diff --git a/src/Specification.php b/src/Specification.php
index 22947b9f..a71a1d94 100644
--- a/src/Specification.php
+++ b/src/Specification.php
@@ -60,7 +60,9 @@ public static function anyOf(self ...$specifications): self
      */
     public static function closure(\Closure $closure): self
     {
-        return new self($closure);
+        return new self(static function (JsonPointer $jsonPointer) use ($closure): bool {
+            return true === $closure($jsonPointer);
+        });
     }
 
     public static function equals(JsonPointer $other): self