By Alvin Alexander. Last updated: August 10, 2016
“In Erlang it’s OK to mutate state within an individual process but not for one process to tinker with the state of another process ... processes interact by one method, and one method only, by exchanging messages. Processes share no data with other processes. This is the reason why we can easily distribute Erlang programs over multicores or networks.”
Joe Armstrong, in the book Programming Erlang