Antonis Kakas

The general nature of reasoning is that of resolving the conflict between a formula and opposing formulae, e.g., its negation, which together will result in an inconsistency. This resolution process becomes more challenging when the premises themselves are conflicting. Nevertheless, if we accept that reasoning is about handling conflict then reasoning with inconsistency should be a natural and primary logical concept. This paper studies Argumentation Logic (AL) as a paraconsisent logic that naturally applies to logical reasoning under any set of premises, consistent or not. It presents AL as an inherently paraconsistent logical framework where the non-paraconsistent case of reasoning, i.e., reasoning with consistent premises, appears as a special limiting case of the paraconsistent logic.

This paper presents the past and present efforts of developing real-life applications of argumentation with the Gorgias preference-based structured argumentation framework of Logic Programming with Priorities. Since its free availability on the web in 2003, the Gorgias system has been used by different groups in a variety of real-life applications in areas such as medical support, network security, business computing, ambient intelligence and, recently, in the area of cognitive personal assistants. We briefly review the Gorgias framework and its past applications and present an emerging general methodological approach for developing “decision making” applications of argumentation. This approach allows the development of real world applications directly from their high-level requirements expressed in the language of the application without the need for familiarity with the underlying technical details of argumentation. A new tool, called Gorgias-B, supports this high-level development of applications and automatically generates the underlying argumentation theory in Gorgias code. The paper also reports on ongoing real-life applications in two domains: an eye-clinic assistant for first level support, and systems for patient data access and data sharing agreements according to the relevant legislation and contracts or policies of the several stakeholders involved. The proposed approach is quite general for this type of applications of argumentation and, thus, it can be used with any preference-based argumentation framework.

This paper studies the relationship between Argumentation Logic, a recently defined logic based on the study of argumentation in AI, and classical Propositional Logic. In particular, it shows that AL and PL are logically equivalent in that they have the same entailment relation from any given classically consistent theory. This equivalence follows from a correspondence between the non-acceptability of sentences in AL and Natural Deduction proofs of the complement of these sentences. The proof of this equivalence uses a restricted form of ND proofs, where hypotheses in the application of the Reductio of Absurdum inference rule are required to be “relevant” to the absurdity derived in the rule. The paper also discusses how the argumentative re-interpretation of PL could help control the application of ex-falso quodlibet in the presence of inconsistencies.

From the very beginning of their investigation of human reasoning, philosophers have identified two other forms of reasoning, besides deduction, which we now call abduction and induction. Deduction is now fairly well understood, but abduction and induction have eluded a similar level of understanding. The papers collected here address the relationship between abduction and induction and their possible integration. The approach is sometimes philosophical, sometimes that of pure logic, and some papers adopt the more task-oriented approach of AI. The book will command the attention of philosophers, logicians, AI researchers and computer scientists in general.

The book contains the proceedings of the 12th European Testis Workshop and gives an excellent overview of the state of the art in testicular research. The chapters are written by leading scientists in the field of male reproduction, who were selceted on the basis of their specific area of research. The book covers all important aspects of testicular functioning, for example, Sertoli and Leydig cell functioning, spermatogonial development and transplantation, meiosis and spermiogenesis. Even for those investigators who were not present at the workshop, this volume provides a clear impression of the topics discussed during that meeting.

Can argumentation form the basis for any form of reasoning, informal or formal logical reasoning? We examine this question from the particular perspective of the recent developments in logic-based Artificial Intelligence (AI). We propose that argumentation provides the wider framework encompassing uniformly all reasoning, with strict or formal logical reasoning being a special boundary case. We also attempt to link this unifying role of argumentation with Aristotle’s original investigation of methods and forrmalisms for the systematic study of human reasoning.

This paper studies how logic-based reasoning about actions and change (RAC) with its problems of temporal projection and qualification can be formalised in terms of argumentation. In particular, we extend earlier work of translating the language for RAC into a logic-based argumentation framework, by introducing new types of arguments for (i) backward persistence and (ii) persistence from observations. This forms a conservative extension of the language that gives a semantic meaning to domains that cannot be interpreted under thus addressing further the frame and (exogenous) qualification problems. As such the paper strengthens the link between argumentation theory and RAC in artificial intelligence.

This paper presents a way in which formal logic can be understood and reformulated in terms of argumentation that can help us unify formal and informal reasoning. Classical deductive reasoning will be expressed entirely in terms of notions and concepts from argumentation so that formal logical entailment is equivalently captured via the arguments that win between those supporting concluding formulae and arguments supporting contradictory formulae. This allows us to go beyond Classical Logic and smoothly connect it with human reasoning, thus providing a uniform argumentation-based view of both informal and formal logic.

Aristotle is generally accepted as the father of logic. The ideas that he raised in his study of logical reasoning carried the development of science over the centuries. Today, in the era of AI, this title of the fatherhood of logic has a renewed significance. Behind it lies his original idea that human reasoning could be studied as a process and that perhaps there exist universal systems of reasoning that underlay all human reasoning irrespective of the content of what we are reasoning about. In this article, we look into Aristotle’s work on human thought, his work on reasoning itself but also on how it relates to science and human endeavor more generally, from a modern perspective of Artificial Intelligence and ask if this can help enlighten our understanding of AI and Science more generally. Could Aristotle enlighten us to a new path of understanding the human capacity to think, that would allow a natural non-polluting development of AI that can energize and expand human thought into new horizons?