Around 1956: "My next task was to prepare my course. Since none of the textbooks known to me was satisfactory, I resorted to the maieutic method that Plato had attributed to Socrates. My lectures consisted essentially in questions that I distributed beforehand to the students, and an abstract of the research that they had prompted. I wrote each question on a 6 × 8 card. I had adopted this procedure a few years earlier for my own work, so I did not start from scratch. Eventually I filled several hundreds of such cards, classed them by subject, and placed them in boxes. When a box filled up, it was time to write an article or a book chapter. The boxes complemented my hanging-files cabinet, containing sketches of papers, some of them aborted, as well as some letters." (p. 129)

Whoa, I just noticed that Manfred Kuehn's PhD is from McGill University, which is where Mario Bunge taught! I wonder if they crossed paths?

Cf. Mario Bunge (2012), Evaluating Philosophies, Dordrecht: Springer-Verlag, p. 182: The preceding pages suggest an objective yardstick to measure the worth of philosophies: By their fruits ye shalt know them: Tell me what your philosophy is doing for the search for truth or the good, and I will tell me what it is worth.

Robert King Merton

Bunge was a prolific intellectual, having written more than 400 papers and 80 books

1980s: "I always typed a few hours a day on a heavy and noisy IBM typewriter. Before converting to the Apple faith, I wrote down every interesting idea or possibly useful datum on 5 × 8 cards that I kept in card-boxes. But I used them only sparingly to write papers of books, for they were just random collections. Once an unknown American scholar phoned me to announce that he was about to commit suicide because he had failed to craft a general theory of ideas out of thousands of cards that he had filled in the course of a decade. He had been a casualty of dataism, the idea that knowledge of anything is just a collection of bits of knowledge." (pp. 273–274)

1985: "Another doctoral student who wished to work on technophilosophy was José Félix, a friendly Basque engineer whom I engaged as a house sitter while my family and I spent the long summer of 1985 in Mallorca. He seized this opportunity to photocopy all my unpublished essays and filing cabinet cards. The external examiner, who was familiar with my work, flunked José Félix's dissertation, alleging that it had been lifted from my publications." (p. 387)

Mario Bunge (1919–2020) was an Argentine-Canadian philosopher and physicist. Here are some excerpts from his book Between Two Worlds: Memoirs of a Philosopher-Scientist (Springer-Verlag, 2016) about his use of card-boxes

By the way, that quotation indicates one thing that Mario Bunge thinks knowledge is not: namely, knowledge is not what @ctietze has called the collector's fallacy. If you want to know what Bunge thinks knowledge is, I recommend his Epistemology & Methodology I–III, which are volumes 5–7 of Bunge's 8-volume Treatise on Basic Philosophy (in fact, it's 9 books since the third volume of Epistemology & Methodology is two books: parts I and II). See, e.g., Figure 7.3: "A scientific research cycle", on page 252 of Epistemology & Methodology I, Chapter 7, Part 2: "From intuition to method", and subsequent sections.