diff --git a/Provider/Indexable.php b/Provider/Indexable.php
index 6946b54..c26da5a 100644
--- a/Provider/Indexable.php
+++ b/Provider/Indexable.php
@@ -82,7 +82,7 @@ class Indexable implements IndexableInterface
         }
 
         if ($callback instanceof Expression) {
-            return $this->getExpressionLanguage()->evaluate($callback, array(
+            return (bool) $this->getExpressionLanguage()->evaluate($callback, array(
                 'object' => $object,
                 $this->getExpressionVar($object) => $object,
             ));
diff --git a/Tests/Provider/IndexableTest.php b/Tests/Provider/IndexableTest.php
index f8a4564..e122ec1 100644
--- a/Tests/Provider/IndexableTest.php
+++ b/Tests/Provider/IndexableTest.php
@@ -73,6 +73,8 @@ class IndexableTest extends \PHPUnit_Framework_TestCase
             array('entity.maybeIndex()', true),
             array('!object.isIndexable() && entity.property == "abc"', true),
             array('entity.property != "abc"', false),
+            array('["array", "values"]', true),
+            array('[]', false)
         );
     }