diff --git a/gtsam/inference/Symbol.h b/gtsam/inference/Symbol.h
index 102761273..2d7ede8e7 100644
--- a/gtsam/inference/Symbol.h
+++ b/gtsam/inference/Symbol.h
@@ -33,8 +33,8 @@ namespace gtsam {
  */
 class GTSAM_EXPORT Symbol {
 protected:
-  const unsigned char c_;
-  const std::uint64_t j_;
+  unsigned char c_;
+  std::uint64_t j_;
 
 public: