By commenting on his annotated edition of the Greek New Testament project from the Vulgate, Erasmus claims in 1515 [Erasmus 1910, 113]:

I have translated the whole New Testament after comparison with the Greek copies, and have added the Greek on the facing pages, so that anyone may easily compare it. I have appended separate annotations in which, partly by argument and partly by the authority of the early Fathers, I show that my emendations are not haphazard alterations, for fear that my changes might not carry conviction and in the hope of preserving the corrected text from further damage (Epist. 337, ll. 862–868; [Krans 2006, 14].

As the exegete Jan Krans explains, the last sentence shows that Erasmus considers a text as remaining vulnerable and corruptible if it is not accompanied by a commentary [Krans 2006, 14]. Erasmus adopts the same attitude in other passages: the text has to be accompanied by comments in order to be read correctly or according to the intended sense. In other words, decades after the invention of printing, Erasmus is still conditioned by the practices of manuscript culture. His opinion reminds one of the famous Platonian passage in the Phaedrus regarding the written discourse that “drifts all over the place [...and is] unable to defend or help itself”; Plato posits that speech is superior to written text, since the former is: “written with intelligence in the mind of the learner” (Plato, Phaedrus 275e and 276a, [Yunis 2003, 208]). A long time before the “factishes” of the sociologist Bruno Latour [Latour 2010], written discourse acts here as an intermediate being that is unable to know when it has to speak or to stay quiet and which is dominated by oral discourse. This present article thus aims to consider written texts in the aforementioned manner and by specifically analyzing the transformations of the corpus and “cover” notions; then inquiring about what happens to them in the digital turn. Are covers and the corpus desegregating in the process of “dépapérisation”, the idea of “de-paperization” according to the words of Jacques Derrida? The French philosopher gave an illuminating interview in 1997 (French version): “Paper or me, you know…”  [Derrida 2005]. Derrida compares “de-paperization” to the progressive shrinking of the Wild Ass’s Skin by Balzac

This article aims to delve into this process of “de-paperization,” and argues that the digital world does not represent only a loss of corporeality but eminently introduces new tensions, encounters with the body, and ways of collaboration. Part 2 serves firstly as a reminder that oral discourse and visual cultures have been superseded by written discourse for only a relatively short period of time within the Western framework. From Codex Zacynthius commentaries (6th century) to the five manuscripts of the Swiss novel by Charles-Ferdinand Ramuz If the Sun Were Never to Return (1937 1st edition), and the diverse Hamlet versions, I wish to recapture Western memory in its never-ending practice of perpetual annotating, rewriting and versioning. The inception of written material, its versioning as well as its relationship to visual and oral materials, leads to the enlightenment of its interaction with the topic of the body-corpus. Part 3 focuses on the relationship between corporeality and the digital material of writing, pointing to a new relationship between the body and the digital world. Finally, Part 4 will raise the question of closures and limits; leading to the examination of notions of anxiety as well as liberation.

The subtitle of this article includes “Some Digital Humanities fragments,” the last word being a translation from the French “éclats”, which can refer to fragments of wrath, light, brilliance or something broken. This subtitle points to the fact that Humanities is now present as fragments within digital culture. This process of Humanities’ fragmentation should draw Humanist scholars’ attention urgently to what the literary scholar Yves Citton designates as the Humanities’ core duty: interpretation. Considering Humanities as a social fact according to Latourian inspiration, Citton expresses his own task thus:

I would like to suggest that our “knowledge societies” are worthy to be analyzed first of all as interpretation cultures – and that to put at the forefront questions of interpretation has to lead us to deeply reconsider our vision of social interactions, as well as our knowledge mapping, the structuration of our academic institutions and the expression of our politics claimings [Citton 2010, l. 142–146].

A similar approach was also presented by the great DH scholar, Stefan Gradman at the DH 2013 conference in Lincoln, Nebraska. Commenting on the EU project DM2E, Gradman described the center of the Humanities field – including corpora, metadata, social contexts, references and dissemination/publication – as an “interpretative modelisation” [1]. Since interpretation is at stake, one should return to the beginning as Plato suggests in Timaeus 48b: let us reconsider the written discourse that “drifts all over the place [...and is] unable to defend or help itself” (Plato, Phaedrus 275e), and thus put the interpretative process at stake whilst looking for the fragments of digitized Humanities.

