Pragmatic Nonsense

Inspired by the early Wittgenstein's concept of nonsense (meaning that which lies beyond the limits of language), we define two different, yet complementary, types of nonsense: formal nonsense and pragmatic nonsense. The simpler notion of formal nonsense is initially defined within Tarski's semantic theory of truth; the notion of pragmatic nonsense, by its turn, is formulated within the context of the theory of pragmatic truth, also known as quasi-truth, as formalized by da Costa and his collaborators. While an expression will be considered formally nonsensical if the formal criteria required for the assignment of any truth-value (whether true, false, pragmatically true, or pragmatically false) to such sentence are not met, a (well-formed) formula will be considered pragmatically nonsensical if the pragmatic criteria (inscribed within the context of scientific practice) required for the assignment of any truth-value to such sentence are not met. Thus, in the context of the theory of pragmatic truth, any (well-formed) formula of a formal language interpreted on a simple pragmatic structure will be considered pragmatically nonsensical if the set of primary sentences of such structure is not well-built, that is, if it does not include the relevant observational data and/or theoretical results, or if it does include sentences that are inconsistent with such data

The simplicity bubble effect as a zemblanitous phenomenon in learning systems

The ubiquity of Big Data and machine learning in society evinces the need of further investigation of their fundamental limitations. In this paper, we extend the ``too-much-information-tends-to-behave-like-very-little-information'' phenomenon to formal knowledge about lawlike universes and arbitrary collections of computably generated datasets. This gives rise to the simplicity bubble problem, which refers to a learning algorithm equipped with a formal theory that can be deceived by a dataset to find a locally optimal model which it deems to be the global one. However, the actual high-complexity globally optimal model unpredictably diverges from the found low-complexity local optimum. Zemblanity is defined by an undesirable but expected finding that reveals an underlying problem or negative consequence in a given model or theory, which is in principle predictable in case the formal theory contains sufficient information. Therefore, we argue that there is a ceiling above which formal knowledge cannot further decrease the probability of zemblanitous findings, should the randomly generated data made available to the learning algorithm and formal theory be sufficiently large in comparison to their joint complexity

The completeness and compactness of a three-valued first-order logic

The strong completeness and the compactness of a three-valued first order predicate calculus with two distinguished truth-values are obtained. The system was introduced in Sur un prcb leme de Jaskowski, I .M.L. D.'Ottaviano and N.C. A. da Costa, C.R. Acad.Sc. Paris 270A (1970) , pp.1349-1353, and has several applications, especially in paraconsistent logics

Aristotle´s Theory of Deduction and Paraconsistency

In the Organon Aristotle describes some deductive schemata in which inconsistencies do not entail the trivialization of the logical theory involved. This thesis is corroborated by three different theoretical topics by him discussed, which are presented in this paper. We analyse inference schema used by Aristotle in the Protrepticus and the method of indirect demonstration for categorical syllogisms. Both methods exemplify as Aristotle employs classical reductio ad absurdum strategies. Following, we discuss valid syllogisms from opposite premises (contrary and contradictory) studied by the Stagerian in the Analytica Priora (B15). According to him, the following syllogisms are valid from opposite premises, in which small Latin letters stand for terms such as subject and predicate, and capital Latin letters stand for the categorical propositions such as in the traditional notation: (i) in the second ?gure, E ba, Aba ` Eaa (Cesare), Aba, E ba ` Eaa (Camestres), E ba, I ba ` Oaa (Festino), and Aba, Oba ` Oaa (Baroco); (ii) in the third one, Eab, Aab ` Oaa (Felapton), Oab, Aab ` Oaa (Bocardo) and Eab, I ab ` Oaa (Ferison). Finally, we discuss the passage from the Analytica Posteriora (A11) in which Aristotle states that the Principle of Non-Contradiction is not generally presupposed in all demonstrations (scienti?c syllogisms), but only in those in which the conclusion must be proved from the Principle; the Stagerian states that if a syllogism of the ?rst ?gure has the major term consistent, the other terms of the demonstration can be each one separately inconsistent. These results allow us to propose an interpretation of his deductive theory as a broad sense paraconsistent theory. Firstly, we proceed to a hermeneutical analysis, evaluating its logical signi?cance and the interplay of the results with some other points of Aristotle�s philosophy. Secondly, we point to a logical interpretation of the Aristotelian syllogisms from opposite premises in the antilogisms method proposed by Christine Ladd-Franklin in 1883, and we also present a logical treatment of the Aristotelian demonstration with inconsistent material in the paraconsistent logics Cn , 1 n !, introduced by da Costa in 1963. These two issues seem having not yet been analysed in detail in the literature

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