Peter of Spain (thirteenth century), exact identity unknown, was theauthor of a standard textbook on logic, theTractatus(Tracts), which enjoyed a high renown in Europe for many centuries.His works on logic are typical examples of the type of manuals thatgradually started to emerge within the context of twelfth- andthirteenth-century teaching practices. Until recently he was alsoidentified as the author of a number of extant works on medicine.

• 1. Life and Works: Some Comments on the Historiography
• 2. Origins of Peter’s Works on Logic
• 3. TheTractatus
• 4. TheSyncategoreumata
• 5. Doctrinal Elements in Peter’s Logic
• Bibliography
  • Primary Sources: Works by Peter of Spain
  • Secondary Sources
• Academic Tools
• Other Internet Resources
• Related Entries

1. Life and Works: Some Comments on the Historiography

Peter of Spain has been established as the medieval author of a workthat became widely known asSummule logicales magistri PetriHispani (Collection of Logic Matters of Master Peter of Spain).The great number of manuscripts and printed editions is evidence ofthe enormous success this work met with throughout Europeanuniversities well into the seventeenth century. An interpolatedversion of hisTractatus, by then known as theSummulaelogicales, was used by John Buridan as a basic text to commentupon. But finding out the true identity of the author of thisinfluentialTractatus has proved to be a difficult task. Fora long time it was assumed that he was a Portuguese who became Pope in1276, under the name of John XXI. There is also another, earliertradition, according to which the author of theTractatus wasregarded as Spanish, and a member of the Dominican order. Yet anotherattribution, dating from the fifteenth century, was to a PetrusFerrandi Hispanus, who died between 1254 and 1259; this attributionwould be consistent with the idea that Peter’s works on logicoriginated from the first half of the thirteenth century. According tostill another attribution, theSummule was compiled by aBlack Friar no earlier than in the late thirteenth or early fourteenthcentury.

The ‘Dominican-thesis’ can be divided into threetraditions:

1. The general view that Peter of Spain, author of theTractatus, is someone who belonged to Order of BlackFriars,
2. The more specific view that the author of theTractatuswas a frater Petrus Alfonsi Hispanus O.P.,
3. Another specific view that the Peter of Spain who created theTractatus was the same Peter of Spain as the one who wrotetheLegenda sancti Dominici and the Office of theSaint’s Feast, namely Petrus Ferrandi Hispanus O.P., who died inthe 1250s.

Current research on the identity of Peter of Spain has once againtaken up the idea that he must have been a member of the DominicanOrder instead of Pope John XXI (D’Ors 1997, 2001, 2003).However, we are still in the dark about the true identity of Peter ofSpain. The most recent information we have on this score is that anumber of the Dominican candidates recently suggested as the author oftheTractatus can be deleted from the list (Tugwell 1999,2006). The lack of further information also makes it difficult toestablish the dates and specifics of his carreer.

It is still not possible to establish the date of origin of theTractatus, the work that has enjoyed such enormous success.Recent scholarship suggests that it could have been written any timebetween the 1220s and the 1250s (Ebbessen 2013, 68–69). It hasuniversally been recognised as a work by Peter of Spain. Another workthat has been identified as Peter of Spain’s is aSyncategoreumata (Treatise on Syncategorematic Words), whichwas probably written some years after theTractatus.Considering the fact that in all the thirteenth-century manuscriptstheSyncategoreumata directly follows theTractatus,and given the number of similarities between doctrinal aspects ofthese two works on logic, it is almost certain that they were writtenby the same author. Both works seem to have originated from SouthernFrance or Northern Spain, the region where we also find the earliestcommentaries on these treatises.

An extensive list of writings ascribed to an author by the name ofPetrus Hispanus is provided by Meirinhos (2018). Besides the two workson logic, the Petrus Hispanus in thepapa-tradition is thesupposed author of a famous medical workThesaurus pauperum,as well as fourteen other works on medicine. Writings by (a) Peter ofSpain in the field of natural philosophy include aScientia libride anima, and commentaries on Aristotle’sDeanima,De morte et vita,De sensu et sensato,De animalibus, and theological works include commentaries onworks by pseudo-Denys the Areopagite as well as a collection ofsermons. As yet there is no certainty about whether the author ofthese treatises also wrote theTractatus and theSyncategoreumata, or about the dates of their origin.

Another Petrus Hispanus, referred to asPetrus Hispanusnon-papa, has been identified as the author of theSumma‘Absoluta cuiuslibet’, a late twelfth-centuryhandbook on syntax closely linked with Priscian’sInstitutiones grammatice, libb. XVII and XVIII, which becamevery popular later in the Middle Ages under the namePriscianusminor (Kneepkens 1987). The chronology of this work seems to ruleout that this Peter of Spain is the same author as the author of theTractatus.

