The conscientious and consistent application of these two doctrines in settlement of wage controversies which involve the reconsideration of established differentials should result in the gradual building up of an ordered scheme of wage relationship, such as is sought. This scheme would rest upon fairly widely held ideas as to the most suitable basis for wage differences. It would not make greater call upon the human sense of fairness than must be made by any plan which hopes to secure industrial peace by getting all parties to industrial conflict to agree upon rules or principles for the settlement of the claims of each. Whether that aim, itself, is a fanciful one, need not be again debated here. 5.--Lest it appear that the above proposals have been put forward without giving due weight to their defects, it is now well to consider certain criticisms to which they may be fairly open. Two objections, in particular, are likely to be made. One is of practical nature, the other of a theoretical nature. They may be considered in that order. The objection of a practical nature is that it will not be possible to apply the suggested principles either accurately or consistently, and this for two reasons. Firstly, it may be asserted that the application of the proposed doctrines would require a scientific comparison of the characteristics of different kinds of work, which comparison is declared to be unobtainable. Secondly, it may be said that in order to fix such wage differentials as are reasonably certain to accomplish the ends for which they are set, it will be necessary to have a precise knowledge of many facts and forces. This knowledge may be declared to be unobtainable. No simple or very final answer can be returned to these doubts. It must be admitted that it will always remain difficult to compare occupations except in general descriptive terms. The relative training and talents required for different kinds of work, and the relative demands made upon the individual by different kinds of work will always remain, to a great extent, a matter of opinion. It is also true that only a general knowledge can be obtained of the factors governing the supply of any particular sort of labor at a given time, and the probable effect of any wage change upon that supply. The differentials which would be established from a consideration of such material could not claim to be more than a practical approximation to the differentials which would carry out the intention of the policy.