Dan Piponi wrote an article about this: "What Category do Haskell Types and Functions Live In?" (http://blog.sigfpe.com/2009/10/what-category-do-haskell-types-a

Dan Piponi wrote an article about this: "What Category do Haskell Types and Functions Live In?" (http://blog.sigfpe.com/2009/10/what-category-do-haskell-types-and.html http://blog.sigfpe.com/2009/10/what-category-do-haskell-type...) He says that the more fruitful connection between Haskell and category theory goes in the reverse direction. Rather than trying to define a category Hask, which would contain all Haskell programs including exceptions, "undefined", out of memory, and so on, and then see if there are any general theorems in category theory which would help us understand Haskell, we should do it the other way around. Look at a particular small Haskell program, consider all the different categories it could be interpreted in, and see if this gives us a better understanding of category theory!