> You can say "the list monad" reasonably because there is only one sensible implementation of (List a -> (a -> List b) -> List b) in Haskell. While this may b

> You can say "the list monad" reasonably because there is only one sensible implementation of (List a -> (a -> List b) -> List b) in Haskell. While this may be true, I think the main reason you hear "the list monad" in Haskell is that Haskell doesn't support multiple instances of a type class (such as Monad) for a single data type (such as List/[]); and the Prelude already includes such an instance, which then becomes the List Monad. This limitation is perhaps not often relevant for Monads, but it is sometimes relevant for other Algebraic structures. For example, there are two very common Monoids on Number: (Number, +, 0) and (Number, *, 1).