There should be a unification of various kinds of insurance in one general plan and under one general administration for the whole state. This should be done with full regard to the actuarial differences in costs as among various kinds of insurance, various trades, various establishments, and, to some extent, even the various individuals, so as to ascertain the costs and to distribute them equitably. Only in this way can provision be made for entire mobility of labor, so that men may not be bound, as a condition for obtaining benefits, to continue in the service of any one employer. To this end there should be interstate comity and coöperation, so that the insured could at any time transfer his actuarial equity from one state to another. § 17. #The contributory principle#. The contributory principle should be adopted, and both employers and wage-earners contribute to the cost in equal amounts. But further, the general public interests may be recognized through the payments in aid of the funds (subsidies, subventions). Both employers and employees usually seek to escape the burden, by getting the state to bear the whole expense[5] or by getting the other party to pay all or the larger part. But it is much to be desired that in large part the finances of a system of social insurance should be disassociated from the ordinary budgetary system of taxation and public expenditures. The fundamental reason why the premiums should be divided between employers and employees is that this is most favorable to the equal participation and coöperative efforts toward reducing the risk, and developing right industrial and political relations. Everywhere it is the practice to provide for representation nearly in proportion to contributions.