It think you are incorrect in your last statement. All functors are inherently parallelisable. This means that any map operation is parallelisable. Also as l

It think you are incorrect in your last statement. All functors are inherently parallelisable. This means that any map operation is parallelisable. Also as long as the operations are associative (which is a surprisingly large number of cases), your reduce operations will also be parallelisable. That means that any computation that can be represented by a map/reduce is usually fully parallelisable and always paralellisable in the map operation. The only operations that aren't paralellisable are those that depend on the previous values (and even then you can make judicious use of partial function application to cut down on the dependencies). Basically this is where you have effects where order matters and recursive calls. I think the main reason we have difficulty imagining massively parallel computing systems is that we hold onto mutable state and imperative syntax. This pretty much forces us into a situation where order is significant. It seems to me that abandoning that idea is the key to freeing ourselves up, programming-wise. Personally, I don't find pure fp, or immutable OO that much harder than imperative. Different, for sure, but both have advantages and disadvantages.