The Aristotelian doctrine on earthquakes

Up to the late 17th century in the west, ideas about the origin of earthquakes were based on the Aristotelian doctrine. Aristotle (384–322 bc) proposed his doctrine on earthquakes in the Meteorologicorum Libri IV. In these books he considered various phenomena, such as rain, clouds, thunder, lighting and winds, now included in the modern science of meteorology, but also comets, the Milky Way and earthquakes. According to Aristotle, earthquakes were produced by the dried exhalations (spirits or winds) trapped in cavities inside the Earth trying to escape toward the outside and making the Earth shake. The winds (pneuma) were introduced from outside or generated inside these cavities. For this reason, Aristotle considered that regions with abundant caves or cavities in the Earth were more prone to earthquakes. In his treatment of these phenomena there was no mention of anything mysterious or supernatural in their occurrence. Pliny the Elder and Seneca, two Latin authors of the first century, were very influential in the early Middle Ages, and they presented this Aristotelian doctrine with some minor changes. Early Christian authors, such as St. Isidore of Seville in the seventh century and the Venerable Bede in the eighth century, repeated Pliny's and Seneca's ideas. They also wrote nothing about divine intervention in earthquakes. Between the 12th and the 13th century, Aristotle's works were translated into Latin, first from Arabic and then from the original Greek. University professors from this period wrote commentaries on the treatises of Aristotle including the Meteorologica. Two of the most important 13th-century commentators on Aristotle were Albertus Magnus and Thomas Aquinas. Albertus wrote a long commentary, divided into 20 chapters, on the subject of earthquakes, but he never mentioned that earthquakes are signs of God's wrath (Albertus Magnus 1890). Aquinas, known especially for his monumental theological work, wrote a more literal commentary, including Aristotle's Greek text and its Latin translation. He also did not include any religious commentaries on earthquakes. Because of his influence on later Catholic authors, it is important to search in his other works for religious considerations of earthquakes. The only place where these are found is in his commentary on Psalm 17, discussing the verse: ‘The earth swayed and quaked; the foundations of the mountains trembled and shook when his wrath flared up.’ First, he affirmed that the first cause of the motion is divine will. Second, he stated that assignment of earth tremors to divine wrath is only metaphorical (hanc exprimit metaphorice) and the intention to move men to penance has to be understood in a mystical sense (mystice designatur per hoc commotio hominum ad poenitentiam). In the following paragraph, he explained the origin of earthquakes according to Aristotelian ideas. Thus, his authority cannot be cited to support that earthquakes were thought to be caused by divine wrath (Aquinas 1918).

Aristotle's doctrine was predominant in western universities in the 16th to 18th centuries. Among the Spanish commentators on Aristotle's Meteorologica was Alfonso Perez (1576), who dedicated three chapters to the subject of earthquakes. The only reference to God's intervention he made was in respect to the earthquake at the time of Christ's death. Perez considered this earthquake to have been caused directly by God as a sign of the reaction of nature to the death of Christ on the cross. Francisco Murcia de la Llana (1615) wrote a more extended commentary on earthquakes, giving a detailed list of 12 effects produced by them. He stated that the first was the fear and terror they produced, and added: ‘God makes everything in order to bring to His service those who live having forgotten it.’ This was his only mention of this subject. Francisco Alfonso (1641), a professor in the Jesuit College of Alcalá, published a third commentary. He added to the Aristotelian doctrine the presence inside the Earth of inflammable materials such as sulphur and bitumen as the cause of subterranean fires. Again, there was no mention in his work of God's intervention.

Spanish authors before the Lisbon earthquake

Criticism of Aristotelian ideas on other subjects by the proponents of modern science extended also to the origin of earthquakes. Martin Lister in England in 1648 and Nicolas Lemery in France about 1700 were the first to propose that earthquakes were produced by large explosions of inflammable material formed by a combination of sulphur, coal, nitre and other substances accumulated in the Earth's interior. The explosive theory became very popular, and can be found also in Newton's Optics (1718) and Buffon's Histoire naturelle (1749–1788) (Taylor 1975). In Spain these ideas were mixed with organicist points of view, in which the Earth was compared with a living organism. In this respect there was an important influence on Spanish authors by Athanasius Kircher (1601–1680), a Jesuit professor at the Collegio Romano, especially in his work Mundus Subterraneus (1664) (Glick 1971; Capel 1980). Kircher proposed the existence in the interior of the Earth of three systems of conduits through which fire, water and air circulated. He called these systems pyrophylacia, hydrophylacia and aerophylacia. The first were related to the volcanoes and connected them with a fire in the centre of the Earth. Kircher thought earthquakes were related to these systems of conduits, with fire heating the air, which then expanded, causing the Earth to tremble. He added also the explosion of inflammable materials.