2. Origins of Peter’s Works on Logic

Peter’s logic seems to have its origin in the continentaltradition. Evidence of the educational carreer of theTractatus appears from two commentaries (see De Rijk 1968,pp. 23–34 and De Rijk (ed.) 1972, Introduction, pp. LXXff.),which contain short lemmata and a number of questions(questiones) together with their solutions. The tracts ascontained in these texts are very similar to the ones in theTractatus. TheTractatus has features that aretypical of the Paris tradition, such as the separate treatment ofampliation, restriction and distribution, as well as several otherdoctrinal elements (see De Rijk (ed.) 1972, pp.LXXXIV–LXXXVIII). We do not know whether Peter had anyconnection with Paris, nor can we say anything definitive about theidentity of his teachers. Earlier sources for Peter’s works onlogic can be traced back to Boethian-Aristotelian logic, andauthorities in the field of grammar such as Priscian and Donatus.

Like theTractatus, theSyncategoreumata alsodisplays a continental origin. It appears to have continued along thelines of a similar work by Johannes Pagus. This work, which has beendated between 1225 and 1235, was later on further developed byNicholas of Paris, who wrote hisSyncategoreumata between1240 and 1250 (see Braakhuis 1979, Vol. I, p. 248).

3. TheTractatus

TheTractatus can be divided into two main parts. One partdeals with doctrines found in the so-calledlogicaantiquorum—i.e., thelogica vetus (old logic) andlogica nova (new logic)—and the other containsdoctrines covered by thelogica modernorum—viz. thetracts that discuss theproprietates terminorum (propertiesof terms).

The first main part of theTractatus divides into fivetracts. The first tract,De introductionibus (On introductorytopics), explains the concepts used in traditionallogic—nomen (noun),verbum (verb),oratio (phrase),propositio (proposition)—andpresents the divisions of and the (logical) relationships betweenpropositions. The second tract,De predicabilibus (On thepredicables), covers matters dealt with in Boethius’s accountsof Porphyry’sIsagoge. It gives an account of theconceptpredicabile and the fivepredicables—genus,species,differentia,proprium,accidens—i.e.,the common features of and differences between the predicables, aswell as of the terms ‘predicatio’ and‘denominativum’. Tract three,Depredicamentis (On the categories), discusses the ten Aristoteliancategories, as well as some items already dealt with in the previoustreatise. The fourth tract,De sillogismis (On syllogisms),mainly goes back to Boethius’sDe syllogismiscategoricis (On categorical syllogisms). It gives an explanationof the basic element of the syllogism, i.e.,propositio, andof the syllogism, and then goes into mood and figure, the proper formsof syllogisms, and briefly deals with what are called paralogisms. Thefifth tract,De locis (On topical relationships), is derivedfrom Boethius’sDe topicis differentiis (On differenttopical relationships) I and II. This tract starts off with anexplanation of the notionsargumentum andargumentatio, and then proceeds to deal with the species ofargumentation: syllogism, induction, enthymeme, and example. Next, itgives a definition oflocus (the Latin translation of theGreektopos): alocus is the seat of an argument(i.e., thelocus is supposed to warrant the inference bybringing it under some generic rule.) The intrinsicloci (=the kinds oflocus that occurs when the argument is derivedfrom the substance of the thing involved) are covered first, followedby the extrinsicloci (= the kinds oflocus thatoccur when the argument is derived from something that is completelyseparate from the substance of the thing involved) and intermediaryloci (= the kinds oflocus that occur when theargument is taken from the things that partly share in the terms ofthe problem and partly differ from it). Examples are:intrinsic—thelocus “from definition”:‘a rational animal is running; therefore a man isrunning’; extrinsic—thelocus “fromopposites”: ‘Socrates is black; therefore he is notwhite’; intermediary—‘the just is good; thereforejustice is good’.

The second part of theTractatus comprises subjects that wereof major importance in the doctrine of the properties of terms. In thesixth tract,De suppositionibus, the theory of supposition isdealt with. The treatise begins with an exposition ofsignificatio. The definition ofsignificatio runs:significatio is the respresentation of a thing by means of aword in accordance with convention. Next it gives a definition of therelated termssuppositio andcopulatio, and thedifferences between the termssignificatio,suppositio andcopulatio. Of these threesuppositio andsignificatio are the most importantin Peter’s semantics.Suppositio is defined as theacceptance of a substantive verb for some thing.Suppositiois dependent onsignificatio, because supposition can onlyoccur via a term that already has somesignificatio. Put inother words,significatio pertains to a word by itself, andsupposition to a term as actually used in some context.

