The cosmopolitan climate of the 16th century ([26]; [7]; [18]) owed a great deal to the intersection of cultures in Western Europe up to that date, namely, those cultures that emerged from the fall of the eastern Roman Empire and the subsequent westward migration of Byzantine artists and intellectuals; the novelty inherent in the discovery of a new world through the then-recent circumnavigation of the planet, and the finding of new zoological and botanical specimens, new territories, and novel human cultures unimaginable until then; which at once challenged both the work of medieval cartographers and the prevalent model of common sense. In effect, sense knowledge earned the spotlight because it is through the senses that one apprehends the external world, and the accumulation of successive experiences produces new scientific discoveries, leads to uncharted territories, and helps navigate the oceans, the foibles of the human sensorium notwithstanding.

Out of the meeting of East and West, as the Turks occupied Constantinople, the arts and sciences flourished. New bodies of work by ancient and contemporary authors, mostly in Greek, came to enrich libraries. The same can be said of the encounters between intellectuals, namely, authors and translators. The advent of the printing press helped disseminate the written word, divulging thousands of works on an unprecedented scale, revolutionizing the intellectual landscape. ([25]) Natural philosophy gained new momentum. The study of the human body was refined, thanks above all to the far-ranging dissemination of the work of doctors such as Hippocrates, Galen, Vesalius, and others. Pliny and the ancient naturalists offered renewed contributions in dialogue with the naturalists of the time. This globalization would drive a conversation between the old and the new, turning ancient thinkers into contemporaries, after a fashion.

Aristotle would be read with renewed interest, whether it be his works on natural philosophy or others, namely, on psychology. The Middle Ages had already deemed the study of the soul a crucial element in the understanding of life in general and human life in particular. In the 16^th century, matters of religious disputation among Christians deepened the study of the rational soul, specifically the so-called separate souls. Commentaries on Aristotle from schools and universities proliferated. The Treatise on the Soul, for the reasons we have laid out, rose in popularity among scholars, who would approach it not only from a naturalist perspective but also manifest a keen interest in the adventures of the human intellect and the rational soul.

Attempts to separate philosophy from theology would persist. Such was the case with Pomponazzi, who would indirectly call into question the maxim that philosophy is ancilla teologiae ([2]; [23]). However, the role of experience arising from sense knowledge would be crucial—it establishes natural philosophy as the mandatory starting point for all other forms of knowledge.

The development of physics during the Renaissance had close antecedents in the Middle Ages, in universities, more specifically in schools of the arts. Empirical approaches to natural phenomena and the valuation of experience would evolve throughout the Middle Ages, especially from the 13^th century onward. Franciscans and Dominicans, who held the leading cathedras at universities, played a prominent role in this domain. Additionally, the circulation of Greek texts in universities, works mostly purveyed by Arabs, and the Latin translations of said texts spread the names of authors essential to the development of Natural Philosophy: Aristotle, Euclid, Galen, Archimedes, Ptolemy, Pliny, and others. Naturalists would then explain nature based on the science in these texts and on inquiries pursued by Arab and medieval researchers. Several authors and works were divulged—the Neoplatonists, Ptolemy’s Geography, Lucretius’ De Rerum Natura, Celsus’ De Medicina, Galen, Pliny, as well as Pythagorean, hermetic, and kabbalistic texts, such as the Corpus Hermeticum, attributed to a supposedly historical author ([27]).¹ The work of Pico della Mirandola also traveled from scholar to scholar. Among other efforts, Pico della Mirandola intended to reconcile magic and Natural Philosophy ([16]).² There is a yearning to explain nature and the world from intrinsic causes. Paradoxically, this arose from a crisis of faith in human knowledge, a crisis that helped bring about the climate of doubt and existential unrest of the time, and persisted until the beginning of modernity. While medieval scholasticism assumed the existence of rational order in nature, affirming that the human intellect could peer into that order, as it formed a part of it, upon contact with all the novelties ushered in by the Renaissance, and learning, through experience, that there was a difference between the universe as described until then and the new, inchoate image of it, doubt and uncertainty arose. The more perfected the mechanisms and devices available, namely in the field of optics, the greater the distrust in the ability to understand the world, as it was found that the senses, more specifically the sense of sight, were limited, and new horizons were unveiled that surpassed the ordinary capabilities of human vision. Here lies the paradox of the times: on the one hand, the external world can only be apprehended by the senses through experience; on the other hand, the senses are fallible. Many, as we have mentioned, seek refuge in attempts to unveil an occult mathematics of nature, looking for a secret meaning within it, for reprieve in esoteric, alchemical, or Kabbalistic explanations. Man becomes a demiurge, interrogating nature, the universe, and himself, sifting through the relevant correspondences for the construction of the occult meaning that the senses can no longer fully supply. The uncertainty over the validity of the paradigm accepted as perfect until then was a source of disillusionment, melancholy, and distrust in human ability. Therefore, on the one hand, the senses are the gateway to knowledge and the only means of accessing the world; on the other hand, knowledge derived from the senses isn’t deemed wholly reliable. Difficulties in building up a new cultural paradigm caused the resurfacing of skeptical movements ([15]; [17]).³