José Zaragoza, a professor of mathematics at the Jesuit Imperial College of Madrid, was considered to be one of the best Spanish mathematicians of his time, and he treated the subject of earthquakes in his work on astronomy and geophysics (Zaragoza 1675). After explaining the Aristotelian theory and Kircher's ideas, he added: ‘It seems more according to Christian Philosophy that many times earthquakes are a natural effect and at other times God causes them, or lets the Demon do it, in order to punish men.’ This is an explicit mention, in a purely scientific work, of God's intervention in earthquakes, although Zaragoza stated that only on some occasions could they be directly attributed to God as a punishment. It is interesting that Zaragoza considered, as another possibility, that sometimes God may permit the Devil to cause earthquakes. Tomás Vicente Tosca, a priest of the Oratory, in his monumental nine-volume work Compendio mathematico, wrote a short chapter on earthquakes (Tosca 1707–1715). He explained that earthquakes were caused by explosions of inflammable materials inside the Earth similar to those in mines; he did not mention God's intervention in them. This is also the case in the physics treatise of Andrés Piquer (Piquer 1745).

Diego Torres de Villarroel, a professor at the University of Salamanca, published the first complete work on earthquakes in Spanish (Torres de Villarroel 1748). In this lengthy treatise, in which Kircher's organicist ideas were mixed with the explosive theory, there was only a short mention of the religious problem. After describing the destructive power of earthquakes, which ‘level buildings and mountains and destroy cities and provinces’, Torres de Villarroel wrote that these phenomena seem to be preternatural and can be considered as miracles, concluding, ‘we can believe that they are God's wrath, punishment and … inflicted by His Majesty for our sins and in this way they are described by Catholic physicists’.

Another group of Spanish authors who considered earthquakes are those writing about the newly discovered lands of Central and South America, where large destructive earthquakes are common. They wrote for the learned public, presenting the natural aspects of the new lands. Four of the most important of these authors were José de Acosta (1590) and Bernabé Cobo (1890), both of whom were Jesuit missionaries, and Antonio de Ulloa and Jorge Juan, who were naval officers and scientists participating in the measurement of the meridian at the equator (de Ulloa & Juan 1748). This effort was organized by the French Academy of Sciences. The authors described some of the largest earthquakes in Peru and Chile, which had been followed in some cases by tsunamis. They speculated about the nature of earthquakes in similar terms to other contemporary Spanish authors, but did not make any reference to God's intervention. This is important because some of the earthquakes described caused thousands of casualties, and for de Acosta and Cobo they would have been a suitable occasion for a religious consideration.

The 1680 Malaga earthquake

It is one thing to write about earthquakes from the academic point of view, but a very different thing to do it after first-hand experience of a damaging shock. On 9 October 1680 a destructive earthquake took place with its epicentre near Malaga. It caused 60 deaths and injured 150 people, and caused widespread destruction in the city and nearby towns. Its magnitude has been estimated as M_s=6.5 (Muñoz & Udías 1988). Six days later the bishop of Malaga, Alonso de Tomás, wrote a long pastoral letter in which he made it very clear that the earthquake had been caused by the many sins of the people of Malaga. In the first paragraph he expressed the idea that the cause of so much distress was human sins, and suggested that the calamities and horrors were the effects of our evils, which forced God to make us experience his punishment. In the rest of his commentary he provided many quotations from the Bible and exhorted his readers to change their lives and make penance so as to be reconciled with God. At the end he ordered all the priests of his dioceses to make public penances and atone for their scandals and sins; religious processions were made in all churches the following Sunday (de Tomás 1680). An anonymous popular description of the earthquake, published shortly afterwards, began with a sentence declaring that the cause of the earthquake had been many sins and that the justice of God had laid the harshness of his wrath upon the people. The description then considered that God has used the creatures that benefit men to be instruments of their ruin, terror and fright (Anonymous 1680a). In another publication of the same type, which related how the shock was felt in Madrid, the earthquake, together, with other calamities, was considered as a warning from God to make penance and repent of evil customs. It was stated that through these events God desired that men turn to him (Anonymous 1680b).

