A Feminist Physiology: B. J. Feijoo (1676–1764) and His Advice for Those in Love

This essay analyzes how the Benedictine monk Benito Jerónimo Feijoo (1676–1764), one of the most popular Spanish natural philosophers in Europe and America, discussed amorous attraction. In an attempt to reconcile Catholic dogma with empirical knowledge, Feijoo explained the origin of love as the result of wave-like interactions between sensual stimulus, imagination, nerve fibers, and the heart. His physiological model considered men and women to be equal in their internal constituents, which had important consequences for a possible science of matching. First, a possible match could only be known by a physical encounter; second, love bonds could be controlled by training the imagination; third, a harmonious society with happy marriages required accepting the intellectual equality of the sexes. The essay suggests how our knowledge about the nature of emotions influences the way we imagine an ideal society, as it is ultimately about the forces that attract and separate people, as well as the mechanisms to control them.

Unlike the other figures considered in this Focus section, who sought a means to predict the success of matches, Feijoo's interests lay in the amorous bond itself: how it is formed, what changed in the interior self because of the other, and what should be done to maintain or to extinguish the amorous flame. He was interested in dissecting what happens in the flesh and soul of those who fall in love, in their brains, nerves, hearts, and sexual organs. As he put it, he was concerned with "the physical, the natural philosophy" of love. 2 Feijoo believed that passions were the product of a contingent relationship between the soul, the flesh, and the external world. His physiological model excluded the possibility of knowing whether two people would fit together until the precise moment of their physical encounter. Only in face-to-face moments, when two souls "see" each other-or, more precisely, "feel" each otherwould it be possible to know whether a match would occur. Although this process of feeling occurred involuntarily, Feijoo did reserve room for a certain agency: there were strategies by which one might manipulate one's own amorous feelings. To put it differently: Feijoo rejected matching as a science of prediction, while nevertheless seeking to elucidate techniques for controlling passionate bonds.
My interest in exploring Feijoo's ideas is twofold. On the one hand, he was arguably the most influential thinker of the eighteenth century in the Hispanic world and the most widely known outside its borders. 3 His aim when he took up the pen at the age of fifty was to combat "erroneous philosophical opinions." Tremendously successful, he was compared by his contemporaries to the secretary of the Paris Royal Académie des Sciences, Bernard Le Bovier de Fontanelle, for his ability to state "difficult issues in simple language" and, above all, because he "encouraged lay people to think." 4 For his followers, Feijoo represented the acceptable face of the Enlightenment, one that reconciled Christian faith with the empirical sciences. Literarily gifted, a holder of high offices (he held the chair of theology in the University of Oviedo), tightly connected with intellectual elites, and well aware of scientific developments, Feijoo was in an excellent position to undermine the scholastic thinking that still pervaded the university and ecclesiastic quarters. 5 The first volume of his Teatro crítico universal (1726), comprising sixteen short, thrilling essays, was a bestseller. It was followed by eight additional volumes and by five tomes of Cartas eruditas y curiosas (1742-1760), a collection of even briefer pieces that supposedly responded to his readers' questions. 6 Feijoo's opinions provoked heated debates that ceased only in 1750, when the Spanish king, Ferdinand VI, prohibited attacks against him. More than ninety editions of his works were published before his death, astonishing numbers for the Spanish market, and his writings circulated widely in different languages across Europe and the Americas. 7 At the same time, what is remarkable is not only that Feijoo was extremely popular but that his physiological model considered men and women to be intellectual equals, with significant consequences for his views on matching. Feijoo defended what we could call a "feminist physiology" in the sense employed by Ian Maclean and Gianna Pomata-a physiology in which female bodies are not seen as inferior or imperfect copies of male ones (as was the case in Aristotelian theories and in some Galenic views) but, rather, as possessing the same intellectual capacities. 8 This had practical consequences: for instance, the conclusion that having an amorous nature was not something particular to women. Moreover, for Feijoo, happy marriages would only be possible if men and women recognized themselves as having the same intellectual capacities. 9 Like other reformers of his time, Feijoo supported "marriage based on inclination," which in this context balanced sentiments with social and material aspirations. 10 Feijoo's unique position in this discourse lay in his claim that the only way to achieve lasting marriages was first to recognize that there were no differences in the workings of men's and women's bodies.
