## 1. The University of Salamanca



In order to understand the theoretical aspects of the School of
Salamanca, it is necessary to give a short introduction to the history
of the University of Salamanca. The focus will then turn mostly to two
Dominicans, Francisco de Vitoria and Domingo de Soto, and two Jesuits,
Luis de Molina and Francisco Suarez, though there were, of
course, many other extremely important participants in the various
fields of discourse in which the School engaged.



The University of Salamanca is the oldest institution of higher
education on the Iberian Peninsula. A cathedral school, located in
Salamanca by 1130, received a charter from King Alfonso IX of
Leon in 1218 as a "general school" for his realm.
The regulations for this school were promulgated by King Alfonso X
"el Sabio" in 1254. Pope Alexander IV, in 1255, confirmed
the foundation of the *studium generale* and conferred on it
the *licentia ubique docendi*, a universally valid license to
teach. Thereafter, Salamanca was recognized as a university. Courses
in theology and law were offered, with many graduates receiving
employment by the Iberian kingdoms. Lectures on authoritative texts
were the most common means of teaching. Starting in the fifteenth
century, professors also offered *relectiones*, treating in
greater depth a particular topic previously covered during lectures.
Disputations were also held. Christopher Columbus made his case for a
sea route to Asia to the university before his voyage in 1492.



Two notable learned men, Juan de Segovia and Alfonso Tostado de
Madrigal, were affiliated with the University of Salamanca in the
fifteenth century. A short account of their careers will highlight the
range of views that characterized Spanish theology at the university
in those years. Juan, a professor of theology (1422-1435),
participated in the Council of Basel (1431-1449), beginning in
1432. He defended conciliar supremacy and supported the doctrine of
Mary's Immaculate Conception. His writings include polemics on
behalf of the council against Pope Eugenius IV (1431-1447) and a
*History of the General Council of Basel*. Juan was made a
cardinal by the antipope Felix V (1439-1449); but he retired
after Felix yielded to Eugenius's successor, Nicholas V
(1447-1455). In retirement, Juan wrote on the need for dialogue
with Islam. Aware of his impending death (c. 1458), Juan bequeathed
his library to the university.



Alfonso Fernandez de Madrigal, "el Tostado", taught
theology before becoming a bishop in 1454. He, too, supported the
Council of Basel, and he displayed his knowledge in extensive writings
on Scripture and ecclesiastical history. His tract on the polity
defended popular regimes in a realm whose intellectuals usually
embraced monarchy. Alfonso also wrote against clerical concubinage.
Certain controversial opinions of his were denounced to both pope and
council. The Castilian Dominican Juan de Torquemada wrote a critique
of Alfonso's views, to which he replied. Alfonso later defended
his teachings in Rome before Pope Eugenius. "El Tostado",
on his death, left behind a reputation for great learning. (Torquemada
also set a precedent for ranking theological errors, most of them less
than heresy. The rankings given by the Spanish Scholastics set the
stage for inquisitorial inquiries into lesser errors [Vega 2022:
92]).



The Dominican order had established itself in Salamanca by 1244, when
a provincial chapter was held in that city. The convent of San
Esteban, chosen as the site of a *studium generale* of the
order in 1299, offered courses in grammar, logic and theology. During
the fourteenth century, the Dominican convent gained control of two of
the university's four chairs of theology. In 1489,
Salamanca's Dominican *studium* received from the papacy
the right to award academic degrees. The building now associated with
Vitoria and his school was begun in 1524 but not finished until 1610,
when the university was falling into decline. By that date, other
Iberian universities, especially Alcala and Coimbra, had become
competitors of Salamanca for intellectual leadership. (Alcala
excelled in the study of biblical texts [Bentley 1983].) In addition,
the Jesuits became competitors of the Dominicans as leading
philosophers and theologians. In Vitoria's century,
distinguished scholars at Salamanca included the jurist Martin
de Azpilcueta, who is known for developing a monetarist theory, and
the Scripture professor Gregorio Gallo, who considered the possibility
that the Apostle Thomas had preached in the New World. The role of the
Franciscans in the same period, including their advocacy of the
doctrine of the Immaculate Conception, requires further research (Lynn
2022; Izbicki 2022; Broggio 2002; all in Tubau ed. 2022).


## 2. Francisco de Vitoria and His Disciples



Francisco de Vitoria (1486-1546) is usually regarded as a late
Scholastic, who employed Aristotelian thought in his philosophy and
theology. Although Spanish Scholastics like Vitoria were primarily
theologians, the topics they discussed went far beyond the limits of
theology and even of the traditional philosophical companions of
theology, such as metaphysics and logic. This is partly because
Dominican theologians had to comment on the *Summa theologiae*
of Thomas Aquinas, with all the different topics it covered. The
fifteenth and sixteenth centuries saw a revival of Thomism in Paris,
Rome and Salamanca. In Rome, Thomas de Vio (Cajetan) wrote the most
influential commentary on the *Summa theologiae*. In Paris,
Peter Crockaert, a pupil of John Mair, joined the Dominican order and
became a zealous Thomist. Francisco de Vitoria, who studied in Paris,
embraced this Thomist revival. When he began teaching in Salamanca in
1524, he supplemented Peter Lombard's *Sentences* with
the *Summa theologiae* as a textbook for the study of theology.
Although the University of Salamanca was not a new foundation, Vitoria
and his disciples, especially Domingo de Soto (1494-1560) and
Melchor Cano (1509-1560), transformed it into a center for a
revived Scholasticism, applying Thomism to such practical problems as
the evangelization of the indigenous populations of the New World and
the legality of slavery. In addition, the Dominicans of Castile
influenced the intellectual development of the fledgling Jesuit order,
which produced such luminaries as Luis de Molina (1535-1600) and
Francisco Suarez (1548-1617).



Some works of these theologians can be seen as vast, overflowing
commentaries on a number of questions from the *Summa
theologiae*, especially on topics such as law and justice. Since
they were confronted by a rapidly changing universe--a so-called
New World, populated by inhabitants who belonged to none of the
traditionally known religions, and a globalizing economy (including
the slave trade)--they had to deal with new opportunities and new
problems, while still considering long-standing questions such as the
legitimacy of charging interest. Because they were understood, or
understood themselves, as confessors or as advisors of
confessors--Domingo de Soto was Emperor Charles V's
confessor, Luis de Molina declared that he wrote for the confessors of
those who hold power--they had to cope with political, economic
and legal reality, often in a quite detailed manner.



The authors of the School of Salamanca used traditional tools to deal
with the new situations they faced. Besides the overarching influence
of Thomas Aquinas--who became a Doctor of the Church in 1567 and
whose works Ignatius of Loyola had obliged the members of his newly
founded Jesuit order to study diligently--they engaged with other
medieval traditions, including the glosses to the *Decretum
Gratiani* (Gratian), Franciscan authors (especially John Duns
Scotus and William of Ockham), Jean Gerson and even Marsilius of
Padua, a banned author who was not even allowed to be cited, but
nevertheless had a considerable impact on the conciliarist debate.
Scholastic authors made a creative, instead of philologically correct,
use of their authorities, interpreting and explaining them in their
own sense. Molina and Suarez even overtly criticized Thomas
Aquinas and his understanding of law.



Vitoria's thought inevitably depended--but not
slavishly--on Thomas Aquinas, not only in his commentary on the
*Summa theologiae*, but also in his *relectiones* and
other writings on law and society. His admiration for "Divus
Thomas" had already begun when he studied and later taught
theology at Paris and Valladolid. At Paris, he had assisted in the
preparation of Crockaert's edition of the *Summa
theologiae*, published in 1515. His lectures commenting on the
*Prima* and the *Prima secundae* of the *Summa*
are lost, but must have been quite successful. His most famous works
were published after he was elected to the first chair of theology,
the most important professorship in the Spanish kingdom, at the
University of Salamanca in 1526; and, contrary to the statutes of the
university, he took the *Summa theologiae* as the basis for his
teachings (Vitoria, *Vorlesungen* 1995, 36). His reflections on
political topics, such as the political status of the Church and the
*Conquista* in Mexico and South America, were followed
attentively in the highest circles, even if not always approved, as
Emperor Charles V's harsh reaction to Vitoria's lecture
*De Indis* showed.