Most other documents of popular character recounting the damage of the 1680 earthquake accepted it as a clear sign of the displeasure of God and a punishment for the sins of the people. There were no dissenting voices and no attempts to refute this idea. Although we have seen that at that time university professors in Spain explained the natural causes of earthquakes using Aristotelian natural philosophy, we have not found any document that applied those ideas to this actual earthquake. The only document with a known author, signed by the Priest Antonio de Cea y Paniagua, concerned how the earthquake was felt in Cordova. The author, an arts graduate, refused to give a natural explanation, and wrote: ‘we will omit the philosophical question (fruitless here) about the cause of earthquakes, when for the knowledge of piety in the First Cause against the obvious bitter acts of his justice, the clear testimony of his clemency is enough’ (de Cea y Paniagua 1680). He recognized that there were also natural causes of earthquakes, but they were not applicable to this case. He considered pertinent only the religious considerations.

The earthquake occurred during the reign of Charles II, the last king of the Spanish Austrian dynasty; this was a time of cultural and economic decay and of exacerbated religious fervour. This has been often presented as the reason behind referring to the earthquake as a supernatural event (Pereiro Barbero 1986). However, evoking the wrath of God immediately after an earthquake was not an exclusively Spanish phenomenon of the time. Similar ideas were used then by Protestant preachers in England. For example, Thomas Doolittle, the Puritan minister of St. Alphage, London, in his sermons after the London earthquake of 1692, distinguished between earthquakes that were caused indirectly and directly by God. The latter provoked the human response of fear, trembling and immediate contrition. Doolittle called it ‘holy fear’, that is, an activating fear that produced moral benefits: the greater the fear, the more intense the reforming piety (van Wetering 1982). Thus some earthquakes, including the London 1692 event, were directly attributed to God with a religious purpose. However, this was not a universal attitude of religious considerations of the time. A clear contrary example was the reaction of Gaspar de Villarroel, Bishop of Santiago de Chile, after the catastrophic earthquake of 13 May 1647, which totally destroyed that city. Reflecting on whether the earthquake could be considered as a punishment of God for the sins of the people of Chile, he gave the contrary answer: ‘whoever has seen the ruin of Santiago will not proceed with the sincerity that teaches the Gospel if he dares to judge that this earthquake was a punishment of the citizens’. He added: ‘This is so in agreement with a good theology and God's law so that it will be a mortal sin to judge that their sins destroyed this city’ (Amunátegui 1882).

Although, both Catholic and Protestant clergy in the 17th century, used the occurrence of earthquakes to move people to repentance for their sins, they did not ignore the theories about the natural origin of earthquakes, based on either Aristotelian doctrine or the newer proposals involving inflammable materials inside the Earth. The religious considerations were presented at the same time as natural causes were given. The recourse to God's action was not a substitute for the natural explanations, which were fully understood according to knowledge of the times, but was a recognition of the special action of God in certain cases.

The Lisbon earthquake of 1755

The Lisbon earthquake of 1 November 1755 was felt over the whole Iberian peninsula. It caused heavy damage and about 2000 casualties as a result of both the earthquake and the subsequent tsunami especially in the nearby cities of Huelva, Cadiz and Seville (Martínez Solares & López Arroyo 2004). This extraordinary event produced an abundant literature published in Spain, especially in Seville. Many publications were short popular accounts of how the earthquake was felt in a single locality, and many included religious considerations motivated by the event. Most of these anonymous publications were generally short works of a few pages, and were of a popular character, with exaggerated narratives of damage or curious occurrences supposed to have taken place during the earthquake. Some of the accounts were written in verse. Many were predominantly of religious character, asking for help from God, or giving thanks to God for the deliverance from the effects of the earthquake. We have identified 49 of this type of publication.

Other publications belong to the academic category, and some were extended treatises on the physical, philosophical and theological aspects of the event. They were written by natural philosophers and theologians, many of them university professors. Most of these authors handled two main questions. The first was whether this was a natural event or a supernatural one, that is, one directly attributed to God. The second was about the natural cause of this earthquake and the origin of earthquakes in general. A special point discussed was how it was possible for the earthquake to be felt at the same time in widely separated regions. On this second question, traditional and new ideas about the nature of earthquakes were discussed and debated.

