You can still do this in functional programming by programming functions that only interact with their arguments, and limiting what those arguments are. Additio

You can still do this in functional programming by programming functions that only interact with their arguments, and limiting what those arguments are. Additionally, in Clojure, you can in fact hide data by not exporting it from a namespace and only providing functions that operate on it in the namespace, and some other FP languages do this also. The difference is that within the namespace/module, all data is available to all functions, which is often easier to think about and organize than adding the complexity of marrying certain data to certain functions.