 The book’s influence within philosophy was even greater. On the normative side, views close to its ideal consequentialism remained prominent and even dominant, at least in Britain, until the 1930s, though it is hard to know how far this is attributable to Moore himself since similar views had been widely accepted before him. In metaethics his non-naturalism likewise remained dominant for several decades, though here Moore played a larger role, especially for later writers, in part because of his general philosophical eminence and in part because of the vigor with which he presented the view. By talking explicitly of non-natural properties he at least seemed to give non-naturalism a more robust metaphysical side than predecessors such as Sidgwick had, and he defended the view more emphatically, in particular by putting more weight on the open-question argument. When Sidgwick noticed Bentham or Spencer equating goodness with a natural property such as pleasure, he thought it a minor slip that ought in charity to be ignored; Moore deemed it a decisive error that vitiated the philosopher’s entire system. By so emphasizing the two elements of non-naturalism – its realism and its commitment to the autonomy of ethics – Moore helped initiate a sequence of developments in 20th-century metaethics.