In 2012, Clivaz et al. underlined that the mass-scholarization of the 19th century led to the supremacy of printed literacy over other forms [Furet-Ouzouf 1977, 349–369]. This supremacy was however, rather short: between 1850 and 1980. This period is accompanied by the notable decline of the rhetorics in Germany and France, when rhetorical teaching at high schools and universities stopped, specifically in 1897 in France [Belhoste 1977]. In Germany, the work of Lucian of Samosata – a famous representative of Greek rhetoric historical writing [Samosata 2010] – was withdrawn from high school teaching in 1857 [Baumbach 2002]. Instead, Leopold von Ranke, the father of German historicism in contrast to Lucian, provided the basis of “annoying and farblos” historical writing [Ranke 2000, 4]. He contrasted historical communication with rhetoric and the use of pathos. In a 1964-1965 seminar titled L’Ancienne rhétorique, Roland Barthes emblematically presented rhetoric as already limited to memory and to the archives [Barthes 1970]. From that moment on, oral culture seems to have been almost totally forgotten in European historical and literary studies. This was to the profit of written texts that were considered potential containers for all that which is semiotic and thereby able to differentiate reality from the fictional.

Since the 1950s in the USA, oral cultures have recaptured scholars’ interest, notably in certain historical and sociological research areas. During this period, a preoccupation with oral history appeared alongside two other developments: research focused on the elites and institutions (Columbia School); and on marginal populations (Chicago School). These developments aided the emergence of alternative and hidden histories as well as their transmission by orality (Descamps, 2005). This return to orality is also present in the study of the notion of literacy, notably in the work of Walter Ong [Ong 2002]. These approaches have contributed to the development of a growing attention to plural literacies in the Human and Social Sciences. Yves Citton evokes these plural literacies in a Le Monde article in the following manner:

In a literature classroom, the point is to share the audacious gesture of interpretation, in the presence of the historical collective that makes us interpreters. It is related to the theatric or choreographic performance, or to the sportive performance, but also to the mystical initiation. [...] The interpretative gesture can be ‘performed’ only in the present [Citton 2013].

A look back in history shows that the “performed work” seems obvious in Antiquity, a cultural framework where orality is dominant, as the following musical example demonstrates. The rhetor Dio Chrysostomus (2nd century CE) speaks about “Homeric music” (musike), whereas his modern editor translates this as “Homeric poetry” [Crosby 1946, 362–363]. Crosby, in the first part of the 20th century, is unable to conceive that the Homeric work was predominantly “music” to ancient ears. Ancient culture and texts are full of musical indications that underline its importance, as shown in an a contrario way by Socrates’s ironic remark on public singers (the “rhaposdes”) and the actors who seem the be the authentic wise men (Plato, Ion 532d). In fact, the recurrent Platonic attacks on poetry, and arts in general, underline their importance; Plato himself uses assonance games, and rythmus with long sillabi (Plato, Laws 764de). Such a phenomenon can be observed even in the in Rev 18,22a or Rev 14,2, where Paolo Garuti considers the etymological word games as an attempt to reproduce something of the cithara sounds. He concludes that such phenomena belong to the cultural encyclopedia of that time: music was present in words and minds [Garuti 2013, 64].

It is more surprising – at least for scholars working on Antiquity, who often present an amnesia regarding the 16th and 17th centuries – to consider the impact of oral performance on the manuscripts of the Shakespearian Hamlet. Such amnesia has a powerful impact on the way in which one considers authorship in our present digital culture. If the “old audience” of Humanist scholars was trained to focus on relatively narrow historical periods, the new audience of Humanist PhD students, whatever they choose as topic, should be trained to obtain a deep knowledge of the history of authorship and of the writing material, from the roll to the screen. If one needs to be further convinced thereof, the Shakespearian case of Hamlet’s composition history is surely a good argument. Paul Eggert has recently presented a synthesis of the situation of the first three editions of the printed play dating from 1603, 1604-1605 and 1623. The first version is probably an adaptation of a play performed on the 26th July 1602, reconstructed from memory by the actors of the play and written to be sold to an editor, Nicholas Ling [Eggert 2013, 110]. The longer versions, however, notably the second, could be literary versions destined to be read rather than to be performed [Eggert 2013, 111]. In other words, Shakespeare had a genuine concern for his literary reputation and took care of it, a fact that has been claimed by many scholars since the 1980s. One is able to verify here the influence of spoken discourse on printed literature. Whereas the theatric performance influenced the most ancient version of the text, the aggregate formed by public discourse regarding the author has affected the longer versions. Shakespeare was apparently influenced by the diffuse presence of the public discourse on him. Borrowing from the terminology of the literary critic Jérôme Meizoz, one may say that this influence represented the trace of the “literary postures” in the middle of the 17th century [Meizoz 2007 and 2011]. Such a notion is confirmed in the following statement by the Shakespearian scholar Lukas Erne: “the first people who had a vested interest in the rise of dramatic authorship were not the playwrights themselves but the London printers, publishers, and booksellers eager to render respectable and commercially profitable what was initially an enterprise with little or no prestige”  [Erne 2013, l. 1765–1767].