The tract concludes with a division ofsuppositio. The firstdivision is intosuppositio communis (common supposition) andsuppositio discreta (discrete supposition)—e.g., thetermshomo (man) andSortes (Socrates)respectively.

The second division,suppositio communis, is divided intonaturalis (natural) andaccidentalis (coincidental).Suppositio naturalis is described as the acceptance of acommon term for all those things that can share in the commonuniversal nature signified by the term in question—e.g.,homo (‘man’) taken by itself by its very natureis able to stand for all men, whether in the past, present or future;suppositio accidentalis is the acceptance of a common termfor those things for which the term in question requires an additionalterm—e.g., inhomo est (‘A man is’) thetermhomo stands for present men, whereas inhomofuit (‘A man has been’) and inhomo erit(‘A man will be’) it stands for past men and future menrespectively, owing to the additional termsfuit anderit.

The third division,suppositio accidentalis, is divided intosuppositio simplex (simple supposition) andsuppositiopersonalis (personal supposition).Suppositio simplex isthe acceptance of a term for the universal ‘thing’ itsignifies, as inhomo est species (‘Man is aspecies’,animal est genus (‘Animal is agenus’), in which the substantive termshomo andanimal stand for the universal man and animal, and not forany one of their particulars.Suppositio simplex can occurboth in the subject- and in the predicate-term—e.g.,homoest species (‘Man is a species’) andomnis homoest animal (‘Every man is an animal’) respectively.Suppositio personalis is the acceptance of a common term forone or more of its particulars, as inhomo currit (‘Aman is running’).

The fourth division,suppositio personalis, is subdividedinto eitherderterminata (determinate = standing for acertain particular) orconfusa (confused = standing for anyindividual falling under that name).Suppositio determinataoccurs when a common term is taken indefinitely or in combination witha particular sign—e.g.,homo currit (‘Man isrunning’) oraliquis homo currit (‘A/some man isrunning’).Suppositio confusa occurs when a common termis taken in combination with a universal sign (’Every man isrunning’).

The tract on supposition winds up with the discussion of a fewquestions regarding the attribution of supposition in a few cases.

The seventh tract of theTractatus, on fallacies, which formspart of the Aristotelian-Boethian logic, is written in the traditionof theFallacie maiores (Major fallacies). The eighth tract,De relativis (On relatives), deals with the relative pronounsas defined by Priscian in hisInstitutiones grammaticae. Therelative pronouns are devided into: relatives of substance, such asqui (who),ille (he),alius (another), andrelatives of accident, such astalis (of such a kind),qualis (of what kind),tantus (so much),quantus (how much). The former are subdivided into relativesof identity (qui andille) and relatives ofdiversity (such asalter andreliquus, both of whichcan be translated as ‘the other’). The relative ofidentity is defined in terms of supposition as what refers to andstands for the same thing. These relatives are either reciprocal ornon-reciprocal. With regard to the relatives of identity, Peter adds adicussion of a number of questions about the rationale for usingdemonstrative pronouns, and some problems concerning how the fallacyof a relative having two diverse referents comes about.

The tract on relatives continues with a brief discussion on therelatives of diversity, accompanied by a rule about the supposition ofthe relative when it is added to a superior and an inferior in apremiss and a conclusion, as inaliud ab animali;ergoaliud ab homine (‘Something other than an animal; thereforesomething other than a man’). With regard to relatives ofidentity a rule of the “ancients”, who deny that aproposition introduced by a relative can have a contradictoryopposite, is discussed and rejected. Another rule is given about theidentity of supposition of a non-reciprocal relative and what itrefers to. The tract concludes with short accounts of relatives ofaccident.

