In view of the evidence adduced from passages such as those of Duarte Pacheco Pereira, and above all Garcia de Orta and D. João de Castro, it will be difficult to deny that the primordial importance of the experience was recovered during the period of the discoveries, quite a bit earlier than what is normally suggested for this vital change. But what importance does this have from a historical point of view, if it was no more than an isolated occurrence with no visible repercussion on the evolution of European medieval thought to modern thinking?

I cannot let the opportunity go by of highlighting the fact that it is curious how professionals of a subject that instituted the facts like the foundation stone of any generalising building or construction behave like the practitioners of the other professions, defending the vision received against change when it comes to changing concepts that have for long been crystallised. I imagined that all that would be necessary would be the bringing forward of a date in order for a historian to hurry in correcting compendiums and encyclopaedias, enthusiastically announcing the discovery of a priority.

Enter Francisco Sanches.

Practically everything has been said on the philosopher born in Braga or in Tuy [1] (I will avoid the debate as it is of absolutely no interest to the question at hand) and long before Richard Popkin “discovered” and incorporated it in the Anglo-American narrative of scepticism [2] (Popkin states that Quod Nihil Scitur can be read almost like a text of analytical philosophy of the twenty-first century XX [3]). Among the Portuguese authors who concerned themselves with the work of Francisco Sanches, it would be unfair not to mention Artur Moreira de Sá, who dedicated a study in two volumes, Francisco Sanches, filósofo e matemático [4], to him. Lúcio Craveiro da Silva is the author of a valued summary, written in 1951, on the dual attitude of Sanches in relation to knowledge. On the one hand, the doubt regarding the knowledge received, especially from the decadent scholasticism; on the other, the attitude of trust in relation to the future of science and of its new method [5]. Nothing better, however, than a direct contact with the text in order for us to fully understand how Francisco Sanches’ scepticism is not pyrrhic. Lúcio Craveiro da Silva summed up this difference very well:

Francisco Sanches does not in fact start questioning, as sceptics do, the existence of oneself, of other men, of the world, nor does he state the omnimodous incapacity of the human mind to discover the truth. He does not doubt he order of existence; he never doubts the existence of the adversary nor of the I, but rather that of the science of the adversary and of the I. [6] .

His is a modern position of refusing to recognise the importance of the crucial role of experience and judgement in establishing the truth and of the consequent difficulties in achieving ultimate or definitive truths for lack of infallible criteria:

Why should I not doubt if I cannot understand and get to know the nature of things? This is what the real science should be. It is easy, really, to see the magnet; but what is it in fact? Why does it attract iron? This is what I would like to know, if it were possible to do so. [7]

Sanches is convinced that he is proposing new paths. A believer, he knows that only God, creator of the world, knows what he created. We human beings have to look carefully at nature, to experience it and to use reason to discern it as far as possible. As a nominalist, unsatisfied with truths that are deduced from Aristotelian syllogism, he rejects them as they do not allow us to get to what is important: nature. Sanches writes:

I therefore turned to myself; and doubting everything, as if nothing had been said until then, I started examining the things themselves: this is the true form of knowing. [8]

Let it sound like Descartes and like his methodical doubt; I shall not be the first to point him out. It has already been said that Descartes knew Quod Nihil Scitur and although he wrote his Discourse on Method many years later, he was much more contained and careful in criticising scholastic knowledge and Aristotelism in particular. The connection between Sanches and modernity has thus been established. In the best Oxfordian tradition of Roger Bacon, Robert Grosseteste and William of Ockam, Francisco Sanches is a bridge between them and Locke and Hume. It will not be an exaggeration to say that Sanches is one of the forefathers of the new mentality in relation to nature, to the new science. Quod Nihil Scitur is a lampoon against the anchylosis of traditional knowledge in the cul-de-sac of authority and knowledge based on universals for which undemonstrable uselessness is deduced. Sanches even goes so far as to state the impossibility of having certainties because our knowledge of the truth is in a continuous flow. In Sanches’ words:

If we remove that which exists in us, or which originates from us, from any form of understanding (cognitio), the most trustworthy is that which occurs in the midst of our senses, and the least trustworthy is that which occurs as a result of argumentation. Because the latter is not really understanding, but a mere hunch, a doubt, a supposition and conjecture. Hence, once again it follows that scientific knowledge (scientia) is not what is gained by syllogism and by divisions and categories and other mental operations of a similar kind; yet if it were possible that, in the same way that we understand the external qualities of things somehow by means of our senses, then we could truthfully say that we know. As far as I know, however, no one has even been capable of this. Therefore, we know nothing.