Feijoo's ideas complicate the narrative scholars have told about how bodies were progressively gendered during the eighteenth century, wherein female bodies were accorded greater sensibility than male ones, particularly in amorous and sexual matters. This essay thus adds to recent historiography that has shown that several, in part even contradictory, models of male and female bodies coexisted at the time, especially if one focuses on different written genres, such as natural philosophy, sexual medical advice, sentimental novels, and erotica. 11 It also suggests that thinking about matching implies considering not only the actors who wrote about or worked on the practical implementation of matching techniques but also how contemporaries understood what John Sutton called the "epistemologies of the innards" or Simon Schama referred to as "the long, vexed relationship between the body and the rest of us (soul or mind)" and what consequences these models had for imaging harmonious societies, as they dealt with the forces that attract and pull people apart and the mechanisms to control them. 12 It also suggests how, even in philosophical models that defend the idiosyncrasies of individuals, we can still trace the dream that if enough data is gathered, eventually a system to know the inner self based on external signs could be developed, thus allowing a prediction of sorts. The essay is structured in three parts: first, on the criticism that Feijoo articulated about humoral and mechanical physiologies that naturalized misogynists' views; second, on Feijoo's ideas on the physiology of love; and third, on the applications of his model to a possible epistemology of the match.
Right at the beginning of his Teatro crítico universal, Feijoo launches his "Defense of Women" ("Defensa de las mujeres"), in which he argues for the intellectual equality of the sexes. 13 Feijoo thus fully engaged with a famous philosophical polemic that ran through the entire early modern period, the querelle des femmes, or debates about the equality of the sexes. 14 To be sure, most of his arguments were not brand new; they had a long tradition and had already been used by seventeenth-century female writers, such as Marie de Gournay, Lucrezia Marinella, and María de Zayas; by followers of Cartesian ideas who defended the independence of mind from its bodily substrate; and by important figures in Parisian polite society. 15 Furthermore, the fact that Feijoo convincingly defended the intellectual equality of women does not mean that he himself was free of misogynist bias in other ways. 16 However, he consistently demonstrated that there were no physical reasons justifying differences between the intellectual faculties of men and women. This is particularly clear in the criticism Feijoo articulated about other medical models-for instance, that of the famous Spanish physician Juan Huarte de San Juan (ca. 1529-ca. 1588), whose work enjoyed a renaissance in 1702 with a new edition of his Examen de ingenios para las ciencias (1575). The point of the Examen was to explain from a humoral standpoint how and why different temperaments were suited for different intellectual pursuits. Huarte even offered advice on how to choose spouses according to the characteristics that one hoped for in one's progeny. He graded intellects on a scale that ran from the driest and hottest male mind to the moistest and coldest female mind, the latter the most unsuited for thinking. These qualities of their sex, Huarte argued, made it impossible that women might be "endowed with any profound judgment." 17 Feijoo mocked not only the system of Huarte, but also that of Nicolas Malebranche, who attributed the causes of women's diminished intellectual capacity to the greater "tenderness" (molicie, blandura) of their fibers. Leaving aside the fact, stated Feijoo, that no anatomist was really able to prove whether this was the case, why should a softer brain be less capable of reasoning? He 13 B. J. Feijoo, "Defensa de las mujeres," in Teatro crítica universal, Vol. 1, pp. 325-398. On the responses to the "Defense" see Mónica Bolufer Peruga, "'Neither Male, nor Female': Rational Equality in the Early Spanish Enlightenment," in Women, Gender, and Enlightenment, ed. Sarah Knott and Barbara Taylor (London: Palgrave Macmillan, 2005), pp. 389-409. 14 Armel Dubois-Nayt, Marie-Elisabeth Henneau, and Rotraud von Kulessa, Revisiter la "querelle des femmes": Discours sur l'egalité/inégalité des sexes en Europe, de 1400 aux lendemains de la Révolution (Saint-Étienne: Publications Univ. Saint-Étienne, 2015). See also Mónica Bolufer and Montserrat Cabré, "La querelle des femmes en Espagne: Bilan sur l'histoire d'un débat," ibid., pp. 31-45. 15  But what I feel is that with such philosophical discourses everything can be proved, and nothing is proved. Every man philosophizes in his own way: and if I were to write for flattery, or for caprice, or for ostentation of wit, it would be easy for me, by weaving consequences out of admitted principles, to raise the understanding of women miles above that of our own. . . . We are all blind, and the blindest of all is the one who thinks he sees things clearly. 18 As a counterargument to these male philosophers, Feijoo turned to Oliva de Sabuco, author of the Nueva filosofía de la naturaleza del hombre (1587), which had recently been republished. 19 The Nueva filosofía was at odds with Galenic medicine. Rather than explaining sickness as an imbalance of the four humors, Sabuco gave a preeminent role to a nervous fluid that she believed was equally produced in male and female bodies. Sabuco aimed to develop a novel understanding of bodies that did not suppose "dryness" as a necessary quality for elaborating thoughts. On the contrary, she argued, it was the "moistness" of the brain that was more important.
