Now, I am not contending that these principles are free from difficulty in application. At many points they suggest difficulties both in theory and in practice, with some of which I shall try to deal later on. Nor, again, am I contending that freedom is the universal solvent, or the idea of liberty the sole foundation on which a true social philosophy can be based. On the contrary, freedom is only one side of social life. Mutual aid is not less important than mutual forbearance, the theory of collective action no less fundamental than the theory of personal freedom. But, in an inquiry where all the elements are so closely interwoven as they are in the field of social life, the point of departure becomes almost indifferent. Wherever we start we shall, if we are quite frank and consistent, be led on to look at the whole from some central point, and this, I think, has happened to us in working with the conception of 'liberty.' For, beginning with the right of the individual, and the antithesis between personal freedom and social control, we have been led on to a point at which we regard liberty as primarily a matter of social interest, as something flowing from the necessities of continuous advance in those regions of truth and of ethics which constitute the matters of highest social concern. At the same time, we have come to look for the effect of liberty in the firmer establishment of social solidarity, as the only foundation on which such solidarity can securely rest. We have, in fact, arrived by a path of our own at that which is ordinarily described as the organic conception of the relation between the individual and society--a conception towards which Mill worked through his career, and which forms the starting-point of T. H. Green's philosophy alike in ethics and in politics.