 Some of Bradley’s metaphysical ideas are displayed in his defence of his moral philosophy. An example is his claim that the self is a concrete universal and that the ethical doctrines he criticizes are damaged by their reliance upon abstract notions of the self. The self is universal in that it retains its identity over time and through many different actions, thus collecting together the series of abstract particulars which make up its history in a way analogous to that in which the abstract universal red collects together its scattered individual instances (now often called ‘tropes’); it is concrete in that, unlike red it is a real non-abstract individual. For such claims to be fully convincing, a developed system in which the underlying metaphysical ideas are fully worked out is needed, as he himself admitted. But in this later working out, most of it in Appearance and Reality, the expression ‘concrete universal’ almost disappears from Bradley’s vocabulary, mainly because he eventually concludes that there can be only one such thing; nevertheless, the idea involved remains, reappearing in the form of the recurring theme that abstraction is falsification, and in this form is central to his logic and his metaphysics.