  The final aspect of Moore's critical response to idealism concerns his rejection of the monism which was characteristic of British idealism. This is the holistic thesis that ordinary things are essentially inter-related in such an intimate way that they constitute together an ‘organic unity’ which is, in a sense, the only thing that ‘really’ exists, since it is the only thing whose existence is not dependent on the existence of anything else. This thesis is especially characteristic of Bradley's idealism, according to which the Absolute is the one real thing. In his early writings and in Principia Ethica Moore engages in a good deal of polemical criticism of this thesis, but it is hard to find any arguments against it, as opposed to a robust affirmation of a realist pluralism. Rather later, however, in his paper ‘External and Internal Relations’ (written in 1919) Moore focused on the idealist conception of internal relations which lies at the heart of the monist thesis. Moore's argument against the thesis that all relations are internal starts from the claim that the burden of proof lies on its supporters since it conflicts with our common sense conviction that things are not essentially inter-related in such a way that a change to one thing in one respect necessitates changes to everything else. Moore then argues that the best reason one could have for the thesis involves a logical fallacy; he shows how the thesis that all relations are internal might be plausibly, but fallaciously, inferred from Leibniz’ Law, the uncontentious principle that things which differ in their relations must differ in their identity. Simplifying a bit, and using Moore's concept of entailment (see below), his argument runs as follows: