diff --git a/docs/user-guide/workers.md b/docs/user-guide/workers.md
index dd7235e..ad88212 100644
--- a/docs/user-guide/workers.md
+++ b/docs/user-guide/workers.md
@@ -251,9 +251,10 @@ computational tasks.
 
 ## Understanding limitations
 
-Workers have separate memory spaces. Each worker has its own memory, and
-you cannot share objects between workers or with the main thread. All
-communication happens via function calls with serialised data.
+Each worker is a separate Python interpreter, in a separate memory space,
+with a separate virtual filesystem. You cannot share objects between workers,
+nor with the main thread. All communication between them happens via function
+calls with serialised data.
 
 Only serialisable data can pass between threads. Function arguments and
 return values must be JSON-serialisable: numbers, strings, lists,