The invention of the printing press democratized knowledge and spread it far and wide; economic development brought about improvements in science and technology, and persistent experimental efforts opened Pandora’s box of curiosity and nurtured the Promethean myth that drives modern man. Knowledge was widely disseminated regarding the construction of astrolabes, compasses, microscopes, telescopes, thermometers, and other instruments that would supplement the acuity of human sight, extend the reach of other senses, and stimulate human action on nature, like a prosthetic addition to the external senses, which would unleash a flood of new discoveries. The crumbling of the ancient universe as new territories were unveiled and a new perspective on nature arose, through the use of instruments that would pierce through to its core, revealing new constants that led to the articulation of laws, also led to a human belief in the creation of new worlds, a belief embodied in the many utopias of predominantly Neoplatonist inspiration that emerged.⁴ No knowledge, specifically intellectual knowledge, can be attained without the experience that originates in natural philosophy.

Today, it is a given that the scientific impetus among the Portuguese Jesuits of the time kept up with the pace of development across all of Europe, contrary to a few claims ([11]).

Lisbon is known to have been a hub of cultural exchange with the Far East. This level of scientific development extended to the rest of the country, as manuscripts and ideas flowed among the schools in Lisbon, Coimbra, and Évora. Fr. Christopher Clavius (1538-1612), a brilliant mathematician and cosmographer, close to Galileo, remained in Portugal during the second half of the 16th century. Matteo Ricci (1552-1610), who studied under him in Portugal, shipped out to the East, where he played a key role in the so-called Court of Mathematics, an imperial body of the highest prestige, where the calendar was set, eclipses predicted, and astronomical observations conducted. The Jesuits out of Lisbon enjoyed renown and acceptance in the Far East thanks to their knowledge of mathematics. Scientific education took place in schools and aboard ships during long sea voyages, the regular stop in Goa notwithstanding ([9]).

The dissemination of mathematics and astronomy in the East was essentially the work of Jesuits and the Catholic West’s (as well as the Pope’s) calling card in the region ([4]; [5]). The Society of Jesus’ research and development of mathematics applied to technological knowledge, manifestly surpassing the kind of teaching purveyed by the medieval quadrivium, represented a factor in the embrace and acceptance of Jesuits by other civilizations—in this case, those of the Far East ([8]; [19]; [22]; [14]). Wallace points to the direct influence of educational material used by the Jesuits in Galileo’s early scientific works. He based his thesis on the reading of materials used in the Roman College ([28]).

