diff --git a/src/Composer/Script/EventDispatcher.php b/src/Composer/Script/EventDispatcher.php
index 6c6d26b87..7dd1e1f1c 100644
--- a/src/Composer/Script/EventDispatcher.php
+++ b/src/Composer/Script/EventDispatcher.php
@@ -151,6 +151,6 @@ class EventDispatcher
      */
     protected function isPhpScript($callable)
     {
-        return false !== strpos($callable, '::');
+        return false === strpos($callable, ' ') && false !== strpos($callable, '::');
     }
 }