You should no longer assume that Google Closure Library namespaces can be reached globally because some dependency may have already loaded it. In order to future proof - ClojureScript now always loads goog.module in accordance with Closure’s guidelines as Closure Library may decide to convert any namespace into a goog.module at any time and simply drop support for global definition for that namespace. Clojure style REPL driven development is best supported by the original Google Closure namespace conventions.