To be sure, Feijoo's recognition of Sabuco had patriotic overtones. Feijoo claimed that Sabuco's system had been copied by English doctors of the Thomas Willis circle. More important, his praise of Sabuco showed that alternative medical ideas could be defended, that they were not necessarily opposed to Catholic dogma. For Feijoo, defending the equality of the sexes was not only an issue of fairness: it assured social harmony in accordance with Catholicism. Only if women recognized that their reason weighed as much as men's would they be able to fight off men's sexual assaults outside of wedlock; only if husbands valued their wives would they be able to avoid infidelity, engage in lasting, congenial unions, and love women "as God orders." 20 Yet in showing that there were no scientific reasons justifying sexual differences in mental and moral capacities, Feijoo also showed that there could not be any differences in men's and women's ways of feeling and desiring, in their appetites and passions. Love could arise with equal strength in male and female bodies. The intensity of amorous feelings was not a mark of femininity. Feijoo, for instance, heartily disagreed with the common opinion that statesmen and military men should not be of an "amorous nature" because that was a symptom of "childish and effeminate spirits." On the contrary, he argued, people capable of feeling love deeply often have the qualities needed by statesmen. They are often "sweet, benign, kind, obliging, human, liberal, deferential, and caring." 21

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More specifically, Feijoo distinguished three classes of love. The first, "pure appetite," was what one felt, for instance, when smelling a delicious fruit. These tantalizing objects provoked "appetite" because the soul had already experienced them and could thus evoke a "representation of the pleasure." In the second class, "intellectual love," only the rational soul was excited, an example being 18 Feijoo, "Defensa de las mujeres" (cit. n. 13), pp. 366, 367-368. 19 Martín Martínez, "Elogio de la Obra de nuestra insigne Doctriz doña Oliva de Sabuco," in Nueva filosofía de la naturaleza del hombre (Madrid: Imp. Domingo Fernández, 1728). There is some debate today about whether this text was written by Oliva de Sabuco, by her father, or by both of them. See Álvar Martínez-Vidal "Los orígenes del mito de Oliva Sabuco en los albores de la Ilustración," Al-Basit, Dec. 1987, 13:137-151;and Pomata, "Introduction" (cit. n. 8). 20 Feijoo, "Defensa de las mujeres" (cit. n. 13), p. 392. On the possibility that Sabuco was in fact known and influential in the English circle of Thomas Willis see Pomata, "Introduction," pp. 74-84. 21 Feijoo, "Causas del amor" (cit. n. 1), p. 378. the love that one feels for God. Finally, there was "pathetic love" or the "passion of love," the one that most interested Feijoo. 22 At the origin of love was the question of how one first perceived and sensed the other.