The ninth, tenth, eleventh, and twelfth tracts of theTractatus, i.e., the short tractsDe ampliationibus(On ampliation),De appellationibus (On appellation),Derestrictionibus (On restriction) andDe distributionibus(On distribution), are in fact elaborations of the theory ofsupposition. Ampliation is an extension of the supposition of a term.It occurs when an expression is combined with a modal term—e.g.homo potest esse Antichristus (‘A man can be theAntichrist’), andhomo necessario est animal (‘Aman is necessarily an animal’)—in which case thesupposition of the term ‘man’ is extended to more thanjust individuals existing in the present. The tract onappellationes is very short: appellation is considered nomore than a special case of restriction, i.e., the restrictedsupposition brought about by a present-tense verb. In this tract therules of appellation are in fact specific kinds of rules ofrestriction. The subject of restriction in general is discussed in theeleventh tract. The rules of restriction are the same ones as werepresented in the early Parisian textbooks on logic (see de Libera1982, pp. 176–177). The final tract, on distribution, deals withthe multiplication of common terms as a result of their being combinedwith universal signs. These universal signs are either distributive ofsubstance (such asomnis,nullus), or of accidents(such asqualiscumque,quantuscumque). In thisdescription ‘substance’ is defined as substistent modes ofbeing, and ‘accident’ as accidental modes of being.Separate attention is given to the universal signomnis(‘all’ or ‘every’) along with a discussion ofthe common rule that the use ofomnis requires threeappellata (particular things). The most frequently citedexample in these discussions in the thirteenth century was thesophismaomnis phenix est (‘Every phoenix is’).According to Peter of Spain, the use ofomnis does not callfor at least threeappellata; an exception to this rule isfound in cases in which there is only oneappellatum, as isthe phoenix-case. The tract also pays attention to a number oftongue-twisting sophisma-sentences.

4. TheSyncategoreumata

Peter’s treatise on syncategorematic words forms part of aseparate genre that developed from the beginning of the thirteenthcentury. The termsyncategorema comes from a famous passagein Priscian’sInstitutiones grammatice II, 15, whichintroduces two types of wordclasses (partes orationis)distinguished by logicians, viz. nouns and verbs on the one hand, andsyncategoremata, orconsignificantia, on the other.The latter are defined as words that do not have a definitive meaningon their own, but acquire one only in combination with other,categorematic words.

Like the treatises of theTractatus kind, theSyncategoreumata were developed from the (twelfth-century)theories on fallacies, as well as from grammatical doctrines (from thesame period). From the second half of the twelfth century, there was agrowing interest in the linguistic elements that are considered to lieat the basis of ambiguity and fallacious reasoning. Hence the increaseof treatises presenting a systematic account of these terms. Theconnection between these treatises and Priscian’s grammar can begathered from the attention different authors pay to thesignaquantitatis (or quantifiers) and their interest in the meaningand function of syncategorematic terms.

The list of words to be included among thesyncategoreumatawas not always the same. Generally speaking it comprised exclusivewordstantum (only),solus (alone), exceptive wordssuch aspreter (except),nisi (unless), consecutivewords such assi (if) andnisi (if not), the wordsincipit (begins) anddesinit (ceases), the modaltermsnecessario (necessarily) andcontingenter(contingently), the conjunctivesan (or),et (and),nisi (unless),in eo quod (in that), andquin (that not). In Peter’s work we also find adiscussion of the termsquanto (‘how much’ or‘as much as’)quam (‘than’ or‘as’) andquicquid (whatever). Unlike that ofsome other authors (such as William of Sherwood and Robert Bacon), hislist does not include the wordomnis.

In the opening of hisSyncategoreumata, Peter presents hisrationale for this investigation, viz. that there is a close linkbetween the use of these kinds of words in sentences and theirtruth-value. His idea is that thesyncategoreumata must havesome sort of signification, but not the same as the categorematicwords. For this special kind of signification he uses the wordsconsignificatio anddispositio.

The first two separate chapters of theSyncategoreumata aredevoted to the wordsest andnon respectively, whichare said to be implied in all other syncategorematic words.Peter’s account of the first word focuses on the notion ofcompositio (composition), which is explained in great detail,by looking into the signification of nouns and verbs (signifying acomposition of a quality with a substance, and that of an act with asubstance respectively). Considerable attention is given to thecomposition featuring in the verb ‘is’, in the form of thequestion of whether the composition involved can be counted amongbeings or not, considering the fact that it can be used to expressdifferent kinds of states of affairs. The chapter on negationintroduces the important distinction between an act as conceived of orin the manner of a concept (ut concepta sive per modumconceptus) and an act as carried out (ut exercita) (seeNuchelmans 1988). Among the former type we acts as expressed by thenoun ‘negation’ and the verb ‘to deny, whereas anact of the latter type is what is expressed by the negative particle‘not’. The remainder of this chapter deals with thefunction of the negation, which is to remove the composition found inwhatever it covers, and discusses some well-known sophisma-sentenceswhich turn on the specific function of negation.

The third chapter of theSyncategoreumata discusses theexclusive wordssolus andtantum. They are calledexclusives because they carry out an exclusion, not because theysignify one. An exclusion, furthermore, requires four things, namely,what is excluded, what is excluded from, the respect in which it isexcluded, and the act of exclusion. The kinds of exclusion are dividedinto general and specific: the former involves an exclusion fromsomething generic, whereas the latter from something specific.Questions that come up in this section have to do with the results ofadding an exclusive term to different kinds of words, such as to aterm falling under the category of Substance: does it exclude onlyother substances, or does it also exclude from things listed underanother category? And what if it is added to a term listed under thecategory of Accident (such as colour, quantity, and so on)? The nextquestion deals with the sorts of terms that can be meaningfullyassociated with an exclusion. For example, is it possible to excludesomething from ‘being’ (as in ‘Only being is,therefore nothing other than being is’)? The tract proceeds withthe kinds of things that can qualify for an exclusion. The fourthchapter, which deals with exceptive words, is compiled in a similarmanner.

