Douglas Walton (1942–2020)

We mourn the sudden passing of our friend and colleague Douglas ‘Doug’ Walton, an outstanding and highly respected member of the Argument & Computation research community.

The breadth and depth of his amazing contribution to our field (and to many others) challenge any attempt of summarization, being witnessed by a vast scientific production and by the huge impact of his ideas in shaping entire new research directions and being a source of inspiration for many further developments.

In his research and teaching, Doug emphasised that analytic tools should have relevance for reasoning and argumentation as they occur in practical, real-life situations. As a result, his writings show a diversity of methods, explored in many directions, including formal modeling, computational studies and analyses of real examples. In this way, he showed the value of a semi-formal, applied approach to logic and argumentation theory.

Doug’s work significantly supported the development of computational argumentation as a research field and community. In particular, his systematic studies on argumentation schemes and dialogues across a broad variety of applications have become a part of the shared body of knowledge in the field.

In addition to his talent and dedication in research, we will deeply miss his friendship and generosity in offering his qualities to the community. In particular, Doug served as a member of the editorial board of the journal, being a very active and careful reviewer and author, and we had the privilege of publishing several papers of him in the last years.

It so happens that his last contribution to the journal, entitled ‘Using argumentation schemes to find motives and intentions of a rational agent’, was being finalized for publication when we received the sad news of his death. It again shows his deep and wide scholarship and ambitious approach to argumentation.

It is included in the present issue as a further element of Doug’s tremendous legacy.

Pietro Baroni

Bart Verheij

Editors-in-Chief