Dealing with the origins of love required that Feijoo deal with the thorny mind/soul-body problem-namely, how matter is capable of producing immaterial entities such as sensations, thoughts, and feelings. As is well known, the post-Cartesian, post-Lockean context of the time was awash with debates on how to conceive the relationship between soul and body, which could (and did) slip into materialism, fatalism, and atheism. 23 Although some of his contemporaries postulated the existence of material souls, Feijoo strongly supported an immaterial soul as the ultimate cause of sensations, believing that acceptance of the view that complex operations could be performed only by matter risked atheism. The connection between the soul, the senses, and the organs was believed to be mediated through the nerves. Most contemporaneous models-for instance, that of Thomas Willis (1621-1675)-pictured nerves as hollow tubes through which animal spirits (extremely subtle, easily disturbed fluids) traveled quickly, provoking organic responses. However, for Feijoo, nerves were solid, similar to the cords of string instruments, which exercise their influence through vibrations. His was not a hydraulic model, in which sensations and desires were provoked by animal spirits that agglomerate or flee into or away from different organs, but an undulating one. 24 He nevertheless kept the viscera as the locus of feelings. Just as hunger is felt in the stomach, Feijoo tells his readers, the organ that feels love is the heart. Feijoo was explicit about how "flames of love" influence the heart: "Love disturbs, agitates, compresses, dilates, infuriates, saddens, rejoices, and encourages [the heart] according to the different states in which the lover is." Still, he held, the ultimate origin of these agitations was in the brain rather than in the soul. This is certainly so, Feijoo argued, because amorous feelings are involuntary, while if they originated in the soul they would be voluntary. 25 The model will perhaps be clearer if we examine, through the lens of Feijoo's physiology, what might be happening in Un déjeuner de chasse, a painting by Jean-François de Troy, a contemporary who was interested in representing the sentiments of his sitters through eyes and gestures (see Figures 1 and 2.) The girl's body impresses on the boy's retina; perhaps her delicate smell also impresses on his olfactory sense. Each of these sensations produces different effects in his nerves, as these, according to Feijoo, can "separate, corrugate, stretch, compress, loosen, or become more flexible or more rigid" depending on the stimulus. These nervous agitations reach a particular part of the brain, the "sensorio común," and are then transmitted to the soul, where "perception" occurs. In Feijoo's words, "it is the soul that sees, not the eyes." 26 Then the imagination (a part of the soul) agitates the brain, which in response sends, via the spinal nerves, other mechanical movements to the heart and sometimes, if love has a "concupiscent part," to the genitals and the breast. 27 Feijoo also speculated on the influences of chemicals. If the boy had recently eaten or drunk, the salts dissolved in his blood would affect his heart through "occult pores," predisposing him to salacious attraction.
For Feijoo, then, it was ultimately the individual micro-disposition of fibers and pores, identical between the sexes and indistinguishable even with the microscope, that made two people fall in love. He acknowledged the possibility of the existence of different temperaments based on "nervous dispositions": perhaps, he suggested, those who were melancholic felt the movements that come together as sadness more clearly than the undulatory movements for love. 27 On this point Feijoo quoted Willis, who described how the intercostal nerve communicates between the brain, heart, breast, and genitals. With all these variables, predicting whether two people might match before an actual physical encounter took place would be incredibly difficult. This was straightforwardly expressed in a polemical piece that brought Feijoo into conflict with the Inquisition, "Importancia de la ciencia física para la moral." Feijoo addressed himself to confessors and preachers who forbade the faithful from attending balls, comedies, and other places where the sexes mixed. According to Feijoo, there was no sin in attending these events, as it is not the place of their meeting but, rather, the inner nature of individuals that made them more or less susceptible to arousal. As he put it, "concupiscence has much variability." Nor, he argued, were beautiful women more dangerous than the others, as kindness, discretion, and even vices such as arrogance arouse men. 28 And yet, the close commerce between soul and body could allow for prediction of sorts. An epistemology of the match supposed that one could know, by analyzing certain signs (for instance, astronomical charts, skull's geographies, "confessions" that reveal intimate aspirations), of compatibility between certain people. For Feijoo, too, signs existed: one could, upon encountering another-or witnessing such an encounter-analyze "gestures." 28 B. J. Feijoo, "Importancia de la ciencia física para la moral," in Teatro crítico universal, Vol. 8 (1739), pp. 341-389, esp. pp. 375-379. F O C U S Figure 2. A schematic representation of the physiology of love according to Feijoo. The well-known representation of the brain and the diagram of the sympathetic nerves were engraved by Christopher Wren for Thomas Willis, The Anatomy of the Brain and Nerves (1664). The first one is viewed from below and shows the connections with the cranial nerves; the second one shows the beginning of the spinal nerves. Copyright: T. Willis, Cerebri anatome, Wellcome Collection. Attribution 4.0 International (CC BY 4.0); and T. Willis, Dr Willis's practice of physick, being the whole works of that renowned and famous physician, https://archive.org/details/BIUSante_00238.