The fifth chapter is about the wordsi, which is said tosignify causality in or via antecedence. The chapter also discussesthe kinds of consecution or consequence, problems of inferenceconnected with the referents of terms used in consecutive sentences,and how to contradict a conditional sentence. Special attention isgiven to the problem whether from an impossible antecedent anythingfollows.

The chapter on ‘begins’ and ‘ceases’ is a goodexample of the way in which extra-logical considerations found theirway into medieval treatises on logic. Thus, apart from the semanticsand inferential problems connected with the use of these words inpropositions, the chapter also looks into the notions of motion andtime. An important part of Peter’s ontological views can begathered from chapter seven, which covers issues connected with theuse of modal terms. Chapter eight discusses the signification and useof connectives, and the final chapter on syncategorematic words properis concerned with the expressionsquanto,quam andquicquid. A very short, concluding chapter of Peter’sSyncategoreumata deals with a somewhat isolated topic, i.e.,the proper modes of response in an argument. The topics looked intoare solution, the quantity and quality of syllogisms, and the ways togo about proving a syllogism.

5. Doctrinal Elements in Peter’s Logic

One of the most important elements in Peter’s logic concerns thedoctrine of supposition. The theory of supposition has its origins inthe twelfth century, when the medievals showed a growing interest inthe ways in which words function in different contexts. This way ofdealing with the semantics of terms has been dubbed the“contextual approach” (see de Rijk 1962–67, Vol. II,Part I, pp. 113–117).

The primary semantic property of a word is itssignificatio,in Peter’s definition, the “representation of a thing by aword in accordance with convention”. It is a natural property ofa word, the presentation of some (universal) content to the mind. Thesignificatio of a word depends on its imposition, i.e., theapplication originally given to the word in question. A word can havemore than onesignificatio, if it was originally applied totwo or more distinct (universal) natures.

The counterpart ofsignificatio, the formal constituent ofevery meaning, is the word’s capacity to “stand for”different things (even though itssignificatio remains thesame), depending on the context in which it is used. In the earlystages of the development of the theory on the properties of terms,this feature of a word was calledappellatio. For instance,the words ‘man’ and ‘horse’ can be used tostand for different individual men or horses. But they can also standfor themselves, e.g., when they are used in sentences such as‘man is a noun’, or ‘horse is a noun’.Moreover, their meaning can differ according as the words are used incombination with verbs of different tenses.

In the final stages of the development of the theory, the notion ofsupposition becomes the general label that covers all the uses of anoun (substantive or adjectival), to which other recognised propertiesof terms (appellatio,ampliatio andrestrictio) are subordinated.

The theory of properties of terms shows a radical inconsistency, whichhas been explained as “the persistent hesitation of medievallogicians between the domains of connotation (universals) anddenotation (individuals)” (De Rijk 1982, pp. 167–168).This inconsistency runs throughout Peter’s account ofsupposition, and comes to the fore most prominently in what he saysabout natural supposition (suppositio naturalis). The mainproblem is in what way the property of natural supposition is relatedto a term’ssignificatio, which was defined as theacceptance of a word for a thing (res). By this definition,thesignificatio of the term ‘man’ covers bothits intension and extension, i.e., the universal nature of man and theindividuals that have this nature in common.Suppositionaturalis, on the other hand, is described as “theacceptance of a common term for all those things that can share in acommon universal nature”; for example, the term‘man’ taken by itself by its very nature stands for allthe individuals that fall under it, whether they existed in the past,exist in the present or will exist in the future. From this definitionand the example just presented it appears that the extensionalfeatures ofsignificatio andsuppositio naturalisoverlap. The latter kind ofsuppositio has been explained byinterpreters as the natural capacity of a significative word to standfor something.