Natural or supernatural event

The occurrence of the Lisbon earthquake generated in Europe an intense debate about what has been called ‘eighteenth-century earthquake theology’ (Kendrick 1955). At the centre of this debate was the opinion, generally asserted by many of the clergy, both Catholic and Protestant, that the earthquake was a deliberate punishment by God of sinful people. A constant theme in sermons, tracts and moralizing poetry, throughout Europe was that God in his anger had destroyed Lisbon because of the sins of its inhabitants. In Portugal the debate was intense, with, among others, the Jesuit Gabriel Malagrida on one side and Sebastian José de Carvalho e Mello, Marquis of Pombal, the powerful minister of King José, on the other. Malagrida took an extreme position and insisted in his sermons that the earthquake had been caused by the wrath of God for the sins of the people of Lisbon. Pombal, who took a pragmatic attitude to organize the care of the victims and oversee the reconstruction of the city, regretted the sermons of the clergy and especially those of Malagrida. In his opinion such statements only led to passivity in the people. Pombal ordered that Malagrida be sent to prison, 6 years later to be executed by the Portuguese Inquisition.

In France the earthquake caused questions about the generally sensed optimism of the times, which held that the world was a good place in which everything that happened was viewed to be ‘for the best’. François Marie Voltaire, in his Poème sur la désastre de Lisbonne and his novel Candide, wrote a strong attack on this optimistic viewpoint. On the other side, authors such as Jean Jacques Rousseau defended the optimist position, and rejected Voltaire's gloomy picture of man's unhappy fate on Earth. In Germany Immanuel Kant, adhering to Gottfried Wilhelm Leibniz's optimistic theodicy, which held that this was ‘the best of all possible worlds’, published three short papers on the Lisbon earthquake in 1756. He was more interested in the scientific aspects of the phenomenon, but touched also on the subject of earthquakes in relation to God's government of the world. The optimist position was heavily wounded by Voltaire's sharp attacks in Candide. Voltaire's negative position finally carried the day in the Europe of the Enlightenment (Kendrick 1955).

In Spain the debate was centred on the supernatural or natural character of the earthquake, and the discussion began a few days after its occurrence. Popular anonymous publications were generated and sermons in the churches were given, in which the supernatural character of the disaster was presented. Some of them asked for the help of heavenly patrons, or thanked various saints for their protection, among them of the Virgin Mary, St. Francis of Borgia (by the Jesuits), St. Philip of Neri (by the Oratorians), and St. Justa and St. Rufina, patron saints of Seville (by the non-monastic clergy). Many of the anonymous popular publications had a similar theme and many of them were published in Seville. Most of them took it for granted that the earthquake was God's punishment for the sins of the people. Thus, public religious services were organized in the days immediately following the earthquake (Aguilar Piñal 1973). As we have seen, 75 years before the Lisbon event, the earthquake that destroyed Malaga in 1680 was generally thought to have been a punishment by God, with no dissenting voices.

The two sermons of Francisco Olazaval y Olayzola, the Canon of the cathedral of Seville, of 27 April 1755 and 28 February 1756, are examples of purely religious literature. Olazaval y Olazola insisted that the many sins of the city of Seville were the cause of this punishment, which the mercy of God had not permitted to be even greater (Olazaval y Olayzola 1755). Agustín Sanchez, a Trinitarian theologian and preacher, in a note included in Francisco Mariano Nifo y Cagigal's work, insisted ‘God uses the creatures to infuse fear in sinners and move them to repentance’ (Nifo y Cagigal 1755). Even three years later, José Martin Guzman's sermons insisted on this interpretation. The firmest defender of the supernatural character of the earthquake was Miguel de San José, the Bishop of Guadix and Baza (Granada), who published a short letter in which he refuted the opinions of those who regarded this as a natural event, especially de Cevallos, and affirmed that: ‘only to deny or doubt that earthquakes and other disasters are usually the effect of the wrath of God, can be considered as an error in the faith’ (San José 1756). Similarly, a short letter of Thomas del Valle, the Bishop of Cadiz, called attention to the sins of the people of Cadiz, noting that God had punished them and called for their repentance (del Valle 1755). Francisco Javier González, a friar of the Minims Order, confronted this rigid position and wrote, answering the bishop, that God does not need to interfere with nature. González related this kind of disaster with sins only in a very general form, as a consequence of the original sin (González 1757).

