Logic

Logic is the study of the formal principles of reasoning. It focuses on how to attain knowledge and how to determine whether statements are true or false. Renaissance humanists* contributed to this science in two ways. First, they studied and taught the ideas of classical* writers, especially the Greek philosopher ARISTOTLE, on the subject of logic. Second, they developed new theories about the purpose of logic.

Traditional Logic. The basis of Renaissance logic was Aristotle's Organon. This important work came to the West in three stages. During the 500s the Roman scholar Boethius translated part of it into Latin, along with an introduction written by another Greek scholar. By about 1280, scholars had translated the rest of the text from Greek and Arabic into Latin. Then, in the 1490s, a new edition of the complete Organon appeared in the original Greek. Around the same time, commentaries on Aristotle's logic by scholars of the late Middle Ages also appeared in print. The recovery of these texts led to a burst of scholarship on the subject of Aristotelian logic. Jacopo Zabarella produced the most extensive works on this topic in the mid-1500s.

Aristotelian logic had a great influence on education. The lectures of the Jesuit* Ludovicus Rugerius show how important logic was to Renaissance scholars. Rugerius taught a three-year course in philosophy in Rome in the 1590s. He devoted the entire first year of this course to logic. Rugerius covered Aristotle's text in detail and also made use of commentaries by Greek, Arab, and Latin scholars, including Zabarella and other researchers of his time.

Scholars at the University of Padua in Italy played a major role in the study of Aristotelian logic. For more than a century, they analyzed and debated a section of the Organon that dealt with scientific reasoning. They focused on the problem of how to use facts to prove conclusions and achieve scientific knowledge. Zabarella provided the essential Renaissance solution to this problem in his Book on the Regress (1578).

Spanish scholars at the University of Paris pursued a different line of study in the early 1500s. They focused on mathematics and on the use of logic in philosophy and theology* rather than in science and medicine. One of these scholars, Domingo de Soto, later taught at the University of Salamanca in Spain, where he published commentaries on Aristotle's logic. His student Franciscus Toletus became a Jesuit and organized the philosophy course at the order's Collegio Romano in Rome. In 1572 Toletus published Commentaries, with Questions, on All of Aristotle's Logic. This work formed the basis of Jesuit teaching in logic until the end of the 1600s.

Humanist Logic. Some Renaissance scholars rejected traditional logic and its formal arguments as sterile and not useful. In its place they created a new logic that emphasized persuasion. They sought to link logic to grammar and rhetoric*.

One of the first scholars to pursue this program was Lorenzo VALLA, a noted Italian humanist of the 1400s. He rejected Aristotle's concern with formal proof, instead claiming that a sound argument rested on good use of language. However, few philosophers accepted Valla's new system of logic. The work of Dutch humanist Rudolf AGRICOLA was more influential. In his Three Books on Dialectical Invention (1479), Agricola proposed a form of logic based on topics rather than on terms. He argued that the formal proofs of Aristotelian logic were of limited use in debate. Instead, he advised his readers to practice the art of influencing others, to involve opponents in debates, and to aim at likelihood rather than certainty.

In the 1500s French humanist Petrus RAMUS proposed another alternative to Aristotelian logic. He divided logic into two parts: invention and arrangement. Invention meant finding the best arguments to use in addressing a particular problem or question. Ramus defined an argument as a relationship between a subject and the facts that can be stated about that subject. For example, in the sentence "Cold causes shivering," the word "causes" lays out the relationship between cold and shivering. The process of arrangement, in turn, involved laying out arguments in a useful order. Ramus proposed using outlines to organize subject matter, with headings moving from general concepts to specific ones. This technique became very popular in textbooks on all subjects through the end of the 1500s.