The impact of others’ discourses – readers, commentators, newspapers and people in the street – on a printed text can be consistently traced: they influenced Erasmus and his annotations, as well as Shakespeare and his diverse rewritings. Even before printing, manuscript culture offered numerous traces of this impact. Let’s consider the Codex Zacynthius (6th century, palimpsest), where the Gospel according to Luke appears in the middle of pages whose margins are full of patristic commentaries. Certain folios even present two different versions of the Gospel text, one in the center of the page and the other inside the commentaries. However, in 1861, the modern editor Tregelles was chosen to edit only the central version of the text while ignoring the alternative versions present in the commentaries [Parker 2009, 113–119]. Such an editorial attitude, whose impact was valorized from Plato to Erasmus, leads to loose information and to the neglect of the commentaries – these annotations. Yet such was the printed literacy at its height that it believed it had the right to prune the “architext,” to return to Genette terminology: it believed it had the right to select, choose, and cut beneath the cover and the front-page, the “page de garde”. The French phrase “page de garde” designates the front-page of a book that has the task of being a “guard”: if we are to discard the protection offered by a book’s “cover” and the “guarding” duty of the front-page, are we losing something in digital writing? One can answer that the capacity to consider textuality beyond the boundaries of the cover and front-page was already present in Genette when he was describing the poetic object as “the architext,” as a network of excellence: “the architext is, then, everywhere – above, beneath, around the text, which spins its web only by hooking it here and there onto that network of architexture”  [Genette 1992, 83].

If one considers the manuscripts and printed texts of Charles-Ferdinand Ramuz from the 20th century, one may estimate that annotation and rewriting practices never stopped completely. In the 27th and most recent volume of the complete works of Ramuz, a computing tool allows the reader to compare the five versions of If the Sun Were Never to Return, dating from 1937 to 1942 [Sernier 2013]. The readers now have to explain whether they have read a version of If the Sun Were Never to Return from 1937, 1939, 1940, 1941, or 1942. Such a perspective unbinds the work from the book to make several versions or steps. The fluctuating text plays with the “guard” of the front-page. The cinematographic version by Claude Goretta (1987) occupies its own space as yet another version in a universe of plural literacies: it is the 1987 version of If the Sun Were Never to Return[2]. With respect to the form, one is able to verify here what Wido van Peursen refers to as constitutive of the digital culture: the “text” is perceived as a document [Van Peursen 2010]. In the middle of digitalized documents, unbound from their statuses as unique works, emerges the question of content communication; “to communicate a thought,” as an interviewer asked Derrida in 1997 during a seminal interview about the function of paper: “To what extent has [the paper] been adequate for you to communicate your thinking?”  [Derrida 2005, 41].

Before answering this question about the adequacy of paper to relate one’s thoughts, Jacques Derrida propounds an impressive perspective on the “paper-body”:

Ever since I started writing, both the institution and the stability of paper have been constantly exposed to seismic shake-ups. The beasts of relentless writing that we are could not remain either deaf or insensitive to this. Every sign on the paper had to be picked up as an advance sign: it foretold the “loss” of a support: the end of the “subjectile” is nigh. That is also, doubtless, where this body of paper has a bodily hold on us [Derrida 2005, 42].

