Articulating Intra- and Intertextual Relationships in the Fragment Collection

2.1 Semantic Web Technologies in the Personal Research Archive

The digital remediation of the Zibaldone did not begin with the aim to produce a digital edition of the text but with an experiment to model Leopardi’s notebook as a digital editing environment in response to its function as a personal knowledge base, and so, to support Leopardi’s methods of analysis and interpretation – a model that can be extended to and is informed by other representatives of the literary-philosophical fragment genre. The TEI data model adopted at the project’s onset has allowed us to articulate the stratified composition of the text, which is fundamental for representing the conceptual relationships between its semantic units; to link Leopardi’s references with their targets within the text, as well as between the Zibaldone and its indexes, and to describe their typologies; to define named entities (persons, works, places) with references to authority databases; to describe manuscript layout features, some of which contain key indications for determining the degrees of relatedness between the fragments. These markup decisions have been dictated by the need to define the semantic networks of the collection and parameters for assigning attributes of relatedness to their edges. Our editorial objectives to reconstruct the intratextual network of thematic relationships, to identify Leopardi’s sources through his bibliographic references, and to categorise the modalities in which he employs them, naturally align with the graph data model and the affordances of semantic web technologies to support the interpretative core of humanities research by

discovering, articulating, and visualizing relationships that may otherwise be difficult to investigate. (Usiskin et al. 2019, 191)

Semantic ontologies, linked open data, and network graph visualisations can serve as informational, analytical, exploratory, and narrative tools for bringing Leopardi’s fragments into epistemic structures of higher semantic orders – those implicit in the author’s discrete records of semantic annotation, those that readers could generate in research queries, and those inferred by machines.

The critical and practical efforts to bring about a paradigm shift in the modelling of digital scholarly editions by broadening the philological focus on the “text-as-document” towards modelling the “text-as-work” (Robinson 2013, 110) in order to “express and support the properties […] that construct its meaning” (van Zundert 2016, 104), and towards the “text-as-network” (Witt 2018, 221) to reflect the dominant activities of textual editors as “identifying and describing relationships between identifiable text parts” (223), broadly support our editorial model of Leopardi’s notebook as a digital workspace for text analysis and interpretation based on formalising the relationships between the various parts of the text. The digital assertive edition proposed by Vogeler to “use the information conveyed in the text as structured data” (2019, 318) further describes our focus on the thematic contents of the text and on representing its named entities as linked open data. In the objective to reconstruct the intertextuality of the Zibaldone, the project takes advantage of the semantic scholarly edition model advanced by Tomasi, and especially as employed in Bufalini’s Notebook (Daquino et al. 2020) which maps the semantic relationships between the authors and works discussed by Bufalini onto the notebook’s fragmented textuality and links them to the web of data. Semantic ontologies for intertextual relationships can formalise Leopardi’s critical engagement with other texts,⁵ and the publication as linked open data of the several thousand quotes and bibliographic references to works and their authors, editors, translators, and publishers, allows to build a comprehensive tableau of his sources by enhancing them with information from authority databases.

A congenial editorial model, in particular for representing the conceptual networks of Leopardi’s intratextual references and thematic indexes, is offered by Wittgenstein’s Nachlass which similarly records the author’s editorial annotations for structuring his collection of remarks by means of indexing systems indicating his “action intentions” (Pichler 2021, 197; italics in the original).⁶ The Zibaldone shares with the Nachlass its “‘crisscross’ knowledge” (Pichler et al. 2021, 60) characterised by “concept dynamics, vagueness, multiperspectivism, […] competing and contentious knowledge claims” (59). The Wittgenstein ontology maps the conceptual organisation of the fragments through philosophical subjects with subclasses, modelling different types of arguments and “chaining [them] into greater debates” (66). The “simple index structure, proven in the Gutenberg era” (Pichler, Zöllner-Weber 2013, 703), is employed as a main element of the Wittgenstein ontology to denote philosophical topics or “‘issues’” (704), and in our case would correspond to Leopardi’s indexes for the Zibaldone and their expansion by editors of print editions and by the project Lessico Leopardiano.⁷ The scope of an ontology for representing the conceptual structure of the author’s own records of text analysis could be extended through collaborative expert participation to include different modalities of argument. Their clustering into convergent and divergent “perspectives” – to borrow another term from the Wittgenstein ontology (Pichler et al. 2021, 69), would allow to represent, for example, the dialectical development of key binary notions in Leopardi’s thought. Besides the classification of thematic categories and arguments, the definition of typologies for the references and index headings, which our project infers from the author’s formal patterns of composition, would allow us to establish parameters for evaluating the degree of relatedness inherent in the intratextual relationships of the collection. This data of rich authorial analysis of semantic relatedness between text fragments then could be formalised for purposes of natural language processing.⁸

