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Lines of Thought

Branching Diagrams and the Medieval Mind

We think with objects—we conduct our lives surrounded by external devices that help us recall information, calculate, plan, design, make decisions, articulate ideas, and organize the chaos that fills our heads. Medieval scholars learned to think with their pages in a peculiar way: drawing hundreds of tree diagrams. Lines of Thought is the first book to investigate this prevalent but poorly studied notational habit, analyzing the practice from linguistic and cognitive perspectives and studying its application across theology, philosophy, law, and medicine.

These diagrams not only allow a glimpse into the thinking practices of the past but also constitute a chapter in the history of how people learned to rely on external devices—from stone to parchment to slide rules to smartphones—for recording, storing, and processing information. Beautifully illustrated throughout with previously unstudied and unedited diagrams, Lines of Thought is a historical overview of an important cognitive habit, providing a new window into the world of medieval scholars and their patterns of thinking.

272 pages | 4 color plates, 27 halftones, 86 line drawings, 3 tables | 8-1/4 x 11 | © 2020

History: History of Ideas

History of Science

Literature and Literary Criticism: General Criticism and Critical Theory

Medieval Studies


"Even-Ezra's study is an excitingly original contribution to the histories of cognitive psychology and information design that explores the question of how people were thinking, not just what they thought. Focusing on the logical horizontal tree diagrams that are ubiquitous in the margins of European medieval university manuscripts and early printed books, she demonstrates with much detailed evidence how these diagrams—too often dismissed by historians as mere ‘doodling’ by bored beginners—functioned as a primary means for medieval scholars to visually comprehend their learning. A compelling example of the Extended Mind Theory now prominent in modern neuropsychology, this book will be of interest not only to medieval historians, art historians, and scholars of the book, but to anyone with an interest in information design and associative learning practices."

Mary Carruthers, New York University

"Even-Ezra roots the history of ideas in her probing analysis of habits of reading materialized in the horizontal tree diagrams that fill the margins of medieval university manuscripts. Lines of Thought places the relationship between spatialized patterns of visualization and scholastic thought, famously formulated by Erwin Panofsky, on an entirely new footing. Applying concepts from linguistics and cognitive science within a framework inspired by Extended Mind Theory, the author reconstructs coordinated habits of hand and mind that remain as critical today in literary criticism, cognitive studies, and computational linguistics as they were to medieval theology, philosophy, literature, logic, law, and medicine. A brilliant and utterly original book."

Jeffrey F. Hamburger, author of Diagramming Devotion: Berthold of Nuremberg’s Transformation of Hrabanus Maurus’s Poems in Praise of the Cross

Table of Contents


Part I

1 The Form: Chronological, Linguistic, and Cognitive Perspectives
1.1 Form: A Chronological Perspective
1.2 Form: A Linguistic Perspective
1.3 Form: A Cognitive Perspective

2 The Habit: On What, Where, Who, When, and How Often
2.1 Diagramming as a Form of Marginal Annotation
2.2 Parasitic, Embedded, and Tapestry Forms
2.3 Beyond the Classroom: French and Hebrew
2.4 Conclusion

Part II

3 Structures of Concepts: Distinctions
3.1 Natural Philosophy, Metaphysics, Ethics 
3.2 Biblical Distinctions
3.3 Canon and Civil Law 
3.4 Medicine
3.5 Conclusion

4 Structures of Language
4.1 Verse and Rhyme
4.2 Letter Writing (Ars Dictaminis)
4.3 Grammar

5 Structure of Texts
5.1 Orientation and Composition: Theological Questions
5.2 Analysis: Argument
5.3 Analysis: Biblical Narrative
5.4 What HT Diagramming Tells Us about the Scholastic Perception of Texts: Authors as Architects, Texts as Wisely Made Constructions 
5.5 Coda: Back to the Future—Parallels to the Divisio Textus in Twentieth-Century Narrative Analyses

Appendix: Latin and English Surface Text of the Book of Job Parsed and Numbered (Translation Follows the English Standard Version)


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