The Size and Shape of "Idea Space"

In a large idea management system it is very useful to have a general purpose "ideas like this" capability. Such a tool can be used to define a distance between two ideas, and with a distance metric it is possible to explore the dimensionality and size of a space. Using feature-based Jaccard-Tanimoto similarity, we find that "idea space" is consistently about 14-dimensional regardless of the origin or specifics of the ideas, which has some practical consequences for the behavior and display of similarity search results. In addition, given a distance within which people judge ideas to be "practically identical", the size of the universe of ideas can (whimsically) be estimated at 6 billion ideas.