Formulações da validade dedutiva clássica costumam recorrer explicitamente a modalidades: por exemplo, um argumento é classicamente dedutivamente válido se, e somente se, necessariamente se as premissas forem verdadeiras, a conclusão também é verdadeira. Não é possível abolir completamente esse apelo ao discurso modal, porque a lógica clássica é o domínio das possibilidades. Não obstante, pode-se, por intermédio de uma semântica informacional, evitar que o usuário da lógica clássica tenha de manipular modalidades, ainda que elas estejam, de algum modo, imbricadas nos (...) infons – unidades mínimas de informação. A partir do trabalho pioneiro de Carnap e de Bar-Hillel, apresentarei duas semânticas informacionais: uma delas diretamente relacionada a mundos possíveis, e a outra relacionada aos duais de mundos possíveis. (shrink)

Parmenides and Melissus employ different deductive styles for their different kinds of argumentation. The former’s poem flows in an interesting sequence of passages: contents foreword, methodological premises, krisis, conclusions and corollaries. The latter, however, organizes an extensive process of deduction to show the characteristics of what is. In both cases, the strength of their argument rests on their deductive form, on the syntactical level of their texts: the formal structure of their reasonings help to identify the features and logical intersections (...) of their thoughts. On the one hand, Parmenides uses modal reasoning, enforcing the employment of the principle of the excluded middle. On the other hand, Melissus radicalizes the use of modal reasoning and employs counterfactual statements in order to develop his doctrine of what is. Despite their differences, both deserve a place in the Stone Age of logic and theory of argumentation due to their common ambition to demonstrate what is. (shrink)

This page is dedicated to an analysis of the first section of Parmenides' Poem, the Way of Truth, with a selection of critical judgments by the most important commentators and critics. In the Annotated Bibliography I list the main critical editions (from the first printed edition of 1573 to present days) and the translations in English, French, German, Italian and Spanish, with a selection of studies on Parmenides; in future, a section will be dedicated to an examination of some critical (...) variants of the Greek text, with particular attention to corrections to the Diels-Kranz (abbreviated DK) edition of the Fragmente der Vorsokratiker. The fragments of Parmenides' Poem are cited according to Diels-Kranz numbering system as adopted in the 6th edition, Berlin 1952; the Poem is divided into three parts: the Proem fr. I, 1-32; the Way of Truth (Alethéia) from fr. II to VIII, 49, and the Way of Mortal Opinion (Doxa) fr. VIII, 50 to XIX, 3. (shrink)

The primary interpretative challenge for understanding Parmenides’ poem revolves around explaining both the meaning of, and the relationship between, its two primary sections: a) the positively endorsed metaphysical arguments which describe some unified, unchanging, motionless, and eternal “reality”, and b) the ensuing cosmology, which incorporates the very principles explicitly denied in Aletheia. I will refer to this problem as the “A-D Paradox.” I advocate resolving this paradoxical relationship by reading Parmenides’ poem as a ring-composition, and incorporating a modified version of (...) Palmer’s modal interpretation of Aletheia. On my interpretation, Parmenides’ thesis in Aletheia is not a counter-intuitive description of how all the world must truly be, but rather a radical rethinking of divine nature. Understanding Aletheia in this way, the ensuing “cosmology” can be straightforwardly rejected as an exposition of how traditional, mythopoetic accounts have misled mortals in their understanding of divinity. Not only does this interpretative view provide a resolution to the A-D Paradox, it offers a more holistic account of the poem by making the opening lines of introduction integral to understanding Parmenides’ message. By setting forth its own unacceptable fiction, paralleling the elements of the Doxa in a ring-composition, the Proem simultaneously establishes the scope of the ensuing inquiry, and its target. Maintaining Parmenides’ historical position as the “father of metaphysics,” the narrative that he advanced a strictly secular account of all reality is challenged. Instead, Parmenides is best understood as further advancing Xenophanes’ criticisms of traditional religion, an intellectual relationship which the ancient testimonia strongly supports. (shrink)