Vitoria's health became precarious in the 1540s, and the
dominant role at Salamanca passed to his disciples. The most important
of these was Domingo de Soto, who was born in Segovia 1494 of humble
origins, studied in Alcala and Paris, entered the Dominican
order before he was thirty and was appointed to the second chair of
theology, the *Catedra de visperas*, at the University of
Salamanca in 1532. Later he became the prior of the Convent of San
Esteban in Salamanca and was from 1548-1550 confessor to Charles
V. After this, he returned to the university, where he held the first
chair of theology. He died at San Esteban in 1560. Together with
Melchor Cano, another important disciple of Vitoria, who later became
bishop of the Canary Islands, he participated in the Council of Trent
(1545-1563) by order of Spain's privy council. Soto,
although without a vote in the council, urged bishops to attend to the
work of preaching; and he defended Scholastic theology against
proposals to suppress it. Before returning to Spain, Soto helped with
the preparations for Charles V's Augsburg Interim (1548), which
made concessions to the Protestants. One result of Soto's
presence at Trent was his tract *De natura et gratia*, which
focused on the errors of Martin Luther, whose writings he called
"diabolic" (Soto, *De iustitia et iure* VII, qu. 5
ad. 4; Grimm 2017: 64). In addition, he wrote an *Apologia*
against a fellow Dominican, Ambrosius Catharinus Politus, concerning
the certitude of grace.



Melchor Cano was less involved in controversy at Trent, concentrating
instead on issues of preaching and sacramental theology; however,
another Dominican present at the council, Bartolome Carranza
(1503-1576), the future archbishop of Toledo, participated in
the discussion of justification, arguing for "twofold
justification". Carranza was reported to be reading
Luther's works, a sign of future troubles in which his
*Commentary on the Christian Catechism* was criticized by both
Cano and Soto. Eventually, Carranza was condemned by the Inquisition
for his views on nature and grace and underwent a long imprisonment,
despite Soto's efforts to defend him with a more balanced
opinion, which Carranza cited in his own defense (Tellechea
1962-2012).



Vitoria and his disciples engaged in arguments over Spain's
rights in the New World. The debate began when the Dominicans in the
Antilles criticized the conquerors' treatment of indigenous
peoples. In a sermon given by the Dominican friar Antonio de
Montesinos on December 21, the fourth Sunday of Advent 1511, in
Hispaniola (today's Haiti and Dominican Republic), the Spaniards
who attended were told that they lived and died in mortal sin because
of the cruelties they had inflicted upon the Amerindians. One of his
listeners was Bartolome de Las Casas (1474-1566), who
joined the Dominican order and was converted by Montesinos into the
most severe critic of the *Conquista* (Las Casas, *Historia
de las Indias*).



A Junta of Burgos (1513) declared that Charles V had a sound title to
the Indies. One argument in that context, grounded in
Aristotle's thought, was that the Amerindians were slaves by
nature. This view did not remain uncontested; and, eventually, on 2
June 1537, Pope Paul III, influenced by Las Casas, issued the bull
*Sublimis Deus*, declaring the indigenous peoples to be fully
human with souls and just title to their possessions. The ongoing
debate climaxed in the disputation between Las Casas, defending the
liberty of the indigenous populations, and the humanist Aristotelian
Juan Gines de Sepulveda (1494-1573), who defended
the Spanish title to the Indies because of the Amerindian's sins
and because they were slaves by nature. This took place in the Junta
of Valladolid (1550/51), which Charles V had assembled with a number
of other leading scholars on both sides.


## 3. The Role of the Jesuits



After the deaths of Domingo de Soto and Melchor Cano, the reputation
of Salamanca's Dominicans declined. Domingo Banez
(1528-1604), a pupil of Cano, is the best known of their
successors. When his commentary on Thomas's *Summa*
appeared (1584), admitting of no dissent from its doctrines, it
provoked a controversy over the theology of grace and free will.
Banez--also the confessor of St. Theresa of
Avila--was opposed by the Jesuit Luis de Molina, who accused him
of being overly deterministic.



Molina was born in Cuenca (Spain) in 1535, entered the Jesuit order at
the age of 18, studied in Salamanca and Coimbra, taught theology in
Evora (Portugal) from 1568 to 1583 and later in Lisbon. In 1591
he was sent to the Jesuit college of his home town of Cuenca and was
elected in 1600 to the chair of moral theology at the Jesuit College
in Madrid, where he died in the same year. In 1588 Molina published a
volume entitled *Liberi arbitrii cum gratiae donis, divina
praescientia, providentia, praedestinatione et reprobatione
concordia*, usually abbreviated as *Concordia,* in which he
tried to reconcile free will with grace, God's pre-knowledge,
providence, etc. It produced a devastating effect (see below and
MacGregor 2015), a passionate debate between Dominicans and Jesuits,
raising accusations of both Pelagian and Calvinist heresy, both of
which were extremely dangerous for Catholic theologians. This
controversy continued until a congregation *De auxiliis*
meeting in Rome under Paul V decreed (1607) that Dominicans and
Jesuits could hold their own opinions on efficacious grace. The
conflict did not end, however, and in 1611 the Roman Inquisition
forbade the publication of any further books on the topic--the
most drastic case of ecclesiastical censorship of theologians in the
seventeenth century (Knebel 2000: 170).



In general, the Jesuits felt less bound than Dominicans to the
opinions of Thomas Aquinas, which meant that Molina and Suarez
were allowed a greater degree of originality in their teachings. For
this reason, some modern scholars emphasize the differences between
the Dominican School of Salamanca and the Jesuit School of Coimbra,
which came after it, though both belong to the broad tradition of
Spanish Scholasticism.



Suarez was a student at Salamanca in 1561, when he joined the
Society of Jesus. He was an educator, settling eventually in Coimbra,
where he produced a tract *De legibus ac Deo legislatore*
(1612). As a polemicist, he intervened in the quarrel over the oath of
allegiance imposed by James I on English Catholics after the Gunpowder
Plot (1605). Suarez and his Jesuit contemporary Robert
Bellarmine were the most important Catholic writers on political and
ecclesiological issues following the Council of Trent.



With the death of Suarez, the School of Salamanca and its
offshoots lost their creative edge. Instead, there was an urge to
recapitulation. The Discalced Carmelites produced an enormous
compilation of past thought, the *Cursus Theologiae Moralis*;
and the publication of its third volume in 1670 is often treated as
marking the end of the School of Salamanca.


## 4. Theology and Church Law



A common theological topic for the authors of the School of Salamanca
was the need to resist what they considered to be Lutheran heresies
(Skinner 1978: 135-173). They suspected, for instance, that
connecting legal authority to the virtue of princes could
"inveigle away the hearts of simple men from due obedience to
their princes and their priests", as Vitoria put it (*De
potestate ecclesiastica* I qu. 1, art. 2; transl. Vitoria 1991b:
55); and they regarded as heretical the view that grace is not
increased directly by the sacraments *ex opere operato* but
requires the faith of the recipient (Vitoria, *De potestate
ecclesiastica* I qu. 2, art. 2). Other points at issue were
whether all Christians could be seen as priests (ibid., II qu. 2, art.
1), the role of papacy, the veneration of the Virgin Mary and the
central problem of free will, which was denied by Luther. As we shall
see, the problem of free will and grace also gave rise to an extremely
bitter and long-lasting controversy between Dominicans and Jesuits
inside Catholicism after the Council of Trent, which had avoided the
issue except to reject Protestant theologies.



Vitoria's awareness of the challenge of Luther to Catholicism
affected his teaching and that of his successors. In his
*Relectiones de potestate ecclesiastica* (1532-1533) and
*Relectio de potestate papae et concilii* (1534), he was
critical of the Roman curia, especially on account of its free-handed
distribution of dispensations; but he was careful not to open the way
for any assault on the papacy and Catholic orthodoxy.



Vitoria's basic ecclesiology was traditional, identifying the
*ecclesia* as the "congregation of the faithful".
When heretics left this community, they did so like deserters from an
army. The Church received its power from Christ, which was distinct
from that of lay regimes, in order to promote good and resist evil.
The priesthood of the New Law superseded that of the Old Law. The
Church's power had two aspects: orders and jurisdiction. Orders
involved the sacraments, especially the eucharist and penance.
Jurisdiction included spiritual censures inflicted on erring
believers. By divine command, the Church was a "perfect"
community, that is, one which was able to defend itself and punish
iniquity.



Christ established the papacy to look after the Church's
welfare. Priests administered the sacraments under the supervision of
the pope and the bishops. Orders came via the apostles but
jurisdiction via Peter, Christ's vicar. It was the
responsibility of his successors, the popes, to build up the Church.
Bishops legislated for their diocese or province, but the pope acted
for the whole Church. Vitoria expressed great respect for general
councils as gatherings of bishops, but he maintained that a council
did not have power superior to that of the pope. Moreover, after
considering the councils of the fifteenth century, which had resolved
the Great Western Schism (1378-1417), he denied conciliarism in
its dogmatic form. The most ancient councils had not claimed that
supreme power was invested in the Church (Izbicki 2019).