Semantic web technologies thus can assist scholars to analyse the relational structure of complex datasets which lack a formal discourse organisation but – as is the case of the fragment genre – present with copious indications for their conceptual modelling. Conversely, the research queries that necessitate their computational formalisation in the first place could inform the design of ontologies and of digital workspaces to lend definition to the process of interpretation itself. As Pichler et al. (2021) suggest, in order to advance the integration of semantic ontologies with the discourse of the humanities, ontology development needs to account for “non-shared conceptualization and contradiction between viewpoints,” to “reason over multiperspectivism, contentiousness, conceptual vagueness,” to “computationally map the dynamism of human knowledge” (71). Bradley and Pasin (2017) have proposed that integrating ontologies with a tool for supporting scholarly interpretation, such as Pliny,⁹ could help scholars bring emerging ideas from the note-taking and annotation stages towards clarity and formality, while acknowledging the limitations of existing graph-based data models for the “incompleteness and ambiguity” (2017, § 88) inherent in the process of interpretation. In its function as a personal knowledge base, the unbound codex of the Zibaldone accommodates the capture and storage of observations, while Leopardi’s analysis through referencing and indexing corresponds to the intermediate stage defined in Pliny as organising the notes “into a collection of interrelated concepts, categories, or topics” (§ 27) – a process which requires a technology to support the dynamic sorting, retrieving, aggregating, and re-arranging of research material on the scale of thousands interconnected fragments. While Pliny is a promising theoretical model of bringing ontologies to bear on the process of constructing interpretation, the design of such a workspace would benefit from case studies of intellectual notebooks which dwell at the project stage and employ organisational expedients to simulate the dimensions of a digital editing environment. The digital remediation of the notebook genre furthermore necessitates “synthetic frameworks” (Drucker 2013, § 38) in order to convey “fragmented and correlated points of view that resist self-evident reification” (§ 39). Drucker’s proposal to develop the design of interpretative humanities interfaces to

create environments that are constellationary, so that diagrammatic relations can be used to re-order familiar conventions through acts of generative, performative engagement (§ 39)

resonates with the exigency of the fragment collection for a workspace to support its hermeneutic practices. The creation of a computational model of the semantic organisation of the Zibaldone thus also entails the design of a research platform to configure its multi-perspectival discourse, and therefore can take advantage of and offer explorative ground for modelling authoring environments to support modular, fluid, networked, multimodal scholarship. Whereas “literal translations of a book into a non-book-oriented medium” (van Zundert 2016, 104) abound among digital scholarly editions, and “digital simulation of print monographs” (Spence 2018, 471) among emerging digitally-mediated long-form scholarly publications, some fragment collections emphatically fail to become books in an endeavour to convey the constellational order of their phenomenological discourse.

2.2 Activating the Relational Power of Ideas: Fragments and Thought-Images

Leopardi’s Zibaldone, Wittgenstein’s Nachlass, Coleridge’s Notebooks, Valéry’s Cahiers, Benjamin’s Passagenwerk, Joubert’s Carnets, Novalis’ Brouillon, among others, are kindred texts that capture the “infinitely resonant interconnectedness or relationality” (Gifford 1998, 303). The hermeneutic methodology of fragment writers magnifies the networked structure of meaning by repeatedly returning to phenomena from a multiplicity of contexts in an extended temporal and textual space:¹⁰

The same problems, regularly resurgent, are forever reformulated and reviewed, giving wider associations, sharper definitions, renewed perspectives and contexts of significance. (Gifford 1998, 46)

