’s Triadic Logic and Its (Overlooked) Connexive Expansion 2021-07-18T23:26:45+02:00 Alex Belikov <p>In this paper, we present two variants of Peirce’s Triadic Logic within a language containing only conjunction, disjunction, and negation. The peculiarity of our systems is that conjunction and disjunction are interpreted by means of Peirce’s mysterious binary operations Ψ and Φ from his ‘Logical Notebook’. We show that semantic conditions that can be extracted from the definitions of Ψ and Φ agree (in some sense) with the traditional view on the semantic conditions of conjunction and disjunction. Thus, we support the conjecture that Peirce’s special interest in these operations is due to the fact that he interpreted them as conjunction and disjunction, respectively. We also show that one of our systems may serve as a suitable base for an interesting implicative expansion, namely the connexive three-valued logic by Cooper. Sound and complete natural deduction calculi are presented for all systems examined in this paper.</p> 2021-05-02T00:00:00+02:00 Copyright (c) 2021 Logic and Logical Philosophy