Raymond Llull's Contributions to Computer Science

Llull has been described, anachronistically, as the first computer scientist. Nevertheless he did make significant contributions to the discipline that is now seen as computer science. Some of these contributions are also relevant to mathematics. The latter has become well known, principally because his ideas were taken up by Leibniz (1646-1716) and his followers. We discuss these contributions. In addition we draw attention to Llull’s use of letters for entities and argue that he was the first to use the idea of substituting a value for a variable.