It is here that differences of opinion may emerge: but must this really come to "strife" and "warfare"? May we not hope that, through love of mankind, or sympathy, or interest in the welfare of the whole, or some such noble motive, each class will freely divest itself of such of its privileges as stand in the way of others? I have already had occasion in another place to express my opinion on this point--that I look upon such well-intentioned judgment of average human nature as in contradiction with actual life. I have referred to the fact that conclusive proof for or against such a conception cannot be presented; that the final ground of decision rests in the depths of personal conviction on the part of the individual. But what offers some proof for the justification of the realistic opinion presented by me is the circumstance that history has as yet given no example of a free divestment of class privilege; at least I will say that every instance claimed as such may easily be invalidated. On the other side we have innumerable instances in history where such reform has been begun by well-meaning friends of humanity, theorists, only to be shattered soon on the _rocher de bronze_ of the strong self-interest of the threatened dominant class. They eagerly hold up before us unbelievers the night of the 4th of August, 1789, and they forget the hundred burning castles in France. They remind us of the Prussian agrarian reforms, and forget not only the French Revolution but also the Declaration of 1816. They remind us--but why add illustrations? Let such men prove authentically a single case in history in which a social class has against its own interests and out of altruistic motives made an essential concession. Certainly there have been conspicuous individuals who have done this; why not? We see this daily. But a whole class--never! If this is so, then the word of the great realist must be true, that "only strength conquers." So we find as the conclusion of our thought, first a difference of classes, then class interests, then class opposition, finally class strife. It is thus that Marx would have developed his theory of class strife, and easily, if he had chosen to proceed upon a psychological foundation.