Spiritual power was superior to temporal, but that did not make the
pope lord of the world. Papal power could have an impact on Christian
regimes, making and unmaking rulers, but only for spiritual ends. The
pontiff could authorize just wars against the Saracens and other
enemies of the faith. The ecclesiastical commonwealth had its powers
from grace, but grace did not cancel nature. To the contrary:
According to Aquinas "grace presupposes nature and perfects
it" (*Gratia praesupponit naturam et perficit eam*, ST I
qu. I art. 8 ad 2).



The topic of grace and free will was the main ingredient of the
controversy over Molinism. It began with the work of Molina mentioned
above, *Liberi arbitrii cum gratiae donis, divina praescientia,
providentia, praedestinatione et reprobatione concordia* (Molina
*Concordia*). In it he explains how God can preserve his
omnipotence, providence and pre-knowledge, while conceding free will
to humans, by means of his *scientia media*, or "middle
knowledge", which gives him the ability to know what human
beings will decide--but no control over their decisions.
*Scientia media* is placed between *scientia naturalis*,
by which God knows everything that can be, and *scientia
libera*, by which he knows what will be. Molina places God's
counterfactual knowledge before the creation--contrary to Luther
and Calvin. God's omnipotence consists in the possibility that
he could have created beings without the capacity to accept or reject
the offer of grace by their will (*Concordia* pars IV, disp.
52). Furthermore, humans are able by their free will, without the
special help of God (*sine auxilio speciali Dei*;
*Concordia* pars I, disp. 5 [1953: 29]), but only with his
*concursus generale*, to act morally in a temporal sense.
However, they need grace within temporal life and God's special
help for the effort to receive eternal grace, i.e., the *visio
beatifica,* the vision of God of the blessed after their death. In
the ensuing controversy, known as *De auxiliis*, fierce
criticisms came from the Dominican Domingo Banez, who had the
first chair of theology at Salamanca, and his pupils; they held a
special Thomist theory of grace, which referred to the
*praedeterminatio physica*, mankind's inability to resist
God's grace.



It is easy to forget that Suarez was concerned not only with
metaphysics and law; but he has also been described as the founder of
Mariology on account of his treatment of the Immaculate Conception and
Mary's bodily assumption. Suarez took a balanced view of
the issues of divine foreknowledge, free will and predestination in
the *De auxiliis* controversy; and, building on Molina, he
developed the doctrine of Congruism, which argued that God had
arranged matters to allow free will to assent to grace. He also
discussed how God rewards the good and punishes sinners.



Suarez was a confirmed papalist, who regarded the Holy See as
necessary to the Church's unity. Canon law existed as a distinct
aspect of human law, supporting humanity's higher ends and
unifying all peoples. The pope was divinely guided in pronouncements
on doctrine, and he had a universal responsibility to spread the
gospel. Suarez, however, refused to accept evangelization as an
excuse for war. Not even unnatural acts justified the use of violence.
Consequently, Suarez, like Vitoria and Soto, upheld the
legitimacy of non-Christian regimes operating within the bounds of
natural law.


## 5. Natural Law, Political Theory and the Rise of International Law


### 5.1 Natural Law



One of the generally acknowledged merits of the School of Salamanca
was the revival of natural law or at least its Thomist version. This
was more or less closely connected to commentaries on the second part
of Thomas Aquinas's *Summa theologiae*. Vitoria's
lectures on the *quaestiones* 90-105 of the *Prima
secundae*, entitled *De lege*, dealing with the different
kinds of law, and his voluminous commentary on the *Secunda
secundae* are now available in critical editions by Vicente
Beltran de Heredia. Molina described his monumental *De
iustitia et iure*, which in current forms of printing would take
up around 6,000 pages, as a commentary on *quaestiones*
57-79 in the *Secunda secundae*, but he admitted that he
was not following Thomas precisely and that his theory covered a wider
range compared to what had been discussed by "Divus
Thomas". Whether the ten volumes of Suarez's *De
legibus ac Deo legislatore* are primarily to be seen as a
commentary on *quaestiones* 90-108 of the *Prima
secundae* is still debated by modern scholars. Soto, who is
mentioned by Suarez as one of his main sources besides Thomas
Aquinas, commented on questions from both the *Prima secundae*
and *Secunda secundae* in the ten books of his extremely
influential treatise *De iustitia et iure.* The common
background for all the authors of the School of Salamanca, as well as
their Jesuit successors, who dealt with law, natural law and justice
was, therefore, Thomas Aquinas's division of the different kinds
of law in the *Prima secundae* and his reflections on the
different meanings of justice, law and right from the *Secunda
secundae*, whether they followed him or not.



The classification of laws in the *Summa* (Ia IIae, qu.
91-4) begins with God's regulation of the universe via the
eternal law, manifest to humans through revealed divine law and
through natural law, which was accessible by reason. Humans, even
those lacking revelation, could derive from natural law the principles
for enacting human law. Human law, inevitably, had to be adapted to
time, place and climate and was, therefore, limited. Nor was reason
able to craft laws covering all contingencies. They had to be useful
to the commonwealth and also mutable if circumstances changed.
Dispensations were required where a law did not apply in a particular
case. Disobeying laws was a vice, while obeying them was a virtue.
Divine law, embodied in the Old Law or the New Law, which regulated
contingent elements of religious cult, but also the punishment of
those who had escaped human justice, was in accordance with natural
law and eternal law. Human laws were invalid if they contradicted
either divine or natural law. In the *quaestiones* 57-79
of the *Secunda secundae,* Thomas addressed questions such as
"Whether right is the object of justice", and "What
is justice?"; he also discussed judgment, kinds of justice,
restitution, injustice, kinds of injustice and so on.



Vitoria followed this schema in his lectures on the *Summa
theologiae*, especially in his 1533-1534 lectures and in his
commentary. He treated law as made by "reason and
enlightenment", not just the will. Natural law, derived from
eternal law by reason, was binding on all humanity; its principles
applied to mutable situations and different peoples. God was the
indirect cause of human laws, which were binding on the consciences of
individuals. There was a human urge to obey natural law, for example,
by honoring one's parents, preferably out of love. Failure to
heed these precepts was a moral fault.



The gospel was valid when promulgated by Christ, but barbarians
ignorant of the gospel might violate its commands in a pardonable way.
The Church had general laws which were applicable anywhere, and
failure to obey them was sinful. Human legislators could enact laws
favoring religion, but they must not confuse their role with that of
the clergy under divine law.



Human laws were intended to serve the common good, not the interests
of the legislator, who was "the servant of the
commonwealth". Any "perfect" community, sacred or
secular, had the power to make and enforce laws. Human laws were
binding once publicly promulgated; but the Church had its laws from
God. The Church had one ruler on earth, the pope, the vicar of Christ,
just as the universe was ruled by God; but, like other rulers, the
Roman pontiff delegated power for its effective exercise.



Despite the preeminent place that Thomas Aquinas occupied for these
authors, there are significant deviations from the Thomist concept of
natural law that are shared by some of them, who at times also
directly criticized the "Doctor Angelicus". Suarez,
for instance, says that law has to be seen as something that rules the
behavior of beings capable of free decisions (*De legibus* I
iii 2); therefore, Thomas's concept of an eternal law that rules
the whole universe can be understood as a law only in a metaphorical
sense. There are still ongoing debates as to whether eternal law can
be seen as the theological basis of all other kinds of law
(Schweighofer 2018: 234-256). Natural law, for Thomas, on
the one hand, is known to humans because of their participation as
rational beings in eternal law, but, on the other, it is at least
partially shared with animals (*Summa theologiae* Ia IIae qu.
95 art. 4 ad 1; IIa IIae *quaestio* 57 art. 3 co) in parallel
to Roman Law (Digest 1.1.1.4). Its role for Thomas was labeled as
something like a "style", i.e., a universal principle
(Westerman 1998: 81) governing animate nature. For Suarez it
becomes a device to rule the behavior of humans as rational beings who
are responsible for their activities. It not only contains the most
general principles of law, leaving the more detailed regulations to
human law, but also everything that follows logically from these
principles; otherwise not even the ten commandments would belong to
natural law. According to Suarez, natural law is the voice of
right reason which effects human behavior via man's conscience,
and 



> 
> 
> a man who is led by this law is said to be his own law, because he has
> the law written within himself
>   
> 
> *dicitur homo, qui illo ducitur, sibi lex, quia habet in se
> scriptam legem*. (*De legibus* II v 9-10) 
> 
> 
> 



This conceptual shift was initiated at least implicitly by Vitoria in
his commentary on *quaestio* 57. Thomas gives as an example of
what is just by nature in an absolute sense the natural inclination of
the male to the female for the sake of procreation and the efforts of
parents to nurture their children. Vitoria replaces these examples by
the obligation to return deposits and the Golden Rule. This
moralization of natural law is not found in all the authors under
consideration. Molina, for example, argues that someone who uses the
extreme poverty of another to make that person his slave, instead of
providing help without imposing conditions, commits a sin against
charity; but the contract is valid according to natural law (*De
iustitia et iure* II, disp. 34).



