This issue presents works from the fields of philosophical and non-classical logic.

Markin offers a universal language for constructing syllogistic theories, which greatly facilitates the proof of many important metatheorems. This is demonstrated by the example of positive syllogistics. V. Shalack exposes the similarities and differences between substantive and processual ontologies, and formulates a number of postulates that a processual ontology should satisfy. The apparatus for constructing propositional logic, in which accepted and rejected statements have the same syntactic status, is proposed by A. Citkin. The increasing interest in cognitive research requires a certain revision of our views on logic. These questions are raised by M. Urbanski. Closed classes of four-valued functions that form a seven-element lattice are presented by L. Devyatkin. N. Tomova considers a generalized algorithm for obtaining n-valued paraconsistent and paracomplete logics by combining isomorphs of classical logic. A discussion paper by G. Maksudova-Eliseeva is devoted to the eternal question of the nature and place of logic in our practice.

Published: 13.12.2020

Gleb V. Karpov

9-38

39-57

58-86

Alex Citkin

87-105

Mariusz Urbański

106-115

### On the expressive power of certain expansions of Belnap's four-valued logic

Leonid Yu. Devyatkin

116-143

### On a class of $n$-valued literal paraconsistent/paracomplete logics

Natalya E. Tomova

144-159

### Logical aliens and where to find them

Gala Maksudova-Eliseeva

160-175