PETER OF SPAIN
(13th century)

Many medieval authors are referred to by the name of Peter of Spain. One Peter of Spain is the author of a standard textbook on logic, Tractatus (Tracts), a work that became widely known as Summule logicales (Sum of logic) by magistri Petri Hispani and that would enjoy great renown in Europe for centuries to come. This work is typical of the manuals that gradually started to emerge within the context of twelfth- and thirteenth-century teaching practices.

With regard to the identity of this Peter of Spain, matters are rather complicated. Already in the Middle Ages there existed two traditions. One ascribed the Tractatus to a member of the Dominican Order (Black Friars), the other to the Portuguese secular priest who in 1276 became pope under the name of John XXI. The latter identification was favored until the latest research, done in the late 1990s, showed that most likely the author of the Tractatus was not John XXI but a Spanish Dominican, whose identity still remains unknown.

The Tractatus are believed to have been written between 1230 and 1245. Another work that has been attributed to the same author is on syncategorematic words (Syncategoreumata ), probably written some time between 1235 and 1245. Besides these two introductory tracts on logic, there are other works written by a Peter of Spain, namely, a famous medical work titled Thesaurus pauperum and fourteen other works on medicine. A Peter of Spain also wrote Scientia libri de anima and commentaries on Aristotle's De anima, De morte et vita, and De sensu et sensato, as well as commentaries on works by Dionysius the Pseudo-Areopagite. In the manuscripts all these works are ascribed to Pope John XXI. In the late twelfth century another Peter of Spain (in modern times called Petrus Hispanus non-papa) compiled a textbook on grammar, Summa "Absoluta cuiuslibet".

The author of the tracts on logic appears to be particularly interested in matters of ontology, in dealing with which he takes a realistic approach. Every common noun signifies a universal nature and can stand for anything sharing that nature. In sentences of the form A is B, in which A and B are common nouns, the copula is signifies some composition that includes the extremes (subject and predicate) A and B, and always expresses a qualified mode of being (esse quodammodo ). Such a composition usually applies to a state of affairs possessing being in the absolute sense (esse simpliciter ), as in "Man is an animal," but if the subject refers to a fictitious entity, for example, in "A chimera is a nonbeing," being should be understood as being in a qualified sense (ens quodammodo ).

In the first example the expression man, in line with Peter's ontological stand, stands for the universal nature of manhood. Therefore, the expression is necessarily true, even if no man exists. Logical necessity, then, is based on ontological necessity, or, in other words, the necessity of propositions is founded on the necessity of the things spoken about. Necessity is associated with different types of things, like the relationships between certain concepts (such as genera and species) signifying them. Another type of necessity is found in mathematical entities. In logical argument it is important to distinguish sharply between (timeless) necessary being and being-at-a-certain-time. So an inference like "A man is necessarily an animal; therefore Socrates (who is a man) is necessarily an animal" is not valid, because a transition is made from necessary being to a being at a certain time. For Peter, the notion of necessity ultimately refers to a necessary state of affairs in reality, something that is, and must always be, the case.

Peter's account of the use of the consequential "if," in which he explains consequence in terms of causality, shows a similar connection between language and the domain of reality. Like the majority of his contemporaries, Peter has to deal with the famous question "whether from the impossible anything follows" (utrum ex impossibili sequatur quidlibet ). According to him, the notion of impossibility can be taken in two ways, namely, either (1) absolute impossibility, which amounts to being-nothing, or (2) an impossible state of affairs, the objective content, that is, of expressions containing incompatible concepts, like in "A man is an ass." Indeed, from the latter type of impossibility something (but not anything) can follow, for example, the true conclusion "Therefore a man is an animal." From absolute impossibilities, such as the one present in "You know that you are a stone," nothing can be correctly inferred, and so anything follows. To be able to make a correct inference, the antecedent should be a "something" (res ), not a "nothing."

See also Aristotelianism; Medieval Philosophy.

Bibliography

works by peter of spain

Syncategoreumata. First Critical Edition with an Introduction and Indexes by L.M. de Rijk. Translated by Joke Spruyt. Leiden, Netherlands: Brill, 1992.

Tractatus: Called afterwards Summule logicales. First Critical Edition from the Manuscripts with an Introduction by L.M. de Rijk, Assen: Van Gorcum, 1972.

works about peter of spain

d'Ors, Angel. "Petrus Hispanus O.P., Auctor Summularum." Vivarium 35 (1) (1997): 21–71.

d'Ors, Angel. "Petrus Hispanus O.P., Auctor Summularum (II): Further Documents and Problems." Vivarium 39 (2) (2001): 209–254.

d'Ors, Angel. "Petrus Hispanus O.P., Auctor Summularum (III) 'Petrus Alfonsi' or 'Petrus Ferrandi'?" Vivarium 41 (2) (2003): 249–303.

de Rijk, L. M. "On the Genuine Text of Peter of Spain's Summule logicales I. General Problems concerning Possible Interpolations in the Manuscripts." Vivarium 6 (1) (1968): 1–34.

Spruyt, Joke, trans. Peter of Spain on Composition and Negation. Nijmegen, Netherlands: Ingenium, 1989.

Spruyt, Joke. "Thirteenth-Century Discussions on Modal Terms." Vivarium 32 (2) (1994): 196–226.

Spruyt, Joke. "Thirteenth-Century Positions on the Rule 'Ex impossibili sequitur quidlibet.'" In Argumentationstheorie, edited by Klaus Jacobi, 161–193. Leiden, Netherlands: Brill, 1993.

Joke Spruyt (2005)