The Salamancan theologians and their successors not only discussed and
modified Thomist natural law but also referred to other sources with
slightly different categorizations, such as the distinction between
*ius humanum* and *ius naturale vel divinum* made by
Isidore of Seville (*Liber etymologiarum*, lib. 5 c.
2-18), cited in *Decretum Gratiani* (Gratian [1879: vol.
1, 1-5]) and discussed by Soto (*De iustitia et iure* I,
qu. V, art. iii and iv). There were many further differences among
them on natural law, as on law in general. For instance, with regard
to whether law was an act of will or an act of intellect, some, like
Soto, favored the intellect despite his early education in
Nominalist-dominated Paris, where voluntarism, an emphasis on the will
over the intellect, prevailed; others, like Suarez, gave some
relevance to the will. Nevertheless, they were in agreement that the
principles of natural law were inscribed in the hearts of humans, so
that "no human being can plead ignorance as an excuse", as
Soto put it (*De iustitia et iure*, I qu. I art. iv; transl.
Hamilton 1963: 15). Suarez's concept of law has been
described as voluntarist, but reason still played a significant role
in his thought. Reason diagnosed situations, identifying possible
remedies; but the will implemented these measures. These deliberations
happened within the context of immutable natural law, which
Suarez believed was known through specific precepts. In
addition, he held that individual virtue lay in following right
reason. Reason's dictates were unique to human beings, not
impulses shared with animals. The laws common to many peoples, though
not universal, made up the *ius gentium*. What may seem at
first glance an acknowledgement of the moral competence of all human
beings was also used to justify punishment, including war and
enslavement, against peoples from other continents.



It is the *ius gentium*, not natural law, that regulates the
distribution of property and the enslavement of human beings. The
immutable natural law, however, gives permission for these activities,
because, after the Fall, the circumstances of its application changed
dramatically, making an enforced regulation of possession necessary
(see, e.g., Suarez, *De legibus* L I xvi 7). Although
property--or *dominium* as it was called--is not part
of human nature, according to the majority of Salamancan thinkers and
their followers, there are many reflections by different authors
arguing for the advantages of private property. Soto and Molina make
direct use of Aristotelian and Thomist arguments, saying that common
ownership would prevent men from working and from taking care of their
things to the disadvantage of the common good (Soto, *De iustitia
et iure*, IV art. 3; Molina, *De iustitia et iure*, II 19;
see Chafuen 2003: 3-38). There are differences concerning the
way in which *dominium* in this sense is bound by regulations
from positive and natural law. Most authors, such as Vitoria, in his
commentary on *quaestio* 66 in the *Secunda secundae* of
the *Summa theologiae*, accepted the Thomist view that those in
extreme need are entitled to take what is necessary for their
survival. Martin de Azpilcueta (1491-1586), known as
"Doctor Navarrus" or "Navarro", however, held
that there is no obligation to donate to those who are in extreme need
and that anyone who receives such a donation must see it as a loan,
not as something of his own (Chafuen 2003: 44).



Some of these theologians adopted an understanding of the word
*ius* in the sense of right, even subjective right. This is not
a Salamancan invention but seems to have been initiated in the glosses
to the *Decretum Gratiani* and enforced by authors like Ockham
and Gerson (Tierney 1997). But it plays an important role in arguments
on *dominium*--a term that oscillates between domination
and property--and in reflections on the *ius gentium*. The
first lecture of Vitoria's *De Indis* deals with the
question of whether the Indians may be called *veri domini*,
that is, real masters or real possessors, of their goods, and the
third lecture claims that they violated the rights of the Spaniards.
Molina takes this subjective meaning of *ius* as the
paradigmatic understanding of the term throughout his voluminous
treatise *De iustitia et iure*. He defines *ius* as 



> 
> 
> a faculty to do or have something or to maintain it or to behave in
> any way such that if it is hindered without legitimate reason an
> injury is done to the person who has it. This way, that right, in this
> meaning, becomes something like a measure of injury: because as much
> as it is opposed and damaged without legitimate reason, injury is done
> to the one who has it. (*De iustitia et iure* II 1) 
> 
> 
> 



Though it may be exaggerated to call the School of Salamanca the
cradle of human rights, individual rights are pivotal for a number of
their arguments. Molina states that a slave may have a *ius qua
homo*, even in the special case of a right to things he has won
from his master in gambling and suchlike. Furthermore, he declares
that an injustice toward someone is a violation of that person's
rights, and he gives a number of examples where injustice is done
toward a slave and must be corrected or punished. We may, therefore,
conclude that slaves also have rights in his system (*De iustitia
et iure* II 38).



The issue of slavery in the New World cannot be divorced from racial
concerns. African slaves were imported. Also, Spaniards and indigenous
peoples intermarried with each other and with black slaves.
Classifications were developed to designate various mixtures. It is
notable that these mixed populations received marital privileges the
papacy issued for converts in the New World. However, ideas of infamy
arose, describing mixed populations with language indicating
inferiority. Also, this language indicated levels of mixture with
indigenous populations by proportions as small as one sixteenth. (R.
Hill 2022: 585-611). The discrimination of Africans as a
"justification" of enslavement began even before the
"discovery" of America, using, among others, the biblical
reference to Noah's curse Genesis 9:20-27. However, the
concept of race in the modern sense was developed from eighteenth
century onwards, while earlier writers used the term
"nations" to speak about Africans and Amerindigenous
peoples who were allegedly "like beasts" and determined to
serve (Haar & Kaufmann 2023: Kap. 4 and below).


### 5.2 Political Theory



The central topics in the political theory of authors from the School
of Salamanca are the aim of political community, the legitimacy of its
power and the relationship between the commonwealth and its ruler.



In his lecture *On Civil Power* (*De potestate civili*),
Vitoria holds that every power, public or private, comes from God and
cannot be abolished by human beings, not even if they are in full
consensus. Vitoria's ideas about society depended partly on his
Aristotelian belief that human beings are social by nature, needing
others to survive and achieve a good life. Thus, a natural good,
survival, not moral goodness, was its original purpose. Nature,
following God's purpose, had implanted in early peoples the urge
to establish households, cities and regimes. Society eventually came
to promote virtues, especially justice and amity, which supported the
common good. He followed in a certain sense an Aristotelian line,
using the theory of the four causes for his analysis, first of public,
then of private power, and starting with the final cause, which was
regarded in the Aristotelian and Thomist tradition as the necessary
cause. According to Vitoria, 



> 
> 
> the origin of human cities and commonwealths was not a human invention
> ... but a device implanted by nature in man for his own survival
> 
> 
> 
> 



and for the sake of this it also needs an "ordering force"
(ibid., qu. 1, art. 2, p. 9). The efficient cause of public power is
God, and its material cause is the commonwealth itself. Royal power is
not from the commonwealth, even if the king is elected, but from God
himself (ibid., qu. 1 art. 5). Non-Christians have legitimate rulers,
and a legitimately constituted power cannot be abolished by the
consent of the people (ibid., qu.1. art 6-7).



All peoples created regimes: since a multitude could not govern itself
well, power was entrusted to a group or individual acting for the
common good. The best regime, in Vitoria's opinion, was rule by
one person, who was both above the community and within it.
Individuals might even sacrifice their lives in defense of the common
good. Society's natural purpose, the preservation of temporal
life of its members, was not in contradiction of the Church's
end: the salvation of souls. In a Christian commonwealth, salvation
was the primary purpose, with human felicity as the secondary end. The
commonwealth transferred its power to the ruler, but his power
ultimately derived from God; and after its transfer of power to the
ruler, the commonwealth ceased to be able to legislate. Since the
ruler was within the commonwealth, he was bound by its laws. Vitoria
states that monarchy is the best form of government, but insists that
a commonwealth may be punished for the sins of its king, if he, for
example, wages an unjust war against another prince (ibid., qu. 1 art.
8-9). This commonplace among the theorists of the *ius
gentium* was important for some of the justifications of slavery
and the slave trade, because captives in a just war traditionally
became slaves and because the punishment of a commonwealth decided the
fate of all its members, regardless of their individual guilt or
innocence. 



Once different temporal regimes were created, each ruler was situated
within a commonwealth. The ruler of France could not legislate for
Spain. A ruler with multiple realms, like Emperor Charles V, had to
promulgate laws in each region. Within a realm, custom was supposed to
reinforce law or to be enforced itself. A ruler was best advised to
support good customs. Vitoria faced the possibility that some laws
might be obeyed only by a few citizens, in which case they could be
revoked by the ruler. Revoking laws arbitrarily, however, might be
sinful. Even a tyrant's laws had to be obeyed if they served the
common good. Vitoria claimed that legislators are bound by civil laws
(ibid., qu. 3 art. 4), but that the laws of tyrant are valid (ibid.,
qu. 3 art. 6), a view which conflicts with positions later held by
Jesuits. The community, according to Vitoria, retained the right to
defend itself against a tyrant threatening its survival, but it could
not abolish a licit regime. The regime did not have to be Christian,
but a non-Christian regime could not be overthrown solely on the
grounds of injustice.



