21 APhEx num 21, anno 2020

Nel 1945 Friedrich Waismann introduce la nozione di open texture o porosità con riferimento alla natura dei concetti ordinari: secondo Waismann, un concetto non può mai essere introdotto in maniera tale da risultare definito "in tutte le direzioni possibili"; al contrario, le definizioni sono "sempre correggibili o modificabili". La nozione waismanniana suscita una rinnovata attenzione nel dibattito contemporaneo, in particolare in relazione alle questioni del cambiamento concettuale, della vaghezza, dell'esplicazione, dei concetti formali, e della cd. ingegneria concettuale; questo breve contributo presenta un problema aperto per la tesi che i nostri concetti, specialmente quelli logici e matematici, esibiscono open texture.

Stanisław Leśniewski (1886 –1939), Polish logician and philosopher belonging to the first generation of the Lwów-Warsaw School, contributedto the elaborationof the so-called developmentalLogics. His main research areas wereMathematical logic and Philosophy of logic. Since 1914, he elaborateda formal mereology, an extensional theory of the relations between parts and wholes that is currently the ground of many recentdevelopments in contemporary ontology and metaphysics. My aim is to present Leśniewski'slong ignored ideas and to show theircomplexity and original features throughthe critical presentation of his main works.

This paper offers a critical introduction to moral epistemology, that is, one of the emerging disciplines within metaethics and epistemology. The main sections of this contribution are devoted to addressing the three following issues: first, whether it is possible to acquire moral knowledge; second, how – viz., through which sources – we can acquire moral knowledge; and third, which implications moral epistemology draws from empirical sciences.

The main idea of distributed cognition is that a complete explanation of some cognitive phenomena should take into account non-local factors, i.e. processes that take place beyond the traditional cognitive boundaries represented by the "skin and skull" of cognitive subjects. This work outlines the developments of this viewpoint with regard to the study of linguistic phenomena. The proponents of the distributed approach highlight the active and dialogical features connected to the acquisition and use of natural language. A serious consideration of these phenomena provides the means for an original explanation of some language-related developmental issues that in computational linguistics are unsatisfactorily solved by supposing the existence of innate cognitive structures.

Megethology is the second-order theory of the part-whole relation developed by David Lewis, and it is obtained by combining plural quantification with classical extensional mereology. It can express some hypotheses about the size of the domain such as that there are inaccessibly many atoms. This will prove enough to get the orthodox set theory. Then, megethology is a possible foundation for mathematics. This paper is an introduction to megethology.