Ramon Llull Session
July 21, 2011
Rooms 133-134 (CCIB)
Ramon Llull (ca. 1232 – 1316), born in Mallorca, was a philosopher and theologian who composed more than 280 books in both Catalan and Latin.
Running throughout his immense oeuvre is a leitmotif, namely the Ars lulliana or Lullian Art: a philosophico-theological system which makes use of the basic concepts from the three monotheistic religions of its day, subjecting them to discussion with a view to convincing Muslims (and Jews) via rational argument of the truth of the Christian mysteries of faith. By revising his Art and extending it to all fields of human knowledge, Ramon Llull succeeded in creating a universal science, based on algebraic notation and combinatorial figures.
Thus, for some, Llull is the founding father of computer science, especially given his influence on Gottfried Leibniz and his characteristica universalis. Llull’s contributions span over the areas of formal logic, argumentation and social choice. Recently discovered manuscripts show Llull to have anticipated by several centuries prominent work on election theory. In fact, the Borda and Condorcet voting mechanisms were proposed by him already in the 13th Century, i.e. almost 500 years earlier than the authors usually credited with developing these concepts.
This special session will assess the pioneering work of Llull in these areas. In particular, two invited talks will highlight Llull’s contributions to logic and computer science as well as voting mechanisms while a panel will broaden the discussion taking into account his influence in rhetoric, argumentation and artificial intelligence.
 Breviculum, ca. 1325
Key notes:
Prof. Dr. John N. Crossley
Monash University/Melbourne
Llull’s Contributions to Computer Science
Anachronistically, Llull (1232–1316) has been called the “first computer scientist”—a title that could apply equally well to al-Khwarizmi (who died after 846), the name commemorated in “algorithms”. Nevertheless not only did Llull contribute many ideas that have become integral parts of computer science as we know it today, some of these lie directly on the historical path that leads from al-Khwarizmi, through Athanasius Kircher to Leibniz (1646–1716) and his computing machine.
I have identified seven specific contributions by Llull, but, in addition, his general approach was to integrate ontology with logic, which is very relevant today when we are very concerned about ontologies on the World Wide Web and elsewhere.
Prof. Dr. Josep M. Colomer
Institute for Economic Analysis, CSIC
From De arte electionis to Social Choice Theory
Ramon Llull (Mallorca c.1232-1316), Doctor Illuminatus, is the founding father of voting theory and social choice theory. In two works and a book chapter he proposed and discussed a voting procedure based on pairwise comparisons of candidates by which the winner is the candidate winning the highest number of comparisons. Llull’s procedure was reinvented by the mathematician Arthur H. Copeland by the mid-20th century. The Llull-Copeland procedure produces the same winner as the celebrated Condorcet procedure, which requires winning all pairwise comparisons, when the latter exist, and is more effective in producing a winner than the Condorcet procedure in elections with five or more candidates. It is also monotonic and resistant to strategic voting. To break relatively frequent ties, Llull initially proposed lots. He later introduced a variant of the procedure based on successive eliminations and non-exhaustive pairwise comparisons which may prevent ties but is vulnerable to the order of the comparisons. Llull also discussed such important issues as the selection of candidates and secret or open voting. Some performance of Llull’s voting proposals can be assessed by examining actual uses in the medieval church and in modern sport tournaments.
Chair: Alexander Fidora (ICREA-Universitat Autònoma de Barcelona)
Salvador Barberà (Universitat Autònoma de Barcelona)
Josep M. Colomer (Institute for Economic Analysis-CSIC)
John N. Crossley (Monash University/Melbourne)
Ton Sales (UPC)