Soto never denied that God is the ultimate origin of the Christian
commonwealth, but he distinguished between the natural and
supernatural order and held that, in the natural, temporal order,
peace and tranquility have to be guaranteed by the commonwealth and
can be identified with the *bonum commune* (Grimm 2017:
74-77; Soto, *De iustitia et iure* I qu. I art. ii). This
internal peace, the *bonum commune*, is the aim of any
legitimate law; on the other hand, it is stabilized by just laws,
which are more easily followed in a peaceful society. In this way, the
theologians of the School of Salamanca implicitly paved the way for a
secular understanding of the state as a human institution that
preserves peace and prosperity within a society. There are differences
between some of the authors concerning the anthropological question of
whether human organizations and the distribution of property were
already to be found *in statu innocentiae* or only later, after
the Fall, when domination and property became necessary because of
human weakness. 



Molina explained why and how domination was introduced after the Fall,
coining the term *dominium iurisdictionis* for temporal power,
in contrast to *dominium proprietatis* (*De iustitia et
iure* II 20, II 22, II 23; Brett 2014), in order to avoid the
equivocal use of the term *dominium* that had confused
discussions since the debate on Franciscan poverty in thirteenth and
fourteenth centuries (Brett 1997). The political authority of the
commonwealth--*res publica*--is directly given by
God, as it was difficult to imagine that there was a new contract in
every generation. Nevertheless, the power (*potestas*) of the
government comes only indirectly from God and directly from the
republic (*De iustitia et iure* II 26.4). Molina accepted the
common Salamancan view that communities had transferred power to
rulers.



All dominion was founded on natural reason, shared even by
non-Christians. "Government is the channel through which the
natural power of the commonwealth is exercised" (Costello 1983:
49). Therefore, if a government misuses its power by trying to
exercise a *dominium proprietatis* over its citizen, that is,
treating them like slaves, there is a right to resist. This also holds
for a king, notwithstanding that, for Molina, monarchy was the best
form of government (*De iustitia et iure* II 23.10). While this
resistance has to be supported by the common will of the citizens in
the case of abuse of power by a legitimate ruler, every citizen has
the right to kill an illegitimate usurper of power (ibid., III
6.2).



Suarez believed that individual peoples reached agreement on
the need for government. God then granted rulers power to direct
humanity toward its proper ends. Critics of his thought, like Robert
Filmer, objected to bringing in God at this late stage, in order to
explain the formation of regimes, rather than emphasizing his role in
the creation of commonwealths since Adam (Filmer 1680, chap. II [2]).
Suarez thought that it was the responsibility of the ruler to
promote harmony between subjects, to exercise power well and to enact
laws to perfect the community. He also treated the relationship of law
to conscience and that of ecclesiastical to lay powers. Like many
representatives of Spanish Scholasticism, Suarez favored
monarchy, within limits, as the best regime. Individuals had the right
to self-defense, as did the society as a whole, and they might resist
a ruler who acted badly. Suarez even contemplated the
possibility that tyrants could be killed for threatening the survival
of the commonwealth. In his polemics against King James I of England,
he argued for the immunity of the Church from control by lay regimes.
The English oath, the so-called oath of allegiance that King James had
required his subjects to take in 1606, the year after the Gunpowder
Plot, he said, violated this immunity and undermined obedience to the
Roman pontiff in spiritual matters. Suarez was willing to
believe that the pope could exhort the people to rise up against a
tyrant or to invoke the aid of outsiders against one. Except in such
cases, however, Christians were to obey their lay rulers in conformity
with natural law. This right to resistance was widely taken for
granted by the Jesuits and considerably expanded by Juan de Mariana
(1536-1624). Although recent scholarship has cast doubt on the
traditional labeling of Mariana as an exponent of popular sovereignty
and tyrannicide (Braun 2007), the Catholic zealot who assassinated
Henry IV of France in 1610 is known to have referred to his
writings.


### 5.3 Ethics and Casuistry



Spanish Scholasticism reflects a long-standing tradition of teleology,
which looked to the final cause of human conduct. Humans bore the
image of God, including the rationality Suarez saw in all
mortals. These beings could be moved by reason to right conduct,
individually and in politics. (Pink 2022: 279-305). Spanish
Scholastics like Bartolome de Medina and Azpilcueta were deeply
concerned with casuistry, the means of guiding human conduct. Others,
including some Protestants, used similar approaches. Casuistry can be
found in the discussion of such issues as lying through "mental
reservation". Cases of conscience were compiled to help in the
guidance of souls, especially in avoidance of sin.



The uncertainties of life led to the development of the idea of
"probabilism," looking to what was most likely when
certainty could not be obtained. Medina was a pioneer in this,
claiming that, when in doubt, one might discern the more probable
opinion. This, in turn, permitted choosing the "more probable
option"--or even a less probable choice--in moral
decision making. It looks as if the first traces can already be found
in writings of Vitoria and Alonso de la Vera Cruz (Egio
Garcia 2022). Probabilism was also used by some of the Jesuits
who were active in South America and Nueva Espana when they had
to cope with problems of the treatment of Indigenous peoples and with
African slavery, e.g., Diego de Avendano (1594-1688)
(Avendano 1668; Haar & Kaufmann 2023: Kap. 2.4.2.,
4.2.).



More strictly, some theologians said to adopt only the safest course
of action. Critics of such approaches, including Blaise Pascal,
denounced them for laxity, leading to use of "casuistry"
as a negative term (Schussler 2022). 


## 6. *Ius gentium, ius ad bellum* and the Enslavement of Amerindians, Africans, and Others



Among the most influential elements in the works from the School of
Salamanca are those connected to what was called the *ius
gentium* until the late eighteenth century but is nowadays
referred to as international law. Firstly, they separated the *ius
gentium* from natural law, with which it had more or less been
identified with since the formulation of Roman Law; secondly, they
developed a martial law on the basis of *quaestio* 40 in the
*Secunda secundae* of Thomas Aquinas's *Summa
theologiae*; and thirdly, they treated the alleged right to
enslave non-European human beings.



When James Brown Scott (1934: 3, 160) called Vitoria the father of
modern international law, it was mainly in reference to his lectures
on the problems associated with the Indies. Vitoria's opinions
on this matter loomed large in this debate. He addressed the Indies in
three *relectiones*: *De temperantia* (1537), *De
Indis* (1539) and *De iure belli* (1539). In the first of
these he discussed cannibalism, while in the others he considered
whether a just war could be waged against indigenous peoples and
whether Spain's title to the Indies was valid. In addition,
Vitoria, lecturing on the *Summa theologiae* (1534), discussed
evangelization. His account of the right to rule also extended to the
role of the clergy in evangelizing peoples who, before 1492, had never
heard of Christ.



As mentioned above, in the first of his three lectures *De
Indis*, delivered in the summer of 1539, he shows that the
Amerindians were *veri domini* of their goods, even if they
were unbelievers, sinners and irrational (Vitoria 1991b:
239-250). He discussed the argument from Aristotle that
"barbarians" were little better than animals, madmen or
those lacking sense, then he turned to an argument of apologists for
the *Conquista*, claiming that Amerindians were infidels,
living in a perpetual state of mortal sin, requiring Christian
intervention. He dismissed the argument from sin, on the grounds that
sin did not cancel natural *dominium*. Brute beasts lacked such
rights, but even children and the mad, although they had guardians,
nevertheless had property rights. Aristotle wrote about those who
needed direction from others, but this did not negate ownership.
Vitoria extended rightful ownership even to Saracens. He blamed the
poor education of indigenous peoples, which he compared to that of
many European peasants, for their depraved condition. Slavery, he
added, was a legal or civil construct. No one was a slave by
nature.



The second lecture lists seven "unjust titles" for the war
against the Amerindians. Vitoria rejected the idea that either the
emperor or the pope is master of the world. He denied that Emperor
Charles V could take away the domains of others. He cited Juan de
Torquemada's *Summa de ecclesia* to prove that the
pope's supremacy was spiritual, not temporal; and he maintained
that the pope could not force unbelievers to convert. According to
Vitoria, discovery was not a justification for conquest; and he
refuted the view that sins against nature like cannibalism and incest,
which were exceptions to the natural immunity that canon law allowed
to non-believers, justified conquest. There were sinners in every
nation, but the pope was not entitled to wage war against Christians
who were guilty of sin. Furthermore, neither the alleged voluntary
choice of the Amerindians nor the idea of a gift from God could
justify the conquest of their territory (ibid., 252-276).