Their expansive perspective, which the Jena Romantics describe as “potentiation”,¹¹ raises the signifying power of ideas and renders increasingly scrupulous its articulation – the arranging of words in a sentence and the circumscribing of concepts in a discourse framework. The Zibaldone fragments contend with the challenge of semantic organisation already at the level of syntax which is laden with relative clauses, lists of synonyms and qualifiers, as reflected in the manuscript’s interlinear and marginal additions¹² – some integrated with pointers into a sentence while others positioned in parallel, before Leopardi confronts their relationality at the paragraph level with his combinatory methods of cross-referencing and thematic indexing. As the open space of the notebook expands in volume, contexts, and scale of observation, the correlations between fragments become convoluted, though they can gain form and clarity in a mental image described by Leopardi as

colpo d’occhio che scuopre in un tratto le cose contenute in un vasto campo, e i loro scambievoli rapporti.¹³

x

13  ‘The ability to take things in at a glance that discovers the things contained in a vast field, and their reciprocal relationships’ (Zib. 1854).

The simultaneous comprehension of the interrelations between many concepts which had been observed one at a time, fosters their qualitative re-evaluation and enhances the observer’s cognitive capacity:

Quindi è che scoprendo in un sol tratto molte più cose ch’egli non è usato di scorgere a un tempo, e d’un sol colpo d’occhio discernendo e mirando una moltitudine di oggetti, ben da lui veduti più volte ciascuno, ma non mai tutti insieme (se non in altre simili congiunture), egli è in grado di scorger con essi i loro rapporti scambievoli, e per la novità di quella moltitudine di oggetti tutti insieme rappresentantisegli, egli è attirato e a considerare, benché rapidamente, i detti oggetti meglio che per l’innanzi non avea fatto, e ch’egli non suole; e a voler guardare e notare i detti rapporti. ¹⁴

x

14  ‘Hence, in discovering all at once many more things than he would ordinarily be accustomed to notice at one time, and in discerning and seeing at a single glance a multitude of objects, each of which he has seen individually on many occasions but never all together (apart from in similar circumstances), along with them he is able to see all their reciprocal relations, and as a result of the novelty of this multitude of objects that presents itself to him all together, he is led to consider these objects, albeit fleetingly, better than he has done before this time, and better than he is used to doing, and to want to look at and note these relationships’ (Zib. 3269-70).

This superior cognitive experience prompts the thinker to want to look at the new relationships and to take note of them, so that the mental image can translate into interpretative discourse – 

purch’ei sia capace di ben esprimere i propri concetti, ed abbia bene e chiaramente e distintamente presenti le cose allora concepite e sentite.¹⁵

x

15  ‘Provided he has the things conceived and felt in that moment clearly and distinctly present before him’ (Zib. 3271).

Although it is conditioned by the application of close attention, such augmented perception cannot be purposefully attained; it is fleeting and its recollection is unreliable:

E forse esso stesso dopo quel punto, non crede più alle verità che allora avea concepite e trovate, cioè o non si ricorda, o non vede più con egual chiarezza, i rapporti, le proposizioni, i sillogismi, e le loro concatenazioni che l’avevano portato a quelle conseguenze.¹⁶

x

16  ‘And perhaps he himself after that point no longer believes in the truths that he has then grasped and discovered, that is, either does not remember or he no longer sees with the same clarity the relationships, the propositions, the syllogisms, and their concatenations that had brought him to those conclusions’ (Zib. 1976).

As the thinker endeavours to translate the conceptual order of relations into narrative, the synoptic image of the mind is simulated by visual metaphors and graphic configurations. Thus, for example, Walter Benjamin’s “flashlike image” is a “mode of cognition” (Weigel 2015, 347) very similar to Leopardi’s synoptic flash-like glance:

It stands for a way of knowing that in an instant can illuminate an entire situation. […] a faculty in which an ‘enhanced presence of mind’ (gesteigerte Geistesgegenwart)¹⁷ is coupled with an involuntary mode of seeing. The flashlike cognition is something that befalls the person unintentionally. (Weigel 2015, 348)

x

17 Weigel cites from Benjamin’s Das Kunstwerk im Zeitalter seiner technischen Reproduzierbarkeit.

Moreover, for Benjamin,

the tension of his writing becomes pictorially evident, almost to the extent of drawing itself, of composing itself in an image: in the figure-of-thought. (Desideri 2020, 14)

