diff --git a/src/clos/boot.lsp b/src/clos/boot.lsp
index 1e1fb6a4d..5077c3773 100644
--- a/src/clos/boot.lsp
+++ b/src/clos/boot.lsp
@@ -131,4 +131,7 @@
     (defmethod slot-unbound ((class t) object slot-name)
       (error 'slot-unbound :instance object :name slot-name))
 
+(defmethod slot-exists-p ((instance t) slot-name)
+  nil)
+
 ;;; ----------------------------------------------------------------------