The third lecture, finally, lists eight "just titles" for
the war against Amerindians, among them the violation of the right of
Spaniards to travel in the Indies and to conduct missions, the
protection of innocents, etc. (ibid., 278-291). Vitoria argued
for free intercourse between all peoples: indigenous rulers could not
exclude Christians from their lands, and Christian travelers attacked
by the local inhabitants had the right of self-defense. Spanish
children born in the New World were able to choose, under natural law
and the *ius gentium*, to become citizens of the country where
they resided. Vitoria also argued for the right to evangelize.
Christians could intervene to protect converts, allies and friends. He
warned, however, that waging war on indigenous peoples might obstruct
conversion. Vitoria weakened his defense of the Indians by saying that
Spain might govern them for their own benefit. The indigenous peoples
might even be treated "partly as slaves". Moreover, once
large-scale conversions had taken place, Spain could not abandon the
New World.



In *De temperantia* Vitoria stated that all nations regarded
cannibalism as an abomination. A prince might convert and suppress
evil customs like human sacrifice on the grounds of justice; but
foreign princes could not intervene. Vitoria also dismissed arguments
from sins against nature as calumnies intended to excuse warfare and
plunder.



Vitoria and the other authors of the School of Salamanca dealt with
martial law and developed a theory of just wars that was, on the one
hand, based on Thomas Aquinas's arguments and, on the other
hand, built on the foundation of the "classical doctrine of just
war" (Orend 2006). Vitoria dealt with just war in his lecture
*De Indis relectio posterior sive De iure belli.* He discusses
who can wage war--private persons only for self-defense, the
commonwealth and the prince also for other reasons (Vitoria 1991b,
299-302); what cannot be considered just reasons for waging war,
such as difference in religion and enlargement of empire (ibid.,
302-304); what can be done in a just war (ibid., 304-306,
314-317); and the view that it may not be enough if a prince
believes that his war is just (ibid., 306-307).



Vitoria regarded a "perfect" commonwealths as able to
defend themselves from internal and external threats. The right of
self-defense permitted the use of force to repel force. A society,
pagan or Christian, could wage a just war in self-defense and execute
malefactors. Vitoria accepted repelling invaders and avenging injury
as justifications for war, but not the invasion of realms in order to
acquire land, slaves or plunder. Religious difference and the
vainglory of princes were also not sufficient reasons. Those in
authority could declare and wage war, but they should take counsel
about this. Subjects could not refuse service in a just war. All
necessary means were acceptable in a just conflict, even entering an
enemy's territory. Vitoria, however, applied a criterion of
proportional harm to wars, so that a war was unjust if it caused more
harm than good. Moreover, a ruler who had waged an unjust war was
obliged to make restitution. Booty could recompense property unjustly
seized by an enemy, but only if taken on a superior's orders.
Vitoria permitted enslaving Saracens defeated in a just conflict, but
he denied that Christians could enslave other Christians. Moreover, he
denounced devices used in capturing slaves for export. Overall,
Christians were expected to abide by the rules of war, showing
moderation and humility when victorious.



Similar ideas--legitimate authority; just cause, which only one
side can have; trying all other ways of conflict resolution;
etc.--can be found in Suarez's *De bello*,
the thirteenth disputation of his *De caritate*. Molina,
however, seems to have believed that, at least from a subjective point
of view, both sides may believe that their cause is just (Fernandes
2014).



According to Molina, moreover, the *ius gentium* was not
entirely a part of natural law, since it affirmed natural principles
but also embodied positive laws, including private property and
slavery. Generally, it was in the period between Vitoria and
Suarez that natural law was separated from the *ius
gentium*, further divided by Suarez into the *ius supra
gentes* (the law above nations) and the *ius inter gentes*
(the law among nations), which eventually became international law in
the strict sense. Natural law and *ius gentium* were quite
close to each other in Roman law and in Thomas Aquinas; but Vitoria,
in his commentary on *quaestio* 57 in the *Secunda
secundae* of the *Summa theologiae*, already maintained
that, for Thomas, the *ius gentium* was part of positive law.
Suarez makes it clear that, in contrast to natural law, which
is inscribed in the heart of human beings and is immutably valid for
all of them, the *ius gentium* is a positive convention among
peoples or nations, which is valid for all or nearly for all of them;
it includes the right to punish those who are defeated in a just war
and, therefore, also the right of enslavement (*De legibus* II
xviii 8).



It was furthermore the consensus among a majority of authors in the
School of Salamanca that no wars could be waged against non-Christians
by reason of their infidelity and that hostile actions could be
resisted in self-defense. As we have seen, however, this natural
immunity did not extend to permitting cannibalism or human sacrifice.
Molina, who favored the right to evangelize and permitted armed
protection for missionaries, was more wary than Vitoria of making free
commerce a right enforceable by war, using arguments which are
somewhat similar to those of Immanuel Kant, limiting
"cosmopolitan right ... to conditions of universal
hospitality" in his treatise *Toward Perpetual Peace*
(Kant 1795 [1996: 328-331; Ak. 8:357-360]). For Molina as
for Kant, the locals have merely charitable obligations towards those
who are arriving in their territories, if they are in need. They have
no obligation to open them their ports. Countries might refuse to
trade if they feared that commerce was an excuse for conquest (Molina,
*De iustitia et iure* II 105). Just wars could be waged by
rulers, but hating the enemy was prohibited. Subjects were obliged to
inquire about a ruler's decision to wage a just war if there was
"honest doubt" about it. Molina was willing to concede to
the pope a role mediating between Christian rulers, but he warned
against intervening directly in their squabbles.



One of the recurring questions with respect to the treatment of
indigenous peoples was whether their enslavement as slaves by nature
in the traditional Aristotelian sense was justified. As mentioned
above, a famous discussion of this issue took place at the Junta of
Valladolid, when the Aristotelian Juan Gines Sepulveda
debated with the Dominican Bartolome de Las Casas, an ardent
defender of the Amerindians and their rights. Sepulveda argued
that the Amerindians, as barbarians, were slaves by nature, more or
less on the level of beasts. Las Casas maintained that although there
were humans so simple-minded that they could be considered slaves by
nature, such people existed in Spain as well as in the Americas (Hanke
1959: 28-74).



Soto, who also participated in the debate in Valladolid, said that the
*ius gentium* was a universally applicable form of positive
human law, which was created by applying reason to natural principles.
This law governed trade, exchange of envoys and even slavery, if it
spared lives during war. It also included respect for property, even
of non-Christians, to avoid squabbles over possessions. Nor was
conversion a just reason for going to war and enslaving conquered
peoples.



Soto once considered going to the New World to resolve the
controversies there. Unable to go himself, he advocated sending good
missionaries. In addition, his writings were employed by the Third
Mexican Council (1585) in preparation of a confessors' manual
geared to a world of both Hispanic and Amerindian residents (Salcedo,
*Directorio para Confesores*). Soto's *relectio*
on dominion concluded that Spain's title to the Indies was hard
to justify. He rejected the opinion of Sepulveda on the justice
of waging war on infidels, also Pope Alexander VI's division of
overseas domains between Spain and Portugal. Soto was trusted by all
participants in the Junta of Valladolid to summarize the conflicting
opinions of Las Casas and Sepulveda, though he, or perhaps Cano
(Cano 1605), another critic of conquest, may have been the one person
who, according to Sepulveda, opposed him. The Dominicans of
Salamanca continued to argue for just conduct by Spaniards in their
overseas dominions; and also Jesuits like Molina, even in their
defense of slavery and slave trade, did not refer to the concept of
slaves by nature. Soto, though accepting slavery, rejected the idea of
natural slavery: in his view, human beings who were incapable of
leading their own lives clearly had to be guided by wiser men, but for
reasons of their own well-being, not as living tools in the
Aristotelian sense. So, slavery for him was merely conventional.



Molina, who wrote the first treatise on the Portuguese transatlantic
slave trade, followed Soto on this point, accepting only conventional
slavery. He justified slavery and mentioned the four just titles for
enslavement: committing certain crimes; being captured in a just war;
selling oneself because of urgent need; and the principle of
*partus sequitur ventrem*, that is, the children of enslaved
mothers also are slaves (*De iustitia et iure* II disp. 33).
Then he described the history of the Portuguese slave trade and gave a
critical evaluation of it (ibid., disp. 34-35). Interestingly,
although he dealt intensively with the transatlantic slave trade,
especially from Africa, he never put forward a justification for
enslavement based on race such as Noah's curse on the children
of Ham (Genesis 9:20-27) for mocking his drunken nakedness.



