Right now I have an initializer that does this: ActiveRecord::Base.send :has_many, :notes, :as => :notable ActiveRecord::Base.send :accepts_nested_attributes_for, :notes It builds the association just fine, except when I load a view that uses it, the second load gives me: can't dup NilClass from: /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/base.rb:2184:in `dup' /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/base.rb:2184:in `scoped_methods' /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/base.rb:2188:in `current_scoped_methods' /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/base.rb:2171:in `scoped?' /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/base.rb:2439:in `send' /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/base.rb:2439:in `initialize' /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/reflection.rb:162:in `new' /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/reflection.rb:162:in `build_association' /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/associations/association_collection.rb:423:in `build_record' /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/associations/association_collection.rb:102:in `build' (my app)/controllers/manifests_controller.rb:21:in `show' Any ideas? Am I doing this the wrong way? Interestingly if I move the association onto just the model I'm working with at the moment, I don't get this error. I figure I must be building the global association incorrectly.