Such persons assess non-violence as a tactic, rather than accepting it as a value in itself. John Lewis comes to the conclusion that under certain circumstances violence is a more effective method. Gandhi believes in non-violence both as a principle and as the most effective means of achieving his purposes. Every individual who looks upon non-violence as only a means, rather than as an end in itself, will accept or reject it on the basis of his estimate of the expediency of non-violent methods. Some come to the conclusion that violence can never be effective and therefore refuse to use it under any circumstances; others decide on each new occasion whether violence or non-violence will best serve their ends in that particular situation. In such cases the question is one of fact; the decision must be based upon the available evidence.

From the diversity of opinions that exist at the present time it is obvious that the social sciences are not yet ready to give an unequivocal answer to this question of fact. Since the values that men hold subjectively are themselves social facts which the scientist must take into account, and since they vary from age to age, community to community, and individual to individual, it may never be possible to find the final answer. Meanwhile the individual facing the necessity for action must answer the question for himself on the basis of the best information available to him. Even if he refuses to face the issue for himself and accepts the prevalent idea of our own day that violence is an effective means of achieving desirable purposes, he has actually answered the question without giving thought to it.

The potential tragedy of our generation is that the whole world has been plunged into war on the basis of the prevalent assumption that violence is an effective means of achieving high social purposes. Even that part of the planning for peace that is based upon maintaining international order by force rests upon this same assumption. If the assumption be false, mankind has paid a terrible price for its mistake.

Another assumption on which the advocates of violence act is that the use of physical force in a noble cause inevitably brings about the triumph of that cause. History gives us no basis for such an assumption. There is much evidence that force sometimes fails, even when it is used on the "right" side. Although the sense of fighting in a righteous cause may improve the morale and thus increase the effectiveness of an army, actually wars are won by the stronger side. It is a curious fact that on occasion both opposing armies may feel that they are fighting on the side of righteousness. Napoleon summarized the soldier's point of view when he said that God was on the side of the largest battalions. During the uncertain process of violent conflict, the destruction of human life—innocent and guilty alike—goes on.

Just as there is evidence that violence