Indeed, the discursive methods that fragment collections employ to convey a conceptual image as “interrelatedness that is not stated but rather shown” (Brand 2004, 41) often rely on the spatial and visual semiotics of cross-references, index cards and indexes, folders, classificatory tables, catalogues, outlines, diagrams, page layout, underlining, geometrical figures, colours, connecting lines, shading, cutting and sticking pieces of paper, montage.¹⁸

The research framework of the Digital Zibaldone project explores how the phenomenological method of the fragment collection, of relating disparate ideas as they arise in an “intention-less” state of “immersion” (Benjamin 1998, 36) and their gathering into semantic constellations that resist an instrumental order of discourse, could be conveyed through the computational aggregation of the fragments’ metadata and their visualisation as semantic networks, thus replicating the inferences drawn by the flash-like image to support the interpretative process it engenders. By rendering the fragments readily accessible for recall and re-arrangement, their configurations could be examined anew with greater clarity and discernment. Beyond analysis, the visual hermeneutics of graphesis has potential to further mediate the interpretative process into discourse and create rhetorical forms that embody, rather than describe, the connecting threads of interpretation.¹⁹ In a basic sense, the research framework for the Digital Zibaldone recalls Engelbart’s vision for augmenting human intellect with a computer system that would make explicit the “types of network relationships among concepts” (Engelbart, English 1968, 398; quoted in Barnet 2013, 1325), which are embedded in language, and so would facilitate the human ability to

externalize [our] thoughts in the concept structures that are meaningful outside; moving around flexibly, manipulating them and viewing them. (Engelbart 1998, quoted in Barnet 2013, 1461-2)

3.1 Developing the Foundation of a Semantic Digital Edition

The Digital Zibaldone builds on a rich editorial history of scholarly print editions and some digital remediations of the text.²⁰ While editorial priority has been to reconstruct the author’s conceptual organisation of the fragment collection and facilitate its further analysis, rather than to produce a diplomatic edition which had been accomplished by the CD-ROM edition (Ballerini, Ceragioli 2009), at this mature phase of development the divergencies from a fully diplomatic edition are few.²¹ The transcription of the Zibaldone with its authorial thematic indexes and the encoding of their structural elements in XML according to the TEI P5 Guidelines are based on the CD-ROM edition, the facsimile edition (Peruzzi 1989-94), and on partial examination of the manuscript at the archives of the Biblioteca Nazionale di Napoli. The Roma tool of the TEI consortium was used to create a custom schema for the project, and was gradually modified with the addition of new elements. Based originally on the TEI Lite customisation, a custom schema was produced and exported as an ODD customisation and as a RELAX NG schema used to validate the project’s TEI files. The markup distinguishes significant layout features of the manuscript and charts the stratified and interlinked composition of the text with date divisions, marginalia, inline and interlinear additions, the targets of intra- and intertextual references, distinctions between heading categories of the indexes, some of the ink variations, several types of underlining. The edition also identifies quotes and their language, titles of works, miscellaneous bibliographic information, persons, and places, and provides editorial notes for corrections, normalisations, and additions, such as target specifications for Leopardi’s verbal references, with the number of encoded items being on the scale of 100,000. Besides the four authorial indexes, the dataset includes three editorial ones for persons, works, and places, with corresponding Wikidata and VIAF identifiers, biographical and bibliographic data, links to online encyclopaedia information and to the text of the works (of the edition cited by Leopardi, if available) on Google Books, the Internet Archive, Wikisource, and other open access digital resources.

For reasons of editorial expediency and limitations of resources for project development, the dataset has been hosted as a MySQL database with the provision to transfer it to a graph database once the TEI markup is completed, which was accomplished in the Spring of 2023. The database is used to store a search index and records of entries contained within the document with associated dates; it also contains tables storing representations of elements and element relationships in the form of nodes and edges, allowing for the generation of graphs and other metadata. The graph database transition will allow users to harvest the data more quickly and explore the networks between encoded entities dynamically in the context of the entire graph. The next phase of development will translate into RDF triples those entities encoded in the TEI that are relevant for defining the relationships between the textual segments, namely all of Leopardi’s targets of references (notes written in the margin and inline, paragraphs, paragraph sequences, and index headings), his date divisions, his mentions of works, persons, and places. Existing ontologies would allow to adequately describe the intertextual relationships based on the bibliographic references,²² but the main challenge in defining further the intratextual relationships is the need to lend semantic value to the edges in order to reconstruct the thematic networks of the fragments according to a hierarchy of relatedness. The properties of these relationships can be inferred from the layout of the text and Leopardi’s methods of composition, and have been described in the TEI.