Holding on to this “paper-body” perspective, this current section of the article will underline how Derrida frames this notion of fragmented textuality as a bodily disconnection within our digital age. Relying on the shrinking of The Wild Ass’s Skin, he discusses the inexorable shrinking of this “hyletic” material, recalling that the Greek “ule” also means “hood, forest” and “material” [Derrida 2005, 46]. How could the biblical scholars – to whom I belong – not be sensitive to what happens here, knowing that the word “Bible” itself supports notions of writing: papyrus is accorded the name “bublos,”, which refers to a plant named in the Lebanese region of the ancient city of Bublos. If one considers “liber” or “ caudex,” these Latin words also refer to the vegetal domain, specifically to the “hood” as represented by both parts of a book’s cover which maintain the folios inside. As Derrida summarizes it: “Paper is utilized in an experience involving the body, beginning with hands, eyes, voice, ears; so it mobilizes both time and space [Derrida 2005, 36]”. The same “shrinking” process could affect “a certain writing,” warns Derrida:

Can we speak then of abandon, arrest, or inhibition when designating the ongoing withdrawal or decline of a certain kind of writing: particularly the decline of steely writing with the point of a pen on the surface of paper, the decline of the hand, or at any rate of a specific and unique way of using the hand? If we were to associate this withdrawal with an effectual untying, namely the untying that effectively undoes the symbolic link of writing to walking. Thereby moving along, breaking a path, and untying the plotted connections between eyes, hands, and feet, then perhaps we would be dealing with the symptoms of another historical-, or as some would perhaps say, a posthistorical-phase. At any rate, another epoch could be hanging in the balance: keeping us in suspense, carrying off another scene, another scenario, keeping us distanced from, and raised above paper; all this according to another model of the prohibited. Therein lies a form of anxiety within the agenda [Derrida 2005, 54].

Seventeen years later, this anxiety is what is really at stake in public opinion. The USA has stopped teaching cursive writing to children [Doll, 2012], whereas French newspapers misunderstood this news and transmitted it as “the end of handwriting at school” [Luteaud 2013][3]. Taking Derrida into consideration as he imagined the shrinking of only “a certain writing,” but not without also conceiving this moment as “the earthquake that is happening sometimes leads to ‘losing one’s head’ or loss of ‘sense’”  [Derrida 2005, 58]. Perhaps it is worth recalling that western cultural memory does not stop to say it in a myriad of ways: body and books were jointly liable. With this in mind, one should examine the figure of Melany the Young, Christian literate in the fourth century CE. The life of Saint Melany, beyond the hagiographical tone, represents an interesting testimony on various aspects: individual consciousness, the form of books, the reading practices and the spiritual cross around the object of the “book” [Gorce 1962]. Married at the age of fourteen (§1), Melany risked death during the birth of her second child (§5), and at twenty years old, reached an agreement with her husband so that she could live in chastity (§6). The pretext was an imperative need to devote herself to God but evidently Melany focused on an intellectual and ascetic life; reading everything she found and copying the Old and New Testaments several times per year (§26). She also wrote small booklets called somatioi, “little bodies” (§23 and 36). There is a clear symbolic exchange: whereas Melany’s body stopped making children, she translated her fecundity to these “little bodies” that she wrote. This relationship between body and manuscript can be seen throughout the entire history of the codex, as animal skin parchments exemplify.[4]

One needs to consider the size of the loss, of the shrinking of this “paper-body.” After a moment of nostalgic reflection, one can then look closely at the next wave growing on the horizon: the new bindings, dependencies, hybrids and paradoxical relationships between the body and the digital material of writing. To consider the Digital Humanities for what they are or could be, one has to let them walk at their own rhythms. Humanities is “done” with fingers, according the Latin word digitus. Thus, one may refer to the hand-machine interface that one sees with the finger-print scanning on the iPhone 5S [5] or by discovering words “with the top of the fingers” as a Swiss newspaper titled the DH project EPFL-Venice [Fabre 2013, 36]. With symbolic and semantic sensitivity, Robert Darnton related the German word Fingerspitzengefühl – to be able to discover the world in details with the top of the fingers – to the emergence of digital screens:

We find our way through the world by means of a sensory disposition that the Germans call Fingerspitzengefühl. If you were trained to guide a pen with your finger index, look at the way young people use their thumbs on mobile phones, and you will see how technology penetrates a new generation, body and soul [Darton 2009, XII].