There is a more telling difference betweensignificatio andsuppositio naturalis, however.Significatio is thenatural property of any significative term to represent things, owingto its original imposition, whereas a term’s supposition onlyenters the scene when it is used. The expression “taken byitself” (per se sumptus) found in Peter’s accountofsuppositio naturalis, does not mean that no context isrequired, as is the case insignificatio, but it merelyindicates that for the moment the actual context is being disregarded.The link betweensignificatio andsuppositio is thefollowing. When some word has acquired a signification by animpositor (= someone who bestows a meaning upon a word), thenit connotes a univeral nature or essence, and acquires a naturalcapacity to stand for all the actual and possible individuals thatshare in this common nature; it owes this capacity to itssignificatio. If, however, we disregard for a moment theactual context in which the term in question is used and look upon theterm as taken by itself (per se sumptus), then itssupposition covers its entire extension. If we take the factualcontext in which the term is used into consideration, then itsextension becomes limited, owing to the context. The context, or moreprecisely, the added significative term, can be of three kinds: theadded significative term can be a predicate of a proposition in whichthe term at issue occurs, the added significative term can be anadjective, or the context can be of a social nature (see de Rijk 1971and de Rijk 1985, pp. 183–203).

The distinction betweensignificatio andsuppositionaturalis persisted throughout the thirteenth and fourteenthcenturies. Behind it is the fundamental view that regardless ofwhether a word is used in some context or not, it always has asignificatum, i.e., the universal nature or essence itsignifies, which can be separated from what the word comes to mean ina specific context.

Besidessuppositio naturalis, Peter’s (and othermedievals’) conception ofsuppositio simplex also seemsto hover between connotation and denotation. In the expressionhomo est species the termhomo hassuppositiosimplex, but this is precisely too what the termhomosignifies. So there scarcely seems reason to separate significationfrom supposition on this score. The specific use ofsuppositiosimplex found in Peter of Spain and other medieval authors, asthe representation of a universal nature, is rejected later on byauthors such as William of Ockham. For the latter, the termhomo in the example just given hassuppositiosimplex (for Ockham a special case ofsuppositiomaterialis) in that it stands for the mental concept of man(Kneale & Kneale 1978, pp. 268–269).

Peter of Spain’s logical works are commonly characterised asrevealing a moderately ‘realistic’ outlook. To explain thecontents of linguistic expressions and the function of logical terms,he is inclined to focus on their relationships to some extra-mentalreality. This can be shown from the way in which he discusses the useof the wordest (is), his account ofsuppositiosimplex, and the way he analyses the occurrence of the word‘necessarily’ in propositions. Moreover, his conception ofthe consecutive expression ‘if’ clearly shows his tendencyto put the domains of reality and language on a par. (However, not alllinguistic expressions are connected with extramental reality.Although ontology always plays a role in his accounts of language, itwould appear that Peter is especially interested in the contents oflinguistic epressions. In that regard it seems more appropriate tospeak of an intensionalist semantics.)

In hisSyncategoreumata, Peter analyses the significativefunction of the word ‘is’. To a certain extent hisfindings are not confined to that term alone, but cover all verbs, inwhich the verb ‘is’ is always understood. The mostremarkable feature about his discussion of ‘is’ is hisfocus on the notion of composition. What he is particularly interestedin is the kinds of things affirmative propositions featuring that verbcan refer to, in his words, the type of composition involved in suchpropositions.

The notion of ‘composition’ plays a prominent role inPeter’s semantics. Before embarking on the specifics of the word‘is’, he first looks into thecompositionesinvolved in the noun and the verb. When it comes to the compositioninvolved in the use of ‘is’, the starting-point for hisaccount is the question whether the expression ‘is’ in aproposition of the form ‘S is P’ implies the‘being’ of the composition. Whether it does or not dependson how we consider the composition. If we are talking about anycomposition whatsoever, in his words, the composition in general, thecomposition can indiscriminately be connected with beings andnon-beings. This is because we can talk about both things that are andthings that are not by making use of the same affirmativepropositions. Hence anything expressed by a proposition of the form‘S is P’ is a being in a certain sense (ensquodammodo). The type of composition he is referring to here isthe mental content of some affirmation, which is something that onlyhas being to a certain degree. However, the composition in general,that is, the state of affairs involved in such expressions, isprimarily connected with being rather than non-being. It is when wetalk about non-beings, such as chimaeras, that being in a certainsense once again enters the scene. Hence a distinction of the types ofbeing referred to, or the types of composition involved in affirmativepropositions into being in the absolute sense (enssimpliciter) and being in a certain sense (ensquodammodo). The difference between these two types of being isillustrated by the distinction between two types of inference: from‘A man is an animal’, in which the composition involved isa being in the absolute sense, it follows ‘Therefore a manis’, but from ‘A chimaera is a non-being’, in whichthe composition is a being in a certain sense only, it does not follow‘Therefore a chimaera is’.