The excerpt below [fig. 1] of encoding a Zibaldone date division consisting of a single paragraph (p. 1155,3) gives an example of some of the distinctive features of the text which constitute semantic entities. As can be seen in the facsimile, Leopardi uses date markers in parentheses at the end of a paragraph to mark his occasions of composition and to denote a circumscribed reflection as the main building block of the text. In this example, the date marker of the previous paragraph (visible on the first line of the facsimile excerpt) has the same date of June 11, 1821 but each of these is a separate date division. This function of the date division to mark a semantic unit is reinforced by the cases of thematic discontinuity between passages separated by identical date markers.²³ In the TEI, the date label replicates Leopardi’s date marker and has a range to reflect Leopardi’s use of compound dates (for example, “14.-15. Luglio. 1823”) or of multiple date markers written in the body of the same paragraph adding layers to the same reflection,²⁴ as well as of the time period of composition of the undated fragments (mostly in the first 100 pp.). These correlations between theme, paragraph, and chronology allow to compute thematic continuities and discontinuities across the collection.

Although Leopardi does not mark the paragraphs, they are clearly indented and he counts them in directing his intratextual references, as with one of the references here to the first paragraph on p. 1212 (“V. p. 1212. capoverso 1”). Each paragraph has been assigned an xml:id which serves as the target of most intratextual and index references. In identifying the targets, close reading was employed to ensure coherence with Leopardi’s count or when he does not specify a paragraph, as in the first reference on p. 1155,3 to p. 1117 (“Alla p. 1117”) which is part of the first paragraph beginning on p. 1116. This process is sometimes facilitated by reciprocal references, especially when there are multiple references in the same paragraph added in the margin or inline.

Some intratextual references are given a subtype describing the kind of relatedness they establish. In this example, the first reference is described as “subordinate,” which is inferred from Leopardi’s formulaic statement in the beginning of c. 14% of all paragraphs to indicate the continuation of a previous fragment. Thus, p. 1155,3 could potentially function as a footnote to p. 1117 (p. 1116,1) written a week and 38 pages later, however it splits the linear chain of reference into a network with references to two other locations in the manuscript – p. 1212,1 and p. 2318 (both subordinated to p. 1155,3), which in turn link to their own “subordinate” paragraphs [fig. 2]. These two references appear as additions at the end of the fragment and are nested in two separate inline notes [fig. 1].

Since the various kinds of additions often contain cross-references, as in this example, and those in the margin are sometimes reference targets (with an xml:id), they are encoded as notes with a location (interlinear, inline, margin, foot), which allows to represent statistically and explore Leopardi’s method of text analysis and semantic annotation in terms of chronology and perspective – whether there are correlations between establishing connections during the composition of the text (for example, when references are written in the middle of a sentence), as continuation of previous fragments, during re-reading, during the indexing stage, between fragments with reciprocal references and those that are only outgoing or incoming. For the purpose of generating such statistical data, the manuscript was consulted to record ink variations for notes containing paragraph references which are not always evident in the black and white images of the facsimile editions. The inline notes are typically written after or near the date marker, but sometimes there are multiple consecutive inline and marginal notes and their chronological layering can only be determined by the differences in pen and ink. Thus, the last reference in this example (to p. 2328) is in a separate inline note and marked with a different handwriting style from the rest of the text, but previous editions either do not make a distinction or represent both consecutive references (p. 1212 and p. 2328) as written in the same inline addition. This information can also be inferred from the fact that both fragments are “subordinate” to p. 1155,3 and the outgoing references on p. 1155,3 were likely written at the time of their composition.