Still along the lines of the type of understanding that has to do with things inside us, and of another kind, which I call not “understanding” but “opinion”, and which results from conjectures, denials, comparisons, divisions and other mental operations, I will deal with this at an appropriate moment, where the lack of knowledge, inherent in both cases, becomes clear. [9]

For this reason, at the end of the work, he recommends:

It is therefore in the interest of our young man that if he wishes to learn something, he needs to study continuously, to read what was written by each author and to compare this information experimentally with facts until the end of his days. [10]

Now all that is needed is to establish how the discoveries contributed to the shock suffered by Sanches in his certainties. Sanches is quite clear on the subject. After listing the enormous variety of human beings, of every kind imaginable, described in so many books or narrated by a large number of observers, he adds:

How can anyone be absolutely certain about what was or what will be? Yesterday, you said in the light of your entire knowledge, or better yet, knowledge which had been complete for years, that all the earth was surrounded by ocean; and you divided it into three large parts – Asia, Africa and Europe. But what will you say today? A new world was discovered – new realities – in New Spain or in the Western and Eastern Indias. And even more, you used to say that the area south of the equator was uninhabitable due to the heat, and that in the area surrounding the poles, and the poles themselves, the same happened because of the heat. Experience has shown us that both of these certainties were proven to be false. Construct another science because your first science is now false. Therefore, how can you uphold that your statements are eternally valid, incorruptible, infallible and incapable of being otherwise – you miserable worm, you that hardly know and are hardly capable of knowing, what you are and where you come from or even where you are heading? [11]

Francisco Sanches may not have known Duarte Pacheco Pereira’s Esmeraldo de Situ Orbis directly, yet he let himself become totally enveloped by the spirit that is set forth in these pages, becoming a leitmotiv in subsequent decades and in the years in which the philosopher’s spirit is formed. Let us compare this passage with one from Esmeraldo:

Never could our predecessors, or even those much older from other strange generations, believe that a time would come when our west was known to the east and to India as it is today, because writers who spoke of those parts, wrote such fables that others were convinced it was impossible to navigate there.

Tolomeu writes, on the painting of his old cosmography tables, that the Indian sea was like a lagoon separated by a vast amount of space from our western sea ocean that runs past meridional Ethiopia; and that between the two seas was an edge of land that prevented anyone from passing to the inside, to that Indian water lily;

(...) Pompónio Mela, at the beginning of his second book and also in the middle of the third one De Situ Orbis, and Mestre João de Sacrobosco, Ingrês, excellent author, on the art of astronomy, at the end of the third chapter of his Tratado da Esfera, both of these authors, each one in turn, stated that the parts of the equinoctial were uninhabitable due to the extreme heat of the sun; whereupon it seems that, according to his theory, this torrid area was unnavigable for this very reason, as the intensity of the sun prevented people from settling there; yet all of this is false; we are certainly right in becoming amazed that such excellent men, as these were, as was Plinio and other authors who stated the same, fell into so big an error as in this case, as they all confess that India is truly oriental and populated by an infinite number of people; and that the true orient is the circle of the equinoctial that passes through Guinea and through India and as most of it is populated, what they wrote is rarely false; for under this equinoctial there are so many people, as far as is known and practised; and as experience is the mother of all things, through it we discovered the truth radically. [12]

The distance between the two authors is indeed vast and it will not be necessary to point it out. Approximately seventy years stand between us and the accumulation of new knowledge; the period of disenchantment with the classics is over in the face of the enthusiasm with the novelties from the ships that sailed over the sea. Duarte Pacheco Pereira is overwhelmed with excitement of acknowledging the errors of our forefathers and of the new truths discovered by experience, so much so that he has no ulterior motives other than those which experience, the mother of all things, provides. Thirty years later, D. João de Castro was much more careful and conscious of the limitations of experience. He considers unquestionable the fragility of the knowledge supplied by the classics, yet tempers the facts of experience with the intervention of common sense. With Francisco Sanches, however, there is a profound reflection on the consequences of this about turn brought about by the discoveries in human knowledge in his crucial question: and who can assure us that the certainties we believe to have now are in fact final? He even sounds like Karl Popper when, after pointing out that no-one ever publishes a definitive book, he calls attention to the fact that if he were able to live for hundreds of years, it would be difficult not to keep adding, subtracting, changing and renovating something. [13]

