diff --git a/activerecord/lib/active_record/callbacks.rb b/activerecord/lib/active_record/callbacks.rb
index e4987ceb43a..2ffe9db693d 100755
--- a/activerecord/lib/active_record/callbacks.rb
+++ b/activerecord/lib/active_record/callbacks.rb
@@ -191,7 +191,7 @@ module ActiveRecord
         alias_method :destroy, :destroy_with_callbacks
       end
 
-      CALLBACKS.each { |cb| base.class_eval("def self.#{cb}(*methods) write_inheritable_array(\"#{cb}\", methods - (read_inheritable_attribute(\"#{cb}\") || [])) end") }
+      CALLBACKS.each { |cb| base.class_eval("def self.#{cb}(*methods) write_inheritable_array(\"#{cb}\", methods) end") }
     end
 
     module ClassMethods #:nodoc:
diff --git a/activerecord/lib/active_record/validations.rb b/activerecord/lib/active_record/validations.rb
index 2e4be21a69d..dda282115fc 100755
--- a/activerecord/lib/active_record/validations.rb
+++ b/activerecord/lib/active_record/validations.rb
@@ -49,7 +49,7 @@ module ActiveRecord
         alias_method :update_attribute_without_validation_skipping, :update_attribute
         alias_method :update_attribute, :update_attribute_with_validation_skipping
 
-        VALIDATIONS.each { |vd| base.class_eval("def self.#{vd}(*methods) write_inheritable_array(\"#{vd}\", methods - (read_inheritable_attribute(\"#{vd}\") || [])) end") }
+        VALIDATIONS.each { |vd| base.class_eval("def self.#{vd}(*methods) write_inheritable_array(\"#{vd}\", methods) end") }
       end
       
       base.extend(ClassMethods)