Informal Logic： Between Logic and Epistemology

Nowadays researchers working in various fields study the issues of argument. They represent different approaches which distinguish with theoretical and practical comprehension of argument problems. Informal study of argument is one of the approaches. The key reason of its appearance was the criticism of formal logic in the late 20th century. Researchers consider the argument from the different point of view. Formal dialectics and pragma-dialectics were based on dialectics. Contemporary rhetorical theories of argument were created on the rhetorical grounds; theory of speech acts on the basis of practical philosophy etc.. This paper is devoted to some theoretical problems of informal logic which was formed on the logic background in the late 70＇s. In spite of numerous papers, books, and text-books on informal logic published over the last thirty years, logicians has not achieved consensus so far on many issues. Among the numerous problems are： what is the subject matter of informal logic？ Does informal logic belong to the realm of logic？ Is it applied epistemology？ What is a real argument？ And what are the criteria for evaluating of such arguments？