A radical conscience had been reached of the fragility of human knowledge, of the need to base it on experience and critical judgement. However, this did not suffice in order to supply us with absolute certainties, as it might not take too long for any certainty to be replaced by a new certainty. Hence Sanches’ recommendation to his readers:

I do not promise you entirely the truth, as I do not know it myself, as with anything else: I will, however, search for it as far as I can and once I have found it and driven it out from its hiding places, you shall follow it. Never expect to take possession of it or to keep it consciously: be satisfied with what for me is enough: agitate it. This is my goal; it should be yours as well. [14]

Quod Nihil Scitur ends with the announcement of a new work that would propose a form of freeing oneself of that indecisiveness into which we fall when the metaphysical certainties dessert us and we are limited to analysing nature through fallible experience and judgement. Unfortunately, either Sanches did not ever write this work or else it was lost. Irrespective of his proposal for escaping a situation liable to lead to scepticism or relativism, it does seem as if it could come into conflict with the points of view expressed in Quod Nihil Scitur or in other works of his. It would have been very interesting if we could in fact have had access to Sanches’ proposal to fortify the foundations of knowledge conscious now of its contingency; however, at this point we stopped, at Descartes’ feet, and it would be Descartes who would then radicalise Sanches’ doubt in his own. Modern knowledge will throw itself into the never-ending deepening and fortification of its foundations, in a reproduction of the myth of Sisyphus, in inverted order.

The second edition of Quod Nihil Scitur appeared in Frankfurt in 1618 when Descartes was in this city and it seems obvious in the Discourse on Method that he had read Sanches’ work. [15] In any case, Descartes is not the only door leading to modernity and Sanches’s book was widely disseminated in the Europe of his time.

Another supposed founding father of the scientific spirit is Francis Bacon. And in this regard, Reyer Hooykaas had already taken it upon himself to establish the connection between the discoveries and his new vision [16]. Bacon writes in the Novum Organum:

“...by the distant voyages and travels which have become frequent in our times, many things have been laid open and discovered which may let in new light upon philosophy. And surely it would be disgraceful if, while the regions of the material globe - that is, of the earth, of the sea, and of the stars - have been in our time laid widely open and revealed, the intellectual globe should remain shut up within the narrow limits of old discoveries”. ^[17]

And further on:

And this proficiency in navigation and discovery may plant also great expectations of the further proficiency and augmentation of the sciences". [18]

Hooykaas concludes his essay by stating:

The considerable time lag between the earliest Portuguese oceanic voyages and the work of the early modern seventeenth-century scientists was an incubation period, in which the `new philosophy' had already arisen, albeit almost noiselessly. In 1600, Gilvert published the results of research on magnetism performed in the past (his own experiments included) under the title Phisiologia Nova; and Kepler (1609) called his main work Astronomia Nova. Long before them, however, (1513) a series of `Tabulae Modernae', based on the recent voyages of discovery, was added to Ptolemy’s Geographia by its editor Waldseemuller. The 'geographical revolution' had preceded them by a whole century. Henry the Navigator, who organized the first great voyages of discovery, was no scientist, and he had no scientific aims. But it was his initiative that triggered off a movement which, growing into the avalanche of upheaval in sixteenth-century geography, opened the way for the reform, sooner or later, of all other scientific disciplines. [19]

Luís de Albuquerque reminded us in turn that,

Although Duarte Pacheco Pereira’ work was not published, there is news that at the end of Quinhentos, a copy of it was sent to Spain; there is also news that the treaty of Garcia de Orta was translated into Latin, Italian, French and English, between 1567 and 1604; and finally, let us recall that the magnetic observations recorded by navigators assisted Stevin in drawing up the first, although unsuccessful, attempt to explain terrestrial magnetism. [20]

The lists provided by Hooykaas and Albuquerque can now be supplemented by Francisco Sanches, who between 1574 and 1581, long before Bacon, took the results of the adventure of the discoveries to the last. There are no doubts as to the wide dissemination of his book in the Europe of his time, especially through its second edition in Frankfurt in 1618. Historians continue to raise the question of the impact of the discoveries on modern European thinking; here lies the supposedly lost or, to many, even inexistent link.