Even breath can lead us to a surprising body-machine dialogue as we noticed in a new form of multi-media publication, the eTalk, that we are developing as an interdisciplinary team in Lausanne: the software, Audacity, shares the discourse of a scholar in small pieces by following the rhythmus of their breath. “Sentences” in the eTalk are replaced by another measure: breaths that share the discourse in small pieces of 2-3 sentences each [Clivaz et al., 2015a]. In other words, the digital world does not represent only a loss of corporeality but, as previously stated, eminently introduces new ways of collaboration, tensions, and encounters with the body, with amazing new medical and IT findings such as the creation of an artificial skin.[6] If the body is at stake in a digital culture [Clivaz 2015b], the questions of closure and delimitation – notions so important in order to avoid a complete dissemination leading to madness – remain necessary and have to be reconfigured. It is thus an area of focus that requires examination.

How will we react to the anxiety provoked by the loss of the relationship between body and paper or by the so-called end of “handwriting teaching”? Temporally speaking, our first reaction when faced with an “out of the book” textuality collapsing into an infinite “architexture” would have been to develop a new form of scribal elitist culture with the most sophisticated methods of electronic encoding. Is this compatible with real DH dissemination? One would hope to see more efforts made in this direction of dissemination. Let us compare Wikipedia in its English and French versions: Wikipedia.fr allows anyone to write and upload an article without requiring basic HTML5 encoding thanks to a “visual editor,” whereas Wikipedia.org requires HTML5 knowledge to modify a page or to create an article.[7] With the introduction of a visual editor, it has been almost effortless to write an article on French Wikipedia. This is not a mere detail: it provides a way for allowing wider DH dissemination, resulting in the means to enroll a wide audience in the “wiki” process. The University of Geneva (CH) has started to organize open workshops to encourage and train women to contribute to the French Wikipedia’s articles: the possibility to circumvent HTML5 encoding allows contributors to reach diverse audiences and to raise the level of DH dissemination.[8] Time will tell how the situation evolves; as yet Wikipedia.org is still untransformed.

The emergence of a new scribal culture will not be a guarantee to us rediscovering the possibility of closures and delimitations. To recapture the notion of a limit, one should imagine the process in three steps. First, we have to keep in mind that manuscripts and printed cultures were also able to foster fear – fear of being overwhelmed by books and paper. The end of the Gospel according to John 21.25 claims that the world would not be able to contain everything that could be written about Jesus’ stories, reflecting an anxiety regarding a written knowledge able to absorb the world. Ann Blair, in Too Much to Know, refreshes one’s mind by helping one to escape the academic “amnesia” related to the 16th-17th centuries: she pleads for us to use the term “information age” anachronistically in a non technical way, underlining the idea that “information management” has accompanied the birth of the printed book [Blair 2010, l. 136]. She reminds us that “historians have pointed especially to three main sources of information explosion in the Renaissance: the discovery of new worlds, the recovery of ancient texts, and the proliferation of printed books”  [Blair 2010, l. 324–325]; in her book she expands this point of view with examples from cultures with limited or no contact with Western Europe. Such an approach, opening the historical gates to a thoroughgoing perspective, beyond Western cultures, is absolutely necessary to facing the anxiety one can face today. The building of a bridge between “old audiences” and “new audiences” is required. Such a platform offers a stable ground that one may move with Derrida from anxiety to the feeling of “out-of-paper liberation” that he expresses so strongly in the conclusion of his interview: “Because on the other hand, I also suffer, to the point of suffocation, from too much paper, and this is another spleen. Another ecological sigh. How can we save the world from paper? And its own body? So I also dream of living paperless – and sometimes that sounds to my ears like a definition or ‘real life’, of the living part of life. [...] Let’s not count the books. So paper expels me – outside my home. It chases me off. This time, it’s an aut aut: paper or me.”  [Derrida 2005, 64].

Firstly, we can also find a sense of liberation when one goes “out of the paper.” Secondly, one has to bravely assume that the objectivation of knowledge allowed by paper is ending. From the Modern duality of subject-object succeeds an era of intersubjectivity, of networking and graphs. The responsibility of subjects to transport knowledge and culture is increasingly at stake in such a digital framework. If Fahrenheit 451 by Ray Bradbury was a science-fiction novel in 1953, it sounds really less like that today. In particular it illustrates how much our own bodies are the covers of what we know and we transmit today. By surfing on the waters of the “web,” it is eminently our responsibility to define, enclose and limit the pieces of knowledge we still want to keep, preserve and transmit. In printed culture, we had the secure boundaries of “chapter, word, phrase, line,” elements that allowed us to consider texts as “massively addressable [objects] at different levels of scale”  [Witmore 2010]. Yet, as in the manuscript culture of the first centuries C.E., even these boundaries are not mandatory guarantees in the digital architexture ocean.

