Mill was thus the most prominent thinker of a time in which old systems of thought were being undermined. Natural science and the higher criticism were breaking up the foundations of authority in religion, and Mill's general method of dealing with habits of thought, no less than the direct plea for free thinking and free speaking contained in his treatise on _Liberty_, gave a wider scope to honest scepticism. He expressed approval of some of the new Socialistic projects. He was in favour of compulsory education, of the regulation of hours of labour, of Trade Unionism and co-operation, and he looked forward to a time "when the division of the produce of labour, instead of depending, as in so great a degree it now does, on the accident of birth, will be made in concert on an acknowledged principle of justice." The social problem of the future, he said, would be "how to unite the greatest individual liberty of action with a common ownership of the new material of the globe, and an equal participation of all in the benefits of combined labour."[290] His most original contribution to politics was his appeal for absolute equality of freedom for men and women, which was the first effective attempt to remove the class brand from women, and to abolish the aristocracy of sex. But his most valuable work, as has already been suggested, was not so much to sow new political ideas in the minds of his followers as to plough them for the reception of such ideas. He did not so much start them along new paths as set them to inquire whether they were right in remaining in the old, and whether there was any real danger in leaving them. As solvents of prejudice, Mill's works have not been surpassed by any. He promoted, not change, but the readiness to change; not Liberal measures, but {241} Liberal-mindedness. Thus persuaded to refrain from hasty judgments upon opinions, and to accept every new idea upon its merits, the rising generation applied itself to the working of the improved political machine. The Liberalism of the Government which was in power from 1868 to 1874 was displayed in the further application of old principles, no less than in the adoption of principles which were new. Religious equality was expressed in their Irish policy and in their treatment of education. Reforms in the Civil Service and the Army abolished more class distinctions in the public service. The new School Boards were another example of popular control of Government. Acts dealing with Trade Unions and the ownership of Irish land expressed the new theory of State interference with individual liberty, and Acts referring to women marked a great appreciation of them in comparison with men.