Comparing the manuscripts of the Roman College at the Biblioteca Nacional de Lisboa [National Library in Lisbon] with those in Évora and Coimbra, along with the respective annotations, the researcher found that the materials used for Physics and Mathematics accompanied Galileo’s first steps in science, demonstrating that Jesuit education in 1580s Portugal did not greatly differ from that dispensed at the Roman College. As to the Coimbra Course, however, the author mentions that the subjects in its several volumes, products of the typical research of their time, did not give greater preference to the study of sciences and mathematics, valuing—deliberately, to all appearances—the discussion of theological matters ([22]; [13]; [12]; [6].[6]; [21]). In fact, the Jesuit College of Coimbra (Colégio de Jesus de Coimbra, CJC) in the 16^th century was committed to training good theologians, priests who were tasked with saving souls. Although they did not make the study of mathematics as prominent as the Roman College had, we should point out the importance of natural philosophy, as CJC missionaries would be sent to distant lands. Hence, the attention to biology, geography, and atmospheric phenomena.

As we stated above, the development of sense knowledge drove the changes that took place in the late Middle Ages. More precisely, experience became an instrument for the deconstruction of a picture of the world inherited from tradition. The senses would channel a new picture, establishing a recognized, credible way to access knowledge. The late Middle Ages faced a challenge not unlike the one at the start of the era: an attempt to reconcile tradition with the novelties of the time. Changes in worldview caused by novelty, much of it arising from the discovery of new lands and the disintegration of geocentrism, strongly impacted people then. If we add the abundant flow of written information afforded by the printing press, we may state that it would not have been easy to build a renewed cultural identity. This tropism is largely expressed in the Jesuit Course of Coimbra when it comes to valuing experience. So, the role of seafaring and the Discoveries is often invoked to defeat arguments based on ancient authorities, weaving a new reading of nature. Examples of that would be:

—that ocean water fills chasms on land;⁵

—that America is added to the parts of the Earth, and it follows that Brazil is added to America;⁶

—that day and night are of equal length on the Equator, and the climate is explained through the facts observed in the region;⁷

—invoking knowledge gleaned from seafaring to demonstrate the existence of the antipodes;⁸

—indicating facts transpired in “our century” as causes of flooding, in this case, abundant rainfall;⁹

—how the moon influences ocean tides;¹⁰

—that the color of the Red Sea can be explained by the corals at the bottom.¹¹

The admiration for, and attention paid to, the Discoveries by the Coimbra Course is evident:

Experience is the mother of philosophy;thus, the thingsthat fall under thesenses must not be studied by mathematical and metaphysical means,but through resort to experience aided by the senses.¹²

On this matter, Banha de Andrade: So that the scientists of the ocean(Duarte Pacheco Pereira and D.João de Castro)or the scientists who weren’t sailors(Garcia de Orta and Pedro Nunes),and the philosophers(like the ones from Coimbra),they all found brotherhood in the same spirit of revolution. They all held antiquated and even more metaphysical than experimental positions when experiencehad nothing to offer.But,whenever experience spoke(and let us admit that its powers of speech were limited then),everyone at once paid attention. ([10])

The valuation of experience from the senses does not mean the experiments in so-called modern science ([24]), but what Luís Filipe Barreto termed experientialism: “A scientific-philosophical theory starting from,and about,the concept of experience (...),a creation exclusive to the domain of true knowledge,the universe of scientific theory and practice in the culture of expansion.” ([3]; [1])

The importance of external senses as intermediate portals between the outside world and the intellect is reinforced through education. DA is an example of that. While the trajectory of most students in Jesuit colleges was to study theology and become priests or missionaries, channeling the perspective of education through the message that the ends of human action revolve around God and otherworldly salvation, the relationship with the world as it presented itself at the time called for the deepening of science in general to allow the possibility of intervention in a society targeted by radical change, change which offered re-readings of nature and its own norms. Let us not forget that the preparation of missionaries for Brazil, India, and the Far East entailed solid training in Natural Philosophy to inform their mission among foreign peoples in distant lands. There was deep concern with the study of the sensitive soul and the rational soul, namely, in their mutual relationship. So DA devotes most of its pages to the study of sense knowledge.

