PhilosophyIdeas is a searchable database of philosophical ideas compiled by Peter Gibson and built by Martin Berry. Users can search and sort ideas by theme, author, and text. The site has been around for years, but somehow escaped my attention until recently when I saw a tweet from Gibson: “Latest upload. Now over 17,000 philosophical ideas in the catalogue, each one of them a potential life-changer.” 17,000 ideas. That’s a lot of work.

From a page explaining the site:

The big thought behind the project is that philosophy has became such a vast and specialised subject during the last hundred years that not even the most learned student can keep track of it. The obvious next step seems to be the production of a clear and comprehensive map of what has been achieved. PhilosophyIdeas is meant as a tiny contribution to that task, though it began as a tool for helping students to write essays.

If you click on “explore the structure” and drill down a few levels, you can get a sense of how the site is organized. For example:

Start at the explanation page, check out the advice page, and have fun.

Also see the Indiana Philosophy Ontology (InPhO) Project.