Stephen Read has presented an argument for the inconsistency of the concept of validity. We extend Read’s results and show that this inconsistency is but one half of a larger problem. Like the concept of truth, validity is infected with what we call semantic pathology, a condition that actually gives rise to two symptoms: inconsistency and indeterminacy. After sketching the basic ideas behind semantic pathology and explaining how it manifests both symptoms in the concept of truth, we present cases that (...) establish the indeterminacy of validity and that link this indeterminacy with the concept’s inconsistency. Our conclusion is that an adequate treatment of the semantic pathology thus revealed must deal with both of its symptoms. Further, it must extend to the occurrences of this condition elsewhere: in the concept of truth, in the other central semantic notions, and even in certain philosophical concepts outside semantics. (shrink)

The ?no???no? paradox (so-called by Sorensen) consists of a pair of propositions each of which says of the other that it is false. It is not immediately paradoxical, since it has a solution in which one proposition is true, the other false. However, that is itself paradoxical, since there is no clear ground for determining which is which. The two propositions should have the same truth-value. The paper shows how a proposal by the medieval thinker Thomas Bradwardine solves not only (...) the Liar paradox, but also symmetric paradoxes like the ?no???no?, the descending ?no???no?, and the Truth-teller paradoxes. (shrink)

An instantia is a technique to refute other's arguments, found in many tracts from the latter half of the twelfth century. An instantia has (or appears to have) the same form as the argument to be refuted and its falsity is more evident than that of the argument.Precursors of instantiae are among the teachings of masters active in the first half of the century. These masters produce counter-arguments against various inferential forms in order to examine their validity. But the aim (...) of producing counter-arguments change in the latter half of the century into refuting other's arguments to win in debate by any means available. Logicians of that period do not care whether the counter-arguments (instantiae) are sophistical or not, viz. the falsity of instantiae is or is not due to the flaw common to the argument to be refuted.Many instantiae they produce involve logical entanglements into which they themselves have little clear insight. Some instantiae and the attempts to explain them grows into the new theories in the “terminist texts” around 1200 A.D., when instantia literature itself disappears. Some instantiae and the issues they raise have no place in terminist texts, and sink into oblivion. (shrink)

Scholastic and analytic definitions of semantic paradoxes, in terms of groundlessness, circularity, and semantic pathology, are introduced and compared with each other. The fundamental intuitions used in these definitions are the concepts of being true about extralinguistic reality, of making statements about one’s self, and of compatibility with an underlying semantic theory. The three approaches—the groundlessness view, the circularity view, and the semantic pathology view—are shown to differ not only conceptually, but also in their applications. As both a means for (...) showing these differences and as an adequacytest, the so-called two-line puzzles are used, which allows one to address the possibility of making non-paradoxical statements about paradoxical sentences within the same language. (shrink)

A syntactically correct number-specification may fail to specify any number due to underspecification. For similar reasons, although each sentence in the Yablo sequence is syntactically perfect, none yields a statement with any truth-value. As is true of all members of the Liar family, the sentences in the Yablo sequence are so constructed that the specification of their truth-conditions is vacuous; the Yablo sentences fail to yield statements. The ‘revenge’ problem is easily defused. The solution to the semantical paradoxes offered here (...) revives the mediaeval cassatio approach, one that largely disappeared due to its incomprehending rejection by influential contemporary writers such as William Shyreswood and Thomas Bradwardine. The diagnosis readily extends to the set-theoretic paradoxes. (shrink)

An eleventh-century Greek text, in which a fourth-century patristic text is discussed, gives an outline of a solution to the Liar Paradox. The eleventh-century text is probably the first medieval treatment of the Liar. Long passages from both texts are translated in this article. The solution to the Liar Paradox, which they entail, is analysed and compared with the results of modern scholarship on several Latin solutions to this paradox. It is found to be a solution, which bears some analogies (...) to contemporary game semantics. Further, an overview of other Byzantine scholia on the Liar Paradox is provided. The findings and the originality of the discussed solution to the Liar Paradox suggest a change in the way in which Byzantine Logic is traditionally regarded in contemporary scholarship. (shrink)

Two periods in the history of logic and philosophy are characterized notably by vivid interest in self-referential paradoxical sentences in general, and Liar sentences in particular: the later medieval period (roughly from the 12th to the 15th century) and the last 100 years. In this paper, I undertake a comparative taxonomy of these two traditions. I outline and discuss eight main approaches to Liar sentences in the medieval tradition, and compare them to the most influential modern approaches to such sentences. (...) I also emphasize the aspects of each tradition that find no counterpart in the other one. It is expected that such a comparison may point in new directions for future research on the paradoxes; indeed, the present analysis allows me to draw a few conclusions about the general nature of Liar sentences, and to identify aspects that would require further investigation. (shrink)

O presente artigo pretende inserir o teólogo franciscano Geraldo Odon no debate historiográfico medieval acerca das diferentes soluções oferecidas ao célebre paradoxo do mentiroso. Na primeira parte a autora apresenta rapidamente e de forma esquemática os principais tipos de solução ao sofisma para em seguida analisar o texto de Odon, respondendo à questão da sua originalidade.