Regarding experience, it is of interest to mention how it appears throughout the most varied debates. Following arguments from authority, doctrinal ones intended to ground a given stance, experience is invoked as a credible means of proof and often as a tiebreaker, appearing as a judgment of authority side by side with traditional authorities. This experience is derived from common-sense knowledge. As the soul is attached to the body, resorting to experience becomes indispensable to learning and developing judgment. The rational soul receives from the senses what information the intellect requires. Without experience, intellect does not work. Experience, therefore, comes into a fundamental epistemological status.

Here are some examples drawn at random from among the many extant in the treatise:

Certainly,if a very strong sense datum were to impress upon the sense the species with so much efficacy as to preserve it,even in its absence,that would happen always,or most of the time. But this contradicts experience. Hence, Aristotle,in this book,chapter5,texts52and59,establishes the difference between sense and intellect because the former demands the presence of the object,but the latter does not.¹³

One can easily explain the arguments that sought to prove that the external sense in some way falls into error. To the first,one replies that there can be no human science if the senses make nothing known,but permanently elude the acuity of the mind. The facts differ greatly. Ordinarily, the senses do not err. Although they sometimes make mistakes,experience born of the conjunction of many mutually concurrent sensations is notdestroyed,andgreatly contributes to the ascertaining of first principles.¹⁴

Third,because,if light were embodied,it would move in place,and so illumination would not happen in an instant,but in time,which experience abhors,aswe see that light travels immediately and without delay from one place to the next.¹⁵

This also happens when things are greater and therefore can be seen from a more distant place,so that,at any point,or any part of the medium illuminated in the act,the whole body as an object is represented in the sense organ,and also each one of its parts,from which one can draw a straight line toward a point or part of the medium,in such a way that in any part of the medium its likeness is impressed by any part of the colored object.This is what experience confirms.¹⁶

In truth,for all its parts to produce the likeness,they would need a space of a magnitude as vast as the Sun itself,which experience abhors,as we observe the Sun from any point in the medium. Soit is necessary that all the parts of the visibleobject find their likeness in any part of the medium in which they are represented.¹⁷

But this position is refuted because,if vision were made there,it would follow that the men in whom those nerves do not in any way connect(it is said such cases were found)would either lack vision altogether or,as the defenders of the contrary position uphold,would see all things doubled,which experience has proven to be false.¹⁸

No doubt there are men who see the waters latent in the soil. But they are driven,as is opined,not so much by philosophical reasons as by experience.¹⁹

Those who distinguish it from refrigeration therefore say that ventilation is the coaxing and ascension,above all,of heat in motion,as heat is triggered by movement,as experience shows,and we convey with Aristotle in the second book On the Heavens,chapter seven,question the sixth. Thirdly,to form the voice,a function that is expressed in the definition of voice.²⁰

On the contrary,many odors are unpleasant and noisome,as experience makes evident. Strabo recalls in book16 that the Sabeans would sometimes be numbed by odors.²¹

Because,if the intelligible species existed in the intellect,given that these are considered natural causes of intellections,any given intellect could not stop using them and would find itself permanently occupied with understanding the things that are represented through them,which experience abhors.²²

It is precisely about admiration that Manuel de Góis broaches one of the key points relative to experience. Experience is a source of novelty and admiration, offering unique knowledge.

To prove it, when he debates the novelty of admiration, he takes Jesus Christ as an example.

One may object,however,that it does not appear that the object of admiration is correctly presented as something new and unheard of,because in Christ,our Savior,there was admiration; in fact,as stated in Matthew,chapter 7,he admired the centurion’s faith,and,however,nothing new and strange could happen to Christ.

To this objection,one must answer that,although for Christ,according to the different modes of science in his possession,nothing new could exist,it might,however,exist through experiential science,through which He would compare against experience what He already knew in other ways. And in such a way there was admiration in Him. Christ took on that affection above all to indicate that we must admire,because He too admired,as Saint Thomas recorded, 3^rdpart of the Summa Theologica,Question15,article8,from Augustine,book1 on the Genesis Against the Manichaeans.²³