If you have a single core/threaded computer you can only schedule one task at a time and concurrency is an illusion. What this functional language does is mask

If you have a single core/threaded computer you can only schedule one task at a time and concurrency is an illusion. What this functional language does is mask the complexity involved in SMP systems where state and data are subject to races via concurrent access. It also allows you to subscribe to the doomed philosophy of fail once, try again, try harder while ignoring the underlying cause. Trying the same thing over and over while failing has a name associated with it. It implements a separate scheduler which superimposes it's rules over what ever OS kernel scheduling is in place. Sometimes you don't want that complexity. It's functional. Who cares about functional as the _only_ model for a programming language?