1) Being able to describe it succinctly doesn't make it simple or easy. Mutability creates huge cognitive load. Every piece of mutability state adds exponenti

1) Being able to describe it succinctly doesn't make it simple or easy. Mutability creates huge cognitive load. Every piece of mutability state adds exponentially more possible states for you to keep in mind. 2)http://en.wikipedia.org/wiki/Tail_call http://en.wikipedia.org/wiki/Tail_call ("Tail calls are significant because they can be implemented without adding a new stack frame to the call stack.") 3) I don't know enough about implementing partial in other languages to comment on if it's more garbage than should be necessary.