3.2 Aligning the Semantic Layers of Intratextual References and Thematic Indexes

The document analysis and TEI markup have benefited from Leopardi’s rigorous attention to form in composing and editing the text. He adopts two main layers of annotation for navigating the fragments according to their semantic order: the map of intratextual references which are employed to indicate their generative relationship, to record associations during composition as ideas are elaborated further, and to establish them in retrospect; and the indexes which add thematic metadata to the associations and thereby exponentially increase the density of the network. For instance, p. 1329,3 has no direct intratextual references, but it is listed under several headings from the 1827 Index which thus relate it to 69 paragraphs in an extended thematic network on the subjects of grace, naturalness, affectation, etc. [fig. 3]. In the network visualisation clearly emerge those paragraphs between the several clusters which have most themes in common with the central node. The significance of the number of paragraphs listed under each index heading for determining the hierarchy of thematic foci of a fragment is evident in this paragraph which has no less than six different headings²⁵ but “Sgraziataggine” (Gracelessness) would be most applicable because it has no other references. By overlaying the reference network within the text with that of the index headings, we can compute the extent to which direct references overlap with those in an index theme, so as to better define their weight in the network. Within these two authorial methods of text analysis, the structural organisation of the collection suggests additional parameters for determining a hierarchy of semantic relatedness which will serve the modelling of the Zibaldone ontology.²⁶

3.3 Disambiguating Bibliographic Sources with Authority Databases

The complexity of thematic relations in the Zibaldone acquires another dimension through the several thousand references to texts and authors with which Leopardi engages and which are often at the centre of his inquiry. The TEI encoding identifies bibliographic references, titles, persons, quotes, and places as elements relevant to the bibliographic networks, and integrates Wikidata and/or VIAF identifiers for persons, works, and places [fig. 4].²⁹ This information is aggregated in editorial indexes which include links to the record in the authority files; an online encyclopaedia record; references to their paragraph and index locations; dates of birth and death for the persons; authors and editors for the works. Each title record also links to open access resources on the web that have the full text of the work, in order to create a virtual library for consulting these and, when possible, Leopa­rdi’s own editions. Additional bibliographic information included in Leopardi’s reference, such as volumes, subtitles, page numbers, date and place of publication, and publisher, will eventually be integrated from the spreadsheet used for preparing the data.

Whereas Leopardi’s bibliographic references often contain very specific information about the editions he is using, many quotes are not explicitly marked and there are numerous cases of intertextual derivation (quotes within quotes, references within references) which can be difficult to define because he frequently employs secondary literature and reference materials: anthologies, lexicons, articles in journals translated from other journals, critical editions of classical authors by multiple editors, book reviews. Disambiguating the relationships of citation through an ontology in order to articulate and visually represent their extended chains of derivation becomes indispensable, especially for references to the works of ancient authors which have been transmitted through encyclopaedias, biographers, and editors.

The difference in the presentation of intratextual relationships between the narrative style of a print edition’s apparatus embedded in the sequential reading of the text and the modular presentation of the digital environment which disambiguates and abstracts each record from its narrative stream in order to chart its relationships across the collection, can be of significant impact to the reader of a fragmented text which lends itself to numerous entry points and selective reading. Even at the basic hypertext interface, the identification of a work from Leopardi’s abbreviations and incomplete bibliographic references and the immediate access to its text already present in a synthetic form a lot of implicit and distributed information. The complete reconstruction of Leopardi’s network of intertextual references through linked data and semantic ontologies would create an augmented reading experience, in which their relations can be queried at various levels of granularity according to multiple parameters across and beyond the dataset. Wikidata, for example, allows to extract properties for persons and works, which can be harvested to create comprehensive charts with the genre of the work, its language and date of inception, and for persons their occupation, dates of birth and death, language, gender, country of origin, field of work, etc., and thereby guide various research questions.

4.1 Navigation Settings and Paragraph Information Box

The research platform presents the text by date divisions with a calendar menu, and employs Navigation Settings allowing a modular selection of manuscript markers and editorial additions to suit different reader purposes – quotes, for example, are italicised and can be easily distinguished in reading the text; the additions are integrated according to their indicated position in line of text but their markers can be shown or hidden; rhetorical underlining can be shown only, etc. One of these options is an information box linked to each paragraph displaying its first-generation references with incoming and outgoing paragraphs, index themes, persons and works mentioned, to show at a glance the topics of that fragment, and to direct the reader to its most relevant paragraphs, to Leopardi’s thematic indexes, and to the persons and works indexes [fig. 5].

