What is () in Haskell, exactly?

Question

I\'m reading Learn You a Haskell, and in the monad chapters, it seems to me that () is being treated as a sort of \"null\" for every type. When I check

Answer 1

Yet another angle:

() is the name of a set which contains a single element called ().

Its indeed slightly confusing that the name of the set and the element in it happens to be the same in this case.

Remember: in Haskell a type is a set that has its possible values as elements in it.