In consequence, a third step needs to be taken. It is surely not enough to innovate by shrinking [Goulet-Vinck 2009], we need a “creative fury” according to Citton’s statement: “to improve intelligence and make the world evolve”  [Citton 2010, l. 142–146]. In a quest for this “creative fury,” we can once more solicit the reserves of Western historical memory and return to the 17th century. To conclude, one may borrow the excellent remarks made by Olivier Abel, Ethics professor at the Protestant Institute of Theology (Montpellier/Paris), concerning the buccaneers of this century and the “capture anthropology” that emerges from this particular style of life. Olivier Abel underlines that:

The time of the buccaneers was particularly flourishing in the Caribbean between 1630 and 1670. In the new worlds, everything is offered with profusion by the divine Providence. [...] We are not in a gift and exchange economy any more, but in an economy of the “capture”, that stands even in the title of the Dutch philosopher Grotius On the Right of Capture. The history tempest has broken all links, and the pirate ship stands for the multi-religious and multi-racial utopia of a free adhesion, after the tempest, even if one adopts rules harder, as in an anti-reality. [Abel 2009a, 107]

The 17th century, with this focus on Grotius’ notion of the “right of capture” forms a link to this article’s Part 2; it thus proves fruitful to consider our digital transformation. Indeed, in 2011, Johanna Drucker made the now-famous proposition to switch from the notion of “data” to “capta”:

Differences in the etymological roots of the terms data and capta make the distinction between constructivist and realist approaches clear. Capta is “taken” actively while data is assumed to be a “given” able to be recorded and observed. From this distinction, a world of differences arises. Humanistic inquiry acknowledges the situated, partial, and constitutive character of knowledge production, the recognition that knowledge is constructed, taken, not simply given as a natural representation of pre-existing fact.  [Drucker 2011, §3]

The notion of “capta” can be related to the seldom-used French word “capitation,” which means to capture a part of heritage or some money.[9] Whatever it is on the digital ocean, or on the 17th century’s oceans, the act of capture seems to be the one required by new open spaces and thence to grasp some parts of our cultural heritage.

After describing such an atmosphere, Abel pursues his analysis in another article, arguing that out in the ocean there is neither king nor pope any more, one stands alone with God, one has left everything behind. Forced to live everyday without knowing what will come in the next, one quickly learns that it is impossible to possess the sea, to keep it in one’s fingers. Nevertheless, seafaring individuals are so unbound that they can contract new alliances, free alliances: “the right to depart is the condition of the capacity to be bound. The political question will thus gradually become: ‘How can we stay together?’ when we can always become unbound?”  [Abel 2009b, 115].

Everything is said in the notion of: “the right to depart is the condition of the capacity to be bound.” To exit the cover – to depart for lawless regions of the ocean – provides the right to leave, to depart. Since textuality has now – literally speaking – the right to depart from the book, it can also contract free alliances, with images, sounds, and all the other forms of texts. During the 17th century, “since on the ocean everything is going unbound, ceaselessly, one has to reconsider what are moorings, ropes, ties, knots and pacts”  [Abel 2009a, 108]. Today this is the role of new technologies – to give us the right to break free from the bindings and the front-pages of printed culture. This is an obligation, one could say, because it is impossible to possess the Internet ocean, to keep it inside of our fingers, inside our humanity. The right to capture, harvest, and select becomes the condition to bind, delimit and draw a virtual cover. Humanities out of the book, unbound, may force us to “go on board”! All our ways to net-work and to bind will be then have to be reconsidered.

With the kind permission of the editors, this English article is based on the translation of a forthcoming French article by Clivaz, C., “En quête des couvertures et corpus. Quelques éclats d’humanités digitales”. In Carayol Valerie, Morandi Franc (eds.), Le Tournant Numérique des Sciences Humaines et Sociales, Pessac, MSHA, 2015, p. 97-109. The author reformulated some sentences and expanded some passages in this English version. Many thanks are due to Harley Edwards for the English proof reading of this article. I am also very grateful to the two anonymous reviewers who brought important suggestions for improvements as well as rich bibliographical references to this article.