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As a consequence of his physiological model of the passions, Feijoo admitted the possibility of discerning some "inner truths" from external signs, what he called a "new physiognomic art." Since the soul communicates with the body directly through the nerves, it effectively and continuously provokes "subtle and delicate movements" of the flesh. The moral disposition and feelings of others would thus be apparent by observing not their static traits but their movements, "the air, their gestures" (gesto). Feijoo gave the well-known examples that shame flushes the face, happiness makes the eyes spark, and anger incites fiery gestures. However, he distanced himself from Renaissance physiognomy, mocking, for instance, Giambattista della Porta and his comparison of humans and beasts and fixation on individual anatomical traits. 29 Feijoo also refused the classical idea that paired goodness and physical beauty. 30 This certainly echoed the times. 31 Physiognomy's assumptions, methods, and modes of description were changing, and contemporaries were reconceiving the workings of the face and bodily movements. 32 Important for the question of matching is that Feijoo recognized a "natural" capacity in most humans for interpreting the gestures of others. The effect of inner passions was especially visible in the eyes: "All the mutations of the soul [are] reflected in the sparkling eyes, the wandering eyes, or the restless eyes." 33 An insightful observer, Feijoo argued, with a rich social life and plenty of time, might eventually go beyond natural body language and learn to pair signs with meanings. In theory, it would thus be possible for a trained observer to predict whether two people would get along and form an amorous bond just by observing their gestures-the enlargement of pupils, the nervous stroking of the hair, the inclination of heads.
The mechanism that explained how amorous attraction arose also suggested ways of governing the course of one's passions. Since antiquity, doctors had recognized that unrequited love was a threat to health and had advised various remedies. Feijoo adapted these cures to his physiological model: the only way to stop the tender undulating waves shaking one's heart was, unsurprisingly, to counteract them with another strong current. The most effective such remedy was to associate the lover's image (that is, his or her representation in the imagination) with a dreadful image that provoked horror. In Feijoo's words: "one wave breaks the impetus of another wave." 34 He detailed practical ways to do this-specifically, which horrible images were to be selected and how to habituate the imagination to switch from one image to the other automatically.
These techniques were necessary because he believed that, even if the will could in principle learn to "suspend the act of loving," it could not be done without "difficulty, or repugnance, making violence onto oneself." 35 In this sense, although Feijoo's physiology precluded techniques of predictive matching, it nonetheless presented strategies for unmatching those with whom one had fallen in love. Furthermore, the possibility remained that this strategy could work in the reverse direction-that is, to arouse amorous feelings voluntarily by training the imagination to associate rapture and joy with the representation of the person with whom one would like to fall in love. While love's initial stirrings could not be known in advance, physiological knowledge might grant lovers agentive control thereafter.

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In Feijoo's physiology of passions, one falls in love when another literally makes one's heart tremble. The common agitations of two sensible hearts then make a match. Matching rules are thus difficult, if not impossible, to formulate. A vast number of individual variables, material and spiritual, permanent and temporary, are continually and contingently interacting: the undulating fibers of the nerves, heart, and brain; the images created in the imagination; and the memories that interfere with these images. The old classification of temperaments is of no use in guessing who will be one's sweetheart. Possible matches cannot even be selected by looking at static portraits, as the soul is incessantly modifying the flesh. Beauty, both internal and external, is expressed in gestures-in movement, not in still pictures. It might be possible for one to train oneself in the art of observing these subtle facial and gestural reactions, the better to discern the nuances that betray attraction. It might be possible to habituate the nerves to rid oneself of love unwanted or to produce love where previously unfelt. But only after actual in-person encounters can these techniques be put into practice. There are no guidelines, before bodies meet, for predicting the right match. 35 Feijoo, "Remedios del amor," p. 385.