In contrast to what happened after the Malaga earthquake, by 1755 there was serious questioning about attributing the earthquake to a direct action by God. José de Cevallos (1726–1776), a theologian from Seville and later the Rector of the University, was the strongest defender of the position that the earthquake was a natural event. He was a founding member of the Real Sociedad de Sevilla and of the Real Academia de Buenas Letras, two learned societies of Seville, where enlightened ideas were discussed. De Cevallos expressed his position in his introductory note (Censura) to Benito Jerónimo Feijoo y Montenegro's work, where he concluded; ‘the earthquake has been entirely natural, caused by natural and proportioned second causes, in which God partakes as in any other natural effect’ (Feijóo y Montenegro 1756). He refuted the opposite opinion as being theologically unsound, and insisted that ‘if preachers didn't have their devotion and zeal ruled by wisdom and discretion, they will produce disordered effects and false believes’. De Cevallos also refuted those who considered it a heresy to maintain that God does not cause earthquakes, basing this opinion on the catalogue of heresies by Saint Philaster, an Italian bishop of the fourth century. He noted that most other religious writers did not hold this opinion. Juan Luis Roche, a physician born in Catalonia and established in Seville, defended the same opinion, adding that there was no relation between sins committed and the occurrence of earthquakes. Rhetorically he asked: ‘Are Lisbon and Seville worse than other cities?’ For him those considerations were only ‘pious opinions of theologians’. Roche censured the theologians who attacked the physicists (physicos) who explained these phenomena by purely natural principles (Feijóo y Montenegro 1756).

The natural character of the earthquake was defended and discussed in several lectures at the Real Academia Sevillana de Buenas Letras, founded in 1751, which served as a forum for new ideas. Several similar institutions were established in Spain at this time, when most universities in Spain were still attached to traditional views. Roche held the first lecture on the earthquake on 12 November 1755 (Sobre el terremoto del 1 de Noviembre). The following year there were lectures by Jerónimo Audixe de la Fuente (Formación y efectos de los terremotos, 27 March 1756) and by Francisco de Céspedes Espinosa (Relación histórica del terremoto de 1755, 17 September 1756). These discussed the occurrence of the earthquake from a secular perspective. Although priests took part in these conferences, there were no formal theological discussions at the Academia (Sánchez Blanco 1999).

Both de Cevallos and Roche supported their opinions with the authority of Benito Jerónimo Feijóo y Montenegro (1676–1764), a Benedictine professor of theology of the University of Oviedo and a key figure in the Spanish Enlightenment, who was the author of Theatro crítico universal (1726–1740) and Cartas eruditas y curiosas (1742–1760), two very influential works in the introduction of scientific ideas in Spain. Feijóo y Montenegro defended the natural character of the earthquake, but, already an old man, did not enter the controversy. He wrote that man should fear sudden death more than earthquakes, since the former is more common.

Another defender of the natural character of earthquakes was Antonio Jacobo del Barco y Gasca (1716–1783), a priest and historian of Huelva, whose main work was dedicated to the history and agriculture of the region. Del Barco wrote that he intended to study ‘as a philosopher’, the causes, duration, extension and effects of the earthquake. Defending its natural character, he added that natural did not mean ‘casual’, and this type of occurrence had to be used as an occasion for men to turn to God (del Barco 1756). Isidoro Ortiz Gallardo de Villarroel, the Professor of Mathematics at the University of Salamanca, explained the natural causes of the earthquake and did not want to enter into the theological question of whether or not it was a warning from God (Ortiz Gallardo de Villarroel 1755).

Some authors held a mixed position, commenting that the earthquake was a natural event, but God could have used it to punish or warn sinners. Miguel Cabrera, of the Order of Minims, a theologian of Seville, claimed that the earthquake was ‘natural in its causes, in its being and in its consequences’, but, a special providence could have ordered it to happen at a particular place and time (Cabrera 1756). Francisco de Buendía y Ponce (1721–1800), a priest from Seville, poet, physician of the Archbishop of Seville, and the author of works on history and medicine, held the same opinion (Feijóo y Montenegro 1756). He stated that earthquakes, although produced by natural causes, could be sometimes a ‘punishment by the Divine Hand’. Francisco Martinez Moles, a professor at the University of Alcalá de Henares, who argued that earthquakes could be signs of divine wrath, took a similar position (Martínez Moles 1755). He wrote, ‘if this was a natural phenomenon caused naturally, it can be investigated rationally’. However, he went on to suggest that there were reasons for saying that God had ordered the earthquake as punishment for sins. Francisco Mariano Nifo y Cagigal (1719–1803), founder of the first newspaper in Madrid, held a similar view (Nifo y Cagigal 1755). After explaining the natural causes of earthquakes, he added what can be considered their moral causes and effects, noting that God could use these phenomena as warnings to sinners for their repentance. Juan de Zúñiga, in a letter to Feijóo y Montenegro, explained the natural causes of earthquakes and commented on how God used natural causes to show his displeasure of man's sins (Feijóo y Montenegro 1756) by De Zúñiga (1756). Pedro Trebnal, a member of the learned societies of Seville, after giving the details of this debate in his unpublished long manuscript on the subject, gave a twist to the problem by rejecting the supernatural character and defending it as a natural event, but suggesting that it was not entirely so because it had a preternatural character. That is, some evil spirit may have produced the earthquake (Trebnal 1756).

