I asked Rich Hickey, and this is what he had to say - "they differ from Haskell's type classes (from which they draw partial inspiration) in that the dispatch m

I asked Rich Hickey, and this is what he had to say - "they differ from Haskell's type classes (from which they draw partial inspiration) in that the dispatch map isn't an independent entity passed around by the type system, and thus can't do return-type based method selection, and generally in that they are not static-type-system-based."