It may be, at first glance, astonishing that the impact of what we
today call race--as stated above, the term mostly used until the
second half of the eighteenth century was
"nation"--was increasingly used among the Jesuit
authors following Molina, although they were referring to his relevant
disputations (*De iustitia et iure* II disp. 33-40).
Alonso de Sandoval (1577-1652), e.g., who spent most of his life
in Cartagena (Columbia) and was named *defensor de los negros*,
wrote very doleful and touching passages about the terrible situation
of the black slaves in South America. But he had no doubt that their
enslavement was just, using Noah's curse as one of the reasons
for this (Sandoval 1627, I 2, I 3, I 17, II 2), Haar & Kaufmann
2023: Kap. 2.4.1.). Diego de Avendano (1594-1688) was
raised by the Jesuits in Lima, where he became professor of theology
and rector of the *Colegio Maximo de San Pablo de Lima*,
positions he held until his death. In his *Thesaurus Indicus*
in a section entitled "De contractibus Aethiopum", he
holds, on the one hand, that contracts with Africans on enslavement
bear an enormous risk for a Christian conscience because they hardly
ever fulfill the criteria of justice (Avendano 1668: Lib. I
Titulus IX, cap. XII. n. 180 [2001: 324]). On the other hand, he
declares that those contracts are "somehow"
(*aliqualiter*) justifiable for a number of reasons, one of
which is that Africans are born to serve and are the "least
among men" (*vilissimi inter homines*) (ib. n. 204, p.
330, Haar & Kaufmann 2023: Kap. 2.4.2.). Obviously, the
"necessity" of justifying the discriminatory treatment of
African people via their alleged shortcomings became more and more
urgent the longer the cruel exploitation, which contradicted all
humanitarian and Christian principles, lasted.


## 7. Economic Theory



Alongside the debates on just war, colonization and the slave trade,
economics is perhaps the most striking example of how the theologians
from the School of Salamanca used and transformed traditional medieval
theories in order to deal with new situations, creating innovative
solutions that had long-lasting influence. They have often been
mentioned as the ancestors of the Austrian School of Economics, which
in the late nineteenth and twentieth centuries emphasized the role of
the consumer's estimation in the development of prices and the
importance of the market against any attempt of rationally planning
economic processes, while Molina has been described as a "solid
economic liberal" (Rothbard 1995 [2006: 113]). This may be a
restrictive interpretation, because there is an undeniable relevance
of the medieval heritage with its rigid condemnation of usury to be
found in the authors from the School of Salamanca. Their views on
economy are founded in natural law, implying therefore a normative
view of economic processes instead of the purely strategic rationality
of a *homo oeconomicus*. Nonetheless, the general consensus is
that there are liberal elements in late Scholastic economics
(Schussler 2014). Among the topics they dealt with were public
finance, the danger of exhausting public treasuries and of excessive
taxes (Chafuen 2003: 53-60), the just price for different goods
and the problem of charging interest for lending money, which was
connected to the traditional condemnation of usury. The exchange of
money was another major issue, because there were a large number of
monetary systems simultaneously in use within the Spanish and
Portuguese kingdoms. According to Marjory Grice-Hutchinson, who
published an early and still important volume on their monetary
theory, the original contribution of the School of Salamanca in this
field consists 



> 
> 
> in its formulation of a psychological theory of value applied to both
> goods and money, of the quantity theory, and of a theory of foreign
> exchange that closely resembles the modern purchasing-power parity
> theory. (Grice-Hutchinson 1952: 47-48)
> 
> 
> 



A more or less common view of Spanish Scholastics on just price is
that the value of goods--and money--depends on estimation,
not primarily on the costs of production, nor on the needs of buyers
(Grice-Hutchinson 1952: 48-51). It is not the *communis
aestimatio* of theologians that determines the natural price, but
rather that of businessmen, as Molina says (*De iustitia et
iure* II 407); and it is not a fixed margin, but moves within a
certain range, depending also on the quantity of goods and money
available. Monopolies are criticized by Molina because they make such
a determination of just price impossible (ibid., II 345). Some authors
argued for a public limitation on the price of foodstuffs. Molina
favored support of the poor but hesitated to make only corn dealers
pay for it, because a fixed price would prevent merchants from
importing corn, thus damaging the common good (ibid., II 365).



The first formulation of the quantity theory of money is often
attributed to the jurist Martin de Azpilcueta, perhaps the best known
Salamancan writer on economic issues. In an appendix to his manual for
confessors, now published as *On Exchange* (2014), he discussed
exchange, supply and demand, and money. Azpilcueta attempted to
explain the rampant inflation of the sixteenth century as connected to
the large-scale importation of specie from the New World. Goods, he
argued, were more costly when money was abundant. This quantity theory
of money was widely accepted throughout Europe.



Azpilcueta, moreover, maintained that the exchange of money is not
unnatural, contradicting Aristotle and many Scholastics. He treated
money like other merchandise, positing that the morality of exchanges
which were not dependent on money as their object was equitable. There
were different questions connected to exchange. One of these was
whether, in the case of petty exchange, it was licit to take more than
the legally fixed commission; this view was rejected, and the legal
commission was seen as binding in conscience (Alonso-Lasheras 2011:
172-173.). Another problem arose in relation to exchange bills
because the value of money varied considerably between different
places within the Spanish Empire, offering new possibilities of making
and losing money. Spanish writers such as Azpilcueta and Molina
countered the suspicion of usury associated with this kind of business
by means of an early version of purchasing power theory according to
which the exchange rates between currencies are in equilibrium when
their purchasing power, i.e., what can be bought with a certain amount
of money, remains the same (Grice-Hutchinson 1952: 52-53;
Alonso-Lasheras 2011: 179). Concerning the topic of lending money,
authors like Molina justified taking interest, first, by the
*lucrum cessans*, the amount of money that the lender could
have made during the time it was on loan as a credit and, then, by the
*periculum sortis*, the risk that he might lose his capital
(Molina, *De iustitia et iure* II 315).



Despite the liberal elements which can be found in the works of
authors from the School of Salamanca, they nevertheless had a
completely different understanding of the market from that of modern
neoliberals. 



> 
> 
> The market was first of all a physical place in which real people came
> together. These people possessed a moral conscience that was also part
> of the economic process. (Alonso-Lasheras 2011: 169)
> 
> 
> 


## 8. Metaphysics and Logic



Spanish theologians were also involved in traditional discussions of
logic and metaphysics. Two representative examples will be discussed:
Soto's *Summulae*, a compendium on logic which is little
known today but which at the time was *the* compendium on logic
in the Thomist tradition, ordered and paid for by the University of
Salamanca in order to resist the influence of Nominalism; and
Suarez's famous and much studied treatise,
*Disputationes metaphysicae*.


### 8.1 Soto on Logic



Soto is regarded as responsible for the revival of Spanish-Thomist
logic, as distinct from both Renaissance-oriented logic, which used
only ancient sources, and the extremely technical
"sophistic" logic of Nominalism. His main sources were
Aristotle, Thomas Aquinas and Petrus Hispanus's *Summulae
logicales*, from all of which, however, he deviated in many areas.
In his *Summulae*, especially starting with the second edition
of 1547, which became one of the most influential textbooks of this
genre, he gives an introduction to traditional logic, including a
theory of terms, propositions and conclusions (Soto 1980). Whereas
Petrus Hispanus had been criticized for serious inconsistencies, Soto
gives his own interpretation, in an effort to build up a coherent
doctrine. In the presentation of the different kinds of terms, he did
not follow the Aristotelian categories, but instead presented the
medieval distinctions between mental, written and spoken terms,
between categorematic and syncategorematic terms (that is, terms that
have a meaning because they refer to things, concepts or other terms
and those which only make sense within propositions as connections,
but cannot be a subject or predicate, such as "if",
"all", etc.), between absolute and connotative terms, and
so on. He continued by presenting different kinds of proposition,
including a version of supposition theory--the doctrine of the
entities that the terms in a proposition, subject and predicate stand
for (ibid., 31-36). Here Soto also discussed Nominalist and
realist objections; but, in the end, he mostly defended the positions
of Petrus Hispanus, largely omitting, however, complicated types of
supposition such as distributive, confused, merely confused, etc.,
which had long puzzled medieval authors. The third book explains the
different kinds of relation between propositions, including an
extended version of the square of oppositions (ibid., 72), as well as
truth conditions for modal propositions, conjunctions and
disjunctions. In his discussion of the different kinds of valid and
invalid conclusion, Soto not only referred to syllogisms (book 5) and
the so-called *insolubilia,* or reflections on paradoxes (book
6), but also elements of the theory of *consequentiae*, a
medieval type of logical conclusion that may go back to the Stoic
logic of propositions (Read 1993; D'Ors 1983).