In conclusion, in Spain there were defenders of both opinions about the natural or supernatural character of the earthquake. Authors holding the new ideas of the Enlightenment (called in Spain ilustrados, many of them clerics) contended that the earthquake was a purely natural event, and should be studied from the purely natural point of view, staying away from theological considerations. On the other hand, traditionally minded clergymen maintained that the earthquake was a punishment or warning of God to sinners. Even as late as 1784 a Dominican friar, Alvarado, wrote that: ‘we prefer to be mistaken with St. Basil and St. Augustine than to be correct with Descartes and Newton’ (Aguilar Piñal 1973). An intermediate position was also presented, in which the earthquake was thought to be a natural phenomenon but God's providence used it to warn sinners. Authors taking this position argued that men could infer moral consequences from a natural event. Sanchez Blanco (1999) summarized the debate as one between two philosophical positions, a theistic position in which God intervenes directly in natural phenomena, and a deistic position in which God has given laws to the universe, but does not intervene in its normal working. However, Spanish authors, such as de Cevallos and Roche, who defended the concept of the earthquake as a natural phenomenon, cannot be called deists, as they held to the Christian tradition of divine action in the world. All participants in the debate considered themselves to be faithful to Christian doctrine and did not deny the possibility of divine intervention in the world. Moreover, there was no reference to the philosophical debate in Europe about an optimistic or pessimistic view of the world. Spanish authors never mentioned Voltaire, Leibniz, Kant or any other participant in this debate.

The authors who held that the earthquake was a natural phenomenon took this occasion to explain the general causes of earthquakes. In their explanation we can see to what extent they knew about the scientific ideas being developed at that time in Europe. At the end of the 17th century and beginning of the 18th century new theories about the origin of earthquakes were proposed that replaced the traditional views founded on Aristotelian doctrine. In the writings of Spanish authors after the Lisbon earthquake we find a variety of theories proposed, ranging from those based on the traditional Aristotelian doctrine to the ideas introduced by recent authors (Ordaz 1983). Cabrera, Nifo y Cagigal and Trebnal presented the most traditional point of view and defended the Aristotelian doctrine, with some modifications, against the attacks of recent authors. In their explanations they introduced ideas in which the Earth is compared with a living organism, thereby showing Kircher's influence. Some authors, such as del Barco y Gasca, Roche and Ortiz Gallardo de Villarroel, adhered to the theory of the explosive nature of earthquakes. Feijóo y Montenegro, in his five letters, presented the most original ideas about the origin of the earthquake. He stated that, in the same way as lightning and thunder are produced in the atmosphere by the electricity of the clouds, earthquakes are caused by the electricity accumulated inside the Earth by vitreous material. This was not a totally original idea, as William Stuckley in England in 1750 and Giovanni Battista Beccaria in Italy in 1753 had already proposed the electrical nature of earthquakes (Taylor 1975).

Conclusion

The interpretation of earthquakes as God's punishment for sins, in Spanish writings of 17th and 18th centuries, has been examined using the occasions of the Malaga earthquake of 1680 and the Lisbon earthquake of 1755. After the 1680 earthquake, this interpretation was generally held with no dissenting voices. After the Lisbon event, however, Spanish writers joined the rest of Europe in debating the natural or supernatural character of the earthquake. Authors took positions on both sides of the controversy. Some, such as del Barco y Gasca, Roche, de Cevallos and Feijóo y Montenegro, defended the natural origin of the earthquake. They stated that this position was not against Christian doctrine, so that their position cannot be called deist. On this occasion authors also tried to explain various theories about the origin of earthquakes, ranging from Aristotelian doctrine to organicist theories, and to explosive and electrical theories.