On the other hand, trade unionism in many indirect ways tends to have an effect in the opposite direction. By a constant adherence to certain broad policies, the trade union movement may contribute much to a realization of the conditions on which the idea of a general rate of wages is based. Such, for example, is the emphasis played by the trade union movement upon free and compulsory education, and the raising of the age of entry into industry. Such, also, is its advocacy of social legislation which is aimed to give more nearly equal opportunity to the lowest grades of industrial workers. Or, to take a third example, such is the result of the aid given by the skilled trade unions to the unskilled workers in their efforts to organize. Unionism works against the formation of relatively separate groups of wage earners to the extent that its activities contribute towards the achievement of equality of opportunity for all wage earners, and to the extent that the strong groups come to the assistance of the weaker. 5.--The main cause of the formation of relatively separate groups of wage earners, with different, though closely related levels of earnings have now been considered. As a result of these influences, it must be concluded that the determination of the wage level of each of the various groups of wage earners is a sufficiently independent process to make it necessary to account for it as such. The various groups of wage earners have relatively separate economic careers so to speak. The economic fortune of each group is not settled merely as part of one general process, though the economic fortunes of all are intimately connected. The wage situation is not to be explained as consisting of one basic level of wages with a series of equalizing differences; but rather as consisting of a series of wage levels, all of which are governed to a considerable extent by the same forces or conditions.[35] 6.--We can now pass on the final question which confronts us. How are the differences between the level of earnings of the relatively separate groups of wage earners determined? The factors which determine the relative levels of earnings of each of the different groups may be put into two sets. First, those factors in regard to which each group stands alone and separate. Second, those which arise out of the dealings between the several groups.