While the *Summulae* provide something like a basic
introduction to the logical topics discussed at the time, Soto's
*In dialecticam Aristotelis commentarii* (Salamanca, 1543)
contains philosophical reflections on questions such as whether logic
is a science and if so, what kind of logic, the *logica docens*
in contrast to *logica utens*, which is a "mode of
knowing", and whether the subject of dialectics is an *ens
rationis* (Di Liso 2000: 221-250). These reflections are
presented within the context of a selective commentary on the
Aristotelian Organon, omitting *De interpretatione* and the
*Analytica Priora,* which were treated in the *Summulae*
(ibid.). He also wrote *Super octo libros Physicorum
commentarii* and *Super octo libros Physicorum quaestiones*
as part of the *Artes liberales* course.


### 8.2 Suarez's Metaphysics



Suarez's *Disputationes metaphysicae* (1597) was
published in eighteen editions over a few decades in printing centers
throughout Europe--not only in Catholic, but also in Protestant
regions--and had an enormous influence on philosophy teaching in
European universities. It is still considered to be the most complete
and comprehensive presentation of *prima philosophia*; and it
was the most important link between Scholastic metaphysics and
seventeenth-century school philosophy, influencing Descartes, Leibniz
and Wolff. Although modern scholars debate the roots of the extremely
complicated system of metaphysics which Suarez presents in the
treatise, they seem to agree that he created a kind of synthesis of
Thomist and Scotist theories. Only a very general survey of the topics
discussed in Suarez's 54 metaphysical disputations can be
provided here, along with a brief mention of some of the most
important approaches to their interpretation.



Suarez's *Disputationes* do not follow the
structure of Aristotle's *Metaphysics*. Instead, he
starts with an extensive introduction to the Aristotelian treatise,
according to a slightly different order than in modern editions, and
indicates the precise places where the topics discussed there can be
found in his disputations. His first disputation reflects on the
nature metaphysics as *prima philosophia*. It is followed by
disputations on the concept of being (*ens*), its passions,
different understandings of unity, on the true and the false, and the
good and the bad. The pivotal role that these
"transcendentals" of medieval metaphysics play in
Suarez's metaphysics was the basis for the interpretation
of his theoretical philosophy as transcendental (Honnefelder 1990).
Next come sixteen disputations dedicated to the four Aristotelian
causes (material, formal, efficient and final), followed by the
various divisions of being (infinite and finite, uncreated and
created--including some kind of rational theology which discusses
questions such as whether God can be recognized with natural reason
(Disp. XXIX), whether there are physical proofs for God's
existence (Disp. XXX) etc.--and the division of created being
into substance and accidents). Then there are about twenty
disputations dealing with the Aristotelian categories, concluding with
one on the special theoretical problems associated with the concept of
*ens rationis*, which does not belong to any of the previously
discussed categories.



Interpretations of the *Disputationes metaphysicae* over the
last decades have all attempted to fit Suarez into a kind of
theoretical history (Darge 2004: 7-26). Gilson (1949) identified
an essentialism (according to the Thomist distinction between
*ens* and *essentia*) that neglects the act of being in
favor of a purely abstract conceptualization and that can be traced in
a line of thinkers from Avicenna through Duns Scotus and Suarez
to Wolff and Kant. Honnefelder (1990) sees Suarez as dependent
on the same earlier philosophers, but he does not present it as a
history of decadence from a Thomist perspective, as Gilson did, but
rather as a success story for the transcendental Scotist approach.
Scotus uses a univocal instead of an analogous concept of being for
created and uncreated substance (i.e., God) and individuates the realm
of what may be meant by "being", based on the most general
understanding of being as "*id cui non repugnat
esse*", i.e., the existence of which does not imply logical
contradictions. Furthermore, he gives a modal explication of the
different grades of finite and infinite being including the existence
of finite and infinite substance. Courtine (1990) and Boulnois (1999)
share this "Scotist perspective", but they see it more as
a move from the science of what is to the science of what can be
thought, that is, an onto-logic. Precisely in the years when the term
"ontology" was coined by Rudolf Goclenius (Lamanna 2014),
it no longer referred to the "furniture of the universe",
as Putnam (1985: 28) called it, but instead to ways of thinking and
speaking about the things in the world--a process that ends with
the determination of what is through our speaking about it. Darge,
finally, tries to free Suarez from this purely logicistic
interpretation and from the Scotist perspective, in order to emphasize
his innovative merits against his classification as an intermediate
figure between Duns Scotus and Thomas, on the one hand, and Wolff and
Kant, on the other. There is no doubt, however, that
"Renaissance and Baroque Scholastic culture", to which
Suarez doubtlessly belongs, has finally become an object of
serious research (Novak 2014: 2). This research is not only
providing a general systematization and historical integration of
Suarez's metaphysics, but also investigating particular
aspects of his extremely rich theory (B. Hill 2012; Novak
2014).


## 9. The Influence of the School of Salamanca



It is difficult to give a precise evaluation of the influence of the
School of Salamanca in the many fields to which it contributed. There
are various ideological motives, apart from the general tendency to
conceal one's sources, why later authors did not mention these
theologians. This was especially the case for philosophers,
theologians and legal theorists from the Protestant North with their
aversion to Catholic thinkers, and especially Jesuits. Quarrels arose,
for instance, as to whether the Dutch jurist Hugo Grotius
(1583-1645) was the father of modern natural law and
international law or whether he only copied and slightly altered the
works of Suarez and other Spanish authors. Another pertinent
issue is that Suarez was regarded as *the*
representative of "the schools", to which the founders of
modern philosophy opposed their new philosophical systems, often
denying their heritage. Some works by Spanish Scholastics therefore
fell into oblivion. In recent years, however, the ideological barriers
have vanished, and there is a growing interest in an open-minded
discussion of the School's achievements and impact.



As has been indicated, the School of Salamanca is credited with a role
in the development of international law. The gradual detachment of the
*ius gentium* from natural law, particularly as it pertained to
issues such as slavery and the slave trade, was another notable
accomplishment; so too, was its consistent defense of the full
humanity of the Amerindians. That argument could be applied to other
non-European peoples who had also never heard of Jesus; their regimes
and property rights were closely tied to reason and natural law.



The School, in addition, made important contributions to areas such as
trade and finance. Azpilcueta's approach to inflation and his
defense of the morality of exchange was a step toward a culture of
accepted risk and profit. Vitoria's argument that commerce fell
within the *ius gentium* was not embraced by everyone in the
School; but this argument had a direct influence on Grotius. Moreover,
although a Protestant and an opponent of papal claims to temporal
power, Grotius drew on Thomas Aquinas, Cajetan, and Vitoria to argue
for the freedom of the seas and to develop a framework for
international law. Because of the School's role in the
development of economic theory, some economists, including those
belonging to the Austrian School of National Economy, refer to them as
their ancestors.



Suarez and Mariana formulated theories of resistance to
unacceptable rulers, which Roman Catholic thinkers engaged in opposing
Protestantism and Protestant rulers like James I found attractive. In
the heated atmosphere of the times, it is possible that these theories
may have inspired the Catholic fanatics who assassinated Henry III
(Valois), Henry IV (Bourbon), and William the Silent (Nassau). Similar
theories were also developed by Protestant writers, including French
Huguenots and Calvinists in the Low Countries.



Members of the School of Salamanca departed from Aristotle and Thomas
Aquinas as they saw fit. This is apparent in Soto's logic and
Suarez's widely read metaphysics. Less noted until
recently is the influence of Soto on Galileo. Diverging from
Aristotle, Soto advanced theories that have been described (Duhem
1913: 193) as forerunners of the modern idea of mechanics. His theory
of falling bodies was well known to Jesuit scholars, who circulated it
through their writings. As a young student, Galileo was probably
exposed to these ideas, which influenced his approach to the physical
laws governing the universe (Wallace 1981 and 2004). Galileo's
theories about falling bodies eclipsed Soto's, while his
astronomical observations helped to create a heliocentric and
un-Aristotelian intellectual milieu, in which many ideas of the School
of Salamanca were regarded as obsolete. Even in Spain,
the *novatores* thought the Scholastics were no longer
relevant, not even having read Descartes (Gomez Paris
2022: 563, 570).



Starting in the 1930s, with the work of James Brown Scott and others,
the School of Salamanca gained renewed attention for its contribution
to ideas of international law, including respect for non-Christian
peoples. Academic interest overcame old prejudices tied to
Europe's past confessional and ideological divisions. The
interest of economists in monetarism also placed Salamanca in the
scholarly mainstream. The revived study of Scholasticism has drawn
attention to Soto, Molina and Suarez, while modern editions,
including those in the series "Corpus Hispanorum de Pace",
have made these thinkers more accessible to a new generation of
scholars.