Peter of Spain

Peter of Spain or, in Latin, Petrus Hispanus (13th century) is the Mediaeval author of Tractatus, later known as Summulae logicales magistri Petri Hispani (Logical matters of Master Peter of Spain), a standard textbook on logic. There is a large volume of manuscripts and printed editions of that work, a strong indication that it enjoyed great success throughout European universities well into the seventeenth century. His is also often credited with a number of works on medicine.

Peter's true identity remains debated. The word Hispanus refers to Hispania, often translated as Spain, but including the whole Iberian Peninsula (as a country, Spain has existed since the late 15th century). It is often assumed he was Pedro Julião (ca. 1215-1277), the Portuguese physician known as Petrus Hispanus who in 1276 became Pope John XXI. Another theory, usually sustained by Spanish authors, asserted the author of the Tractatus was Castilian, and a member of the Dominican Order. Other theories from the fifteenth century point to Petrus Ferrandi Hispanus (d. between 1254 and 1259), or to a Blackfriar (Dominican) from the late thirteenth or early fourteenth century.

Dialectica est ars artium, scientia scientiarum, ad omnium methodorum principia viam habens; sola enim dialectica probabiliter disputat de principiis omnium aliarum scientiarum, et ideo in acquisitione omnium aliarum scientiarum dialectica debet esse prior. "Dialectic is the art of arts, science of sciences, having the way to the principles of all methods; for in fact dialectic alone credibly argues about the principles of all other sciences, and therefore in acquisition (learning) of all other sciences dialectic must be prior." — Peter of Spain.