The counterpart of Peter’s discussion of composition is thesection on negation. Peter specifically goes into the question of whatit is the negation denies. In his words, the negation removes thecomposition. The composition in this connection is identified with theaffirmed state of affairs (res affirmata). What the negationremoves is not the state of affairs, but the affirmation that goesalong with it. The basis of both composition and negation turns out tobe the same state of affairs, i.e., something that is formulated inthe mind, to which we can assent or which we can deny to be thecase.

The focus on matters of ontology is evidenced in other portions ofPeter’s logic as well. For Peter, as for Henry of Ghent (whoalso wrote aSyncategoreumata) the expressionhomo(man) inhomo est animal (‘Man is an animal’) hassimple supposition: it stands for the universal nature of humanity.Accordingly, the expression is necessarily true, even if no man shouldexist. The term ‘necessarily’ thus has ampliative force:it enables the subject term ‘man’ to refer to individualsnot only existing in the present ( which is the normal case when apresent-tense verb is used), but also to those of the past and thefuture. This analysis runs contrary to what is found in some otherSyncategoreumata authors, like Johannes Pagus and Nicholas ofParis, who maintain that the term ‘necessarily’ does nothave ampliative force. Hence the expressionhomo necessario estanimal (‘A man is necessarily an animal’) is onlytrue on the condition that a man exists.

A similar point is made in connection with the use of modal terms. ForPeter of Spain, logical necessity is based upon ontological necessity,or, the necessity of propositions has its foundation in the necessityof the things spoken about. Necessity is associated with differenttypes of things, such as the relationships between certain concepts(such as genera and species), and the specific things the notions ofwhich we come across in the different kinds of (scientific) knowledge(such as mathematical entities and their properties). His outlook onnecessity is clearly revealed in his analysis of the inferencehomo necessario est animal;ergo Sortes necessario estanimal (‘A man is necessarily an animal; therefore Socratesis necessarily an animal’). In his view the inference is notvalid, because a transition is made from necessary being to a being ata certain time. For Peter then, the notion of necessity ultimatelyrefers to a necessary state of affairs in reality, something that isalways the case.

A fusion of the domains of language and reality also turns up inPeter’s account of the consecutive ‘if’, which heexplains as signifying causality. Like his contemporaries he looksinto the question whether from something impossible anything follows.In his account, the notion of ‘impossibility’ can be takenin two ways, viz. impossibility as such (or absolute impossibility),which amounts to nothing, or some impossible state of affairs, that isa combination of notions that do have a real foundation but areincompatible. From the latter type of impossibility, such as ‘Aman is an ass’, something, but not anything can follow, e.g.,‘Therefore a man is an animal’. From impossibilities assuch, e.g., ‘You know that you are a stone’, nothing canfollow. The fundamental idea is that in order for something to followfrom an antecedent, the antecedent in the consecutive relationshipmust be a something (res) of some sort (see Spruyt 1993, pp.161–193).

Bibliography

Primary Sources: Works by Peter of Spain

• Petrus HispanusTractatus called afterwards Summulelogicales. First Critical Edition from the Manuscripts, with anIntroduction by L.M. de Rijk, Assen: van Gorcum & Co., 1972.
• Petrus Hispanus Syncategoreumata. First Critical Edition,with an Introduction and Indexes by L.M. de Rijk, and with an EnglishTranslation by Joke Spruyt, Leiden/Köln/New York: Brill,1992.
• Peter of Spain,Summaries of Logic. Text, Translation,Introduction, & Notes, by Brian P. Copenhaver, with Calvin Normoreand Terence Parsons, Oxford: Oxford University Press, 2014.

