Thinking computationally, the graph of ideas in our minds is most likely sparse, as we can’t hold too many relationships in our mind at the same time. This is not a disadvantage, though, because following a few paths allows us to get to a lot of ideas: Intelligence isn’t just how much is stored in the brain, but also how much one can compute in a given time. For small n, the number of ideas that you can get to from a given idea following the edges of a sparse graph is exponential.