4.2 Thematic Index Aggregates and Related Headings

Each index heading page [fig. 6] aggregates a list with hyperlinks to its paragraph references and to any sub-themes and referenced themes; the text of all referenced paragraphs (not displayed entirely); a statistical chart of the frequencies of the other index headings that also list these paragraph nodes; and a first-generation network graph (not displayed). The limitations of the MySQL database are most evident in this interface which slows down the dynamic harvesting of the data; alternatively, for the longer lists, such as PR and PNR, the statistical data is displayed as pre-generated images. A future addition to the related themes frequency statistics will be a list with links to the paragraphs that each of these headings have in common.

4.3 Network Graph Generation and Visualisation

At a more comprehensive level of aggregation the web platform allows to generate the network graph of first and second-generation relations of any intratextual references (paragraph, note, sequence), index themes, persons, and works, or a combination thereof, through a Node ID query by using their xml:id. While the interface for this query is under development at the time of writing, it is accessible at https://digitalzibaldone.net/?a=graph and was used to automatically generate the graphs in figures 2, 3, 7, and 8. The data can also be exported for custom manipulation in GEXF, GraphML, CSV, and JSON formats. A future functionality of this interface is a custom selection of types of nodes, which will allow users to pre-define the extent of the network according to their research criteria. The computational and diagrammatic challenge is to filter and arrange the interrelations according to a hierarchy of relevance in order to be able to follow intersecting paths through the extent of the network that is meaningful. For instance, including all the references from the more general PNR and PR index headings or some reference works, such as Forcellini’s Lexicon (the title with highest frequency), may be unfeasible to represent coherently and irrelevant at the level of paragraph nodes.³⁰

Figure 7 shows a second-generation network of a single paragraph, 2619,2 (large red node in the centre), which includes paragraphs, paragraph ranges, index themes, persons and works mentioned [fig. 7]. The graph allows to quickly identify points of connection among the thematic clusters for further exploration: 1570,1 (to the left of the main node) is not directly related to the main node (in fact, it lacks direct paragraph references altogether, as can be seen from its info box), but it is the connecting point between two of the main node’s index themes. Similar is the case of 3661,1 (to the right of the main node) which shares a direct incoming reference and an index theme with the main node, while checking its info box or extending the network to another generation shows that its immediate links are limited to these two, thus reinforcing its potential relevance to the main node.

While all of the bibliographic data is not yet fully integrated in a user-friendly interface, statistical frequencies show, unsurprisingly, that after the reference volumes of Forcellini, Du Cange and Accademia della Crusca, the most frequent presence is that of Cicero and Virgil, followed by Lucian, Plato, and Homer. However, it is only when we connect the authors to their works, to the contexts offered by the indexes, as well as to the chronology of the text, that we can begin to evaluate to what extent and how a particular work or author influences Leopardi’s thought. The network graph [fig. 8] of Homer’s Iliad shows several layers of interrelatedness: the paragraphs in which the poem is mentioned, the paragraphs to which they are directly referenced, persons, other works mentioned in these paragraphs, and the index themes of the paragraph nodes. The graph should be browsed dynamically to zoom in on different areas which can serve as entry points into the text for researching the thematic contexts in which the work is mentioned and how it is related to other works in Leopardi’s thought. We can easily identify those paragraphs in the immediate proximity which have none or few other themes and therefore likely address the main node most specifically – basic information which, however, cannot be gathered in the discursive space of the text. One of the closest paragraphs links to Cicero’s De Divinatione, in which Leopardi explores the intertextual relationship of translation. Expected correlations at a glance are the very close relation of the Iliad to the Odyssey and to scholarship on Homer, but how it is connected in the same paragraph (4406,2) to a volume on Finland and its inhabitants raises curiosity. In this case we cannot see an overview of that paragraph’s index themes because the last 231 pages are not indexed by Leopardi – and that is where user annotation would begin. On the other hand, outlier themes, such as “Sacerdozio presso gli antichi” (Priesthood among the ancients) on the far right of the graph, can suggest an isolated thematic focus which in this example Leopardi explores in the context of several other works. Statistical charts and networks graphs, thus, can lend concreteness and dimensionality to relationships that may be lost in the narrative form of the bibliographic reference and certainly are very difficult to discover in the fragmented space of the text.