In section 1.3.3 we alluded to Alsted’s notion according to which, with respect to the encyclopedia, individuals are like so many containers, each capable of holding a content commensurate with his or her receptive capacity, and none capable of containing in themselves the whole sum of knowledge. In any kind of communicative interaction, it is clearly necessary to presuppose and infer the format of the individual encyclopedia of the persons speaking to us, otherwise we would attribute to them intentions (and knowledge) that they do not have. This is basically why we so frequently bring into play the principle of charity. But as a rule (except when we are dealing with anomalous interlocutors such as a child, a foreigner from a remote and unknown culture, or a mentally challenged individual) out of considerations of economy we have recourse to what we consider to be a Median Encyclopedia. Though its extent is difficult to measure, a Median Encyclopedia is identified with the contents of a given culture.
So, just as knowledge of the works of Plato (except for the Timaeus) were not part of the Median Encyclopedia of medieval culture, in which notions about Plato came from Neo-Platonic sources, in the same way part of our current Western encyclopedia is the idea that the Ptolemaic system was believed to be true in the past whereas today it is considered erroneous (without its having been forgotten). To sum up, we might say that the Median Encyclopedia is represented by an encyclopedia in the publisher’s sense of the word—and probably a mid-sized one-volume encyclopedia and not the thirty-two volumes of the 2010 Britannica.39
The fact that it is a Median Encyclopedia does not mean that all of its contents are shared by all members of a given culture, but rather that it is shareable (we will examine in more detail later, in section 1.9.5, the concept of “latency” of information). Even an educated person may have forgotten (or never have known) the date of Napoleon’s death, but that person knows that the information is accessible and usually knows where to find it. This is why it is said that a cultivated person is not someone who knows the dates of the beginning and the end of the Seven Years War, but someone who can come up with them in a couple of minutes.
The Median Encyclopedia cannot be identified with an extensive library containing thousands, even millions of volumes, because such a library, though it may not be commensurate with the Maximal Encyclopedia, nevertheless encompasses the Median Encyclopedias of exotic cultures, of past civilizations, and ideally all of the Specialized Encyclopedias, past and present. That library is instead merely an attempt to approximate the Maximal Encyclopedia, fatally incomplete because the Maximal Encyclopedia does not contain only those ideas that have been committed to the written word.
The fact that, not just the Maximal Encyclopedia, but even the “parody” of it represented by a normal library should provoke the vertigo of a knowledge so exaggeratedly extensive that nobody could ever capture or contain it in their own individual memories, leads us to the problem of memory and forgetfulness; the problem, in other words, of the Vertigo of the Labyrinth.
1.9.2. The Vertigo of the Labyrinth and the Ars Oblivionalis
Since classical antiquity, the problem of the need to forget appears contemporaneously with the development of mnemonic techniques by which to commit to memory the maximum possible amount of information (especially in the centuries in which information was not as readily obtainable and transportable as it has since become, with the invention first of printing and subsequently of electronic devices). In De oratore (II, 74), for example, Cicero cites the case of Themistocles, who was gifted with an extraordinary memory. When someone offered to teach him an ars memorandi, Themistocles replied that his interlocutor would be doing him a greater service if he taught him how to forget what he wished to forget than if he taught him how to remember (“gratius sibi illum esse facturum, si se oblivisci quae vellet quam si meminisse docuisset”), inasmuch as he would prefer to be able to forget something he did not wish to remember than to remember everything that he had once heard or seen (“cum quidem ei fuerit optabilius oblivisci posse potius quod meminisse nollet quam quod semel audisset vidissetve meminisse”).
Themistocles’s concern, incidentally, anticipates (and perhaps inspires) the anxiety of Borges’s Funes the Memorious, who remembered each and every detail of his experiences and perceptions, to such an obsessive and unbearable degree, down to the mere rustling of a leaf heard decades earlier, that he was practically unable to think.
The problem of the excess of memory explains why one of the terrors of the practitioners of mnemonics was that of remembering so much as to confound their ideas and forget practically everything as a result. It seems, in fact, that at a certain point in his life Giulio Camillo had to excuse himself for his state of confusion and for the gaps in his memory, citing as an explanation his protracted and frantic application to his theaters of memory. On the other hand, in his polemic against mnemotechnics, Cornelius Agrippa (De vanitate scientiarum) claimed that the mind is rendered obtuse by the memorative art’s resort to “monstrous” images and, being so overburdened, is led to madness. Hence, subterraneously parallel to the fortunes of the ars memoriae, the reappearance from time to time of the phantasm of an ars oblivionalis (see Eco 1987a and Weinrich 1997).
In the twentieth lesson (“Lettione XX”) of the Plutosofia of Filippo Gesualdo (1592), the “methods for oblivion” are reviewed.40 Gesualdo excludes mythical solutions such as drinking the waters of Lethe. He is aware that Johannes Spangerbergius in his Libellus artificiosae memoriae (1570)41 had already reminded his readers that people forget from corruption, that is, from forgetfulness of past species, by diminution (old age and sickness), and from ablation of their cerebral organs. Likewise, it is obvious that we can forget by repression and suppression, drunkenness and drugs, but all these are cases of natural occurrences that must be studied and are studied elsewhere.42
Gesualdo, however, is intent upon developing an art of forgetting that employs the same techniques as an art of remembering,43 and he advises:
First, having recited, and wishing to consign the images to oblivion; either in the daytime with closed eyes or in the dark and quiet of the night, you should go wandering with your mind through all the imagined places, evoking an obscure nocturnal gloom that hides all of them, and proceeding in this fashion, and going back a number of times with the mind and not seeing any images, every figure will soon disappear.
Second, go peering into all the places with the mind, back and forth, and contemplate them empty and bare, as they were formed for the first time without any images in them, and this operation should be performed several times.
Third, if the persons in the places are persistent, let them be seen by the mind from all angles many times, and let them be contemplated in the same way they were first set up, with bowed heads and dangling arms, without any additional images.
Fourth, just as the painter pastes over and whitewashes his paintings to cancel them, so we too can cancel the images with colors painted over them. And these colors are white, green or black; imagining over the places white curtains, green sheets or black cloths; and going over the places a number of times with these veils of colors. And one can also imagine the places stuffed with straw, hay, firewood, merchandise, etc.
Fifth, I consider it an excellent rule to put in place new figures; because just as one nail drives out another, so forming new images and putting them in the places already imagined, cancels the first images from our memory. It is true that it is necessary to imprint them with great care and mental effort and to repeat them frequently in the dark and quiet of the night, so that the intense and vivid idea of the second ones drives out the first Ideas.
Sixth, imagine a great storm of winds, hail, dust, ruined buildings and places and temples, a flood that leaves everything in a state of confusion. And when this noxious thought has continued for a while and been repeated several times, finally go walking among the places with your mind, imagining the weather bright and calm and peaceful, and seeing the places empty and bare as they were formed for the first time.
Seventh, after the longest period of time possible, imagine an Enemy, terrible
