@book {5484, title = {Ramon Llull: From the Ars Magna to Artificial Intelligence}, year = {2011}, pages = {158}, address = {Barcelona}, abstract = {The lay philosopher and theologian Ramon Llull (1232{\textendash}1316), born in Mallorca, is undoubtedly a prominent figure within European thought. However, the exact position he occupies within the cultural horizons of his period, on the one hand, and the intellectual legacy he bequeaths to the present day, on the other, are issues often immersed in controversy. This situation derives, in part, from the protean multiplicity of his writings, manifested by an impressive variety of forms, styles and subject matter, Llull having composed some 280 works in both Catalan and Latin (as well as reputedly in Arabic). Running throughout his immense oeuvre, nevertheless, is a leitmotif that enables one to arrive at an overall, if not unitary, view, that leitmotif being the Ars lulliana or Lullian Art: a philosophico-theological system that makes use of common 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 the algebraic notation of its basic concepts and their combination by means of mechanical figures. As a matter of fact, Llull not only presented his system to the masters of the University of Paris as well as to the Pope, but he undertook several missionary trips to North Africa in order to put his Ars into practice disputing with Muslims in the market place in Bejaia and other cities. From a more abstract point of view, Llull{\textquoteright}s combinatorial Art can be described as a process of elementary analysis and of reconstruction. On the one hand, it resolves the historical religions into their most primitive elements; on the other, it represents these elements by letters (from B to K), in order to recombine these letters and the elements of the different religions that they designate until, through these combinations, a vision of the world is reached that is as consistent as possible: this will correspond to truth. Undoubtedly, this process which Llull applied to all kinds of question {\textemdash}not just religious controversies{\textemdash} is a key ingredient of modern thought. One only has to think of Gottfried Wilhelm Leibniz{\textquoteright}s characteristica universalis: thus, in his Dissertatio de arte combinatoria, in 1666, the young Leibniz, clearly inspired by Llull, had already outlined the project of a reconstruction of the whole of reality based on a definite number of basic notions. Leibniz criticizes the basic notions of the Lullian {\textquotedblleft}alphabet{\textquotedblright} as too limited and proposes another alternative and broader alphabet. In contradistinction to Llull, Leibniz does not represent these basic notions with letters but rather uses numbers. Thus, the basic notion of {\textquotedblleft}space{\textquotedblright} is represented by the number 2, the basic notion of {\textquotedblleft}between{\textquotedblright} by the number 3, and the basic notion of {\textquotedblleft}the whole{\textquotedblright} by the number 10. Consequently, according to Leibniz, a complex concept such as, for instance, {\textquotedblleft}interval{\textquotedblright} can be formulated as 2.3.10, that is, {\textquotedblleft}space between the whole{\textquotedblright}. Leibniz was convinced that in this way all questions could be reduced to mathematical problems and that, in order to solve any problem, we only have to set about calculating. This is the meaning of Leibniz{\textquoteright}s famous {\textquotedblleft}Calculemus!{\textquotedblright} It is through Leibniz that Llull{\textquoteright}s influence also became decisive for more recent developments such as formal logic, as developed by Gottlob Frege in the late 19th century. According to Frege, Leibniz{\textquoteright}s characteristica, in its later evolution, limited itself to different fields, such as arithmetic, geometry, chemistry and so on, but did not become universal as Leibniz, in fact, had wished. This is why Frege, in his famous Begriffsschrift from 1879, intended to create an elementary language that would unify the different formal languages which, after Leibniz, had been established in the different natural sciences. This language developed into the formal logic that until now has dominated the philosophical discourse and which was an important step in the journey towards the creation of computing languages. What characterizes this kind of logic is its formal notation, using variables and symbols to represent the different logical propositions and operations. Based on this notation, Frege developed the so-called logical calculus. Although the language reached by this formal logic differs from that of the Art, Llull can be considered as the forerunner of this project, insofar as in his thought one can already find the idea of an elementary language that follows logical rules and uses variables while operating with the principle of substitution of these variables.}, url = {http://www.iiia.csic.es/library/Llull.pdf}, author = {Alexander Fidora and Carles Sierra and Salvador Barber{\`a} and Mauricio Beuchot and Eduard Bonet and Anthony Bonner and Josep M. Colomer and John Crossley and Ton Sales and Guilherme Wyllie} }