Secondary Sources

• Braakhuis, H.A.G., 1979,De 13de Eeuwse Tractaten overSyncategorematische Termen. Deel I: Inleidende Studie; Deel II:Uitgave van Nicolaas van Parijs’Syncategoreumata,Dissertation (Department of Philosophy), RijksuniversiteitLeiden.
• Ebbesen, Sten, 2013, “Early Supposition Theory II”,Vivarium, 51: 60–78.
• Klima, Gyula, 2011, “TwoSummulae, Two Ways ofDoing Logic: Peter of Spain’s ‘Realism’ andBuridan’s ‘Nominalism’”, in Margaret Cameronand John Marenbon (eds.),Methods and Methodologies: AristotelianLogic East and West, 500–1500, Leiden/Boston: Brill, pp.109–126.
• Kneale, William and Martha Kneale, 1978,The Development ofLogic, Oxford: Oxford University Press.
• Kneepkens, C.H., 1987,Het iudicium constructionis.Het leerstuk van de constructioin de 2de helft van de 12deeeuw. Een verkennende inleidende studie gevolgd door kritischeuitgaven van Robert van Parijs,Summa ‘Breve sit’en Robert Blund,Summa in arte grammatica en door eenwerkuitgave van Petrus Hispanus(non-papa),Summa‘Absoluta cuiuslibet’, Dissertation (Department ofPhilosophy), Rijksuniversiteit Leiden, Nijmegen: IngeniumPublishers.
• Libera, Alain de, 1982, “The Oxford and Paris Traditions inLogic,” in Norman Kretzmann, Anthony Kenny, and Jan Pinborg(eds.),The Cambridge History of Later Medieval Philosophy fromthe Rediscovery of Aristotle to the Disintegration of Scholasticism,1100–1600, Cambridge: Cambridge University Press, pp.174–87.
• –––, 1984. “LesAppellationes deJean le Page”,Archives d’histoire doctrinale etlittéraire du moyen-âge, 51: 193–255.
• Meirinhos, José, 2009, “Les manuscrits etl’attribution d’oeuvres à Petrus Hispanus”,in José Meirinhos and Olga Weijers (eds.),Florilegiummediaevale. Études offertes à Jacqueline Hamesseà l’occasion de son éméritat (Texteset Études du Moyen Âge: Volume 50), Louvain-la-Neuve:Fédération internationale des institutsd’études médiévales, pp. 349–77.
• –––, 2018, “Petrus Hispanus’Attributed Works: Searching for New Interpretations”,Enrahonar (Supplementary Issue 2018): 355-363.
• Nuchelmans, Gabriel, 1988, “The Distinctionactusexercitus/actus significatus in Medieval Semantics”, inNorman Kretzmann (ed.),Meaning and Inference in MedievalPhilosophy: Studies in memory of Jan Pinborg (Synthese HistoricalLibrary. Studies and Texts in the History of Logic and Philosophy,32), Dordrecht: D. Reidel, pp. 57–90.
• d’Ors, Angel, 1997, “Petrus Hispanus O.P., AuctorSummularum”,Vivarium, 35: 21–71.
• –––, 2001, “Petrus Hispanus O.P, AuctorSummularum, Part II: Further documents and problems”,Vivarium, 39: 209–254.
• –––, 2003, “Petrus Hispanus O.P, AuctorSummularum, Part III: ‘Petrus Alfonsi’ or ‘PetrusFerrandi’?”,Vivarium, 41: 249–303.
• Pinborg, Jan, 1972,Logik und Semantik im Mittelalter. EinÜberblick, Stuttgart-Bad Canstadt: Fromann-Holzboog.
• de Rijk, L.M., 1962–67,Logica Modernorum: AContribution to the History of Early Terminist Logic.Vol. I: Onthe Twelfth Century Theories of Fallaciesl; Vol. II: The Origin andEarly Development of the Theory of Supposition, Assen: Van Gorcum& Co.
• –––, 1968, “On the Genuine Text of Peterof Spain’sSummule logicales I: General problemsconcerning possible interpolations in the manuscripts,”Vivarium, 6: 1–34.
• –––, 1971, “The Development ofSuppositio Naturalis in Mediaeval Logic I: Naturalsupposition as non-contextual supposition,”Vivarium,9: 71–107.
• –––, 1982, “The Origins of the Theory ofthe Properties of Terms”, in Norman Kretzmann, Anthony Kenny andJan Pinborg (eds.),The Cambridge History of Later MedievalPhilosophy from the Rediscovery of Aristotle to the Disintegration ofScholasticism, 1100–1600, Cambridge: Cambridge UniversityPress, pp. 161–173.
• –––, 1985,La philosophie aumoyen-âge, Leiden/Köln/New York: Brill.
• Spruyt, Joke, 1989,Peter of Spain on Composition andNegation:Text, Translation, Commentary (ArtistariumSupplementa, 5), Nijmegen: Ingenium Publishers.
• –––, 1993 “Thirteenth-Century Positions onthe Rule ‘Ex impossibili sequiturquidlibet’”, in Klaus Jacobi (ed.),Argumentationstheorie. Scholastische Forschungen zu den logischenund semantische regeln korrekten Folgerns, Leiden/Köln/NewYork: Brill, pp. 161–193.
• –––, 1994, “Thirteenth-Century Discussionson Modal Terms”,Vivarium, 32: 196–226.
• –––, 2011, “The ‘Realism’ ofPeter of Spain”,Medioevo, 36: 89–111.
• Tugwell, Simon O.P., 1999, “Petrus Hispanus: Comments onSome Proposed Identifications”,Vivarium, 37:103–113.
• –––, 2006, “Auctor Summularum, PetrusHispanus OP Stellensis?”,Archivum FratrumPraedicatorum, 76: 103–115.

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