what is a logical system 2005

the first paper under this title was published in 1994 , in a book under the
same title.
the idea is to assess the kinds of logical systems required by the landscape of
applications of logic in computer science , artificial inteligence, language,
law, common sense reasoning , etc etc
the lecture will motivate and present the author's  current view of the notion.

we will argue that a logic is not just a consequence relation, ( this notion is
now marginal) but more like a perpetual multilevel reasoning system with
mechanisms , actions, errors and  input and output points, more reminiscent of
an operating system  perpetually working and evolving.