This could be thought of as a form of digital, single-project zettelkasten dedicated to philosophy. It’s got people, sources, and ideas which are cross linked in a Luhmann-sense (without numbering) though not in a topical index-sense.
Interestingly it has not only a spatial interface and shows spatial relationships between people and ideas over time using a timeline, but it also indicates—using colored links—the ideas of disagreement/contrast/refutation and agreement/similarity/expansion.
What other (digital) tools of thought provide these sorts of visualization affordances?

Here’s a surprisingly useful thinking tool for anybody interested in the history of Western philosophy: a sort of garden of forking paths of argument. https://t.co/AH1ophVXH8
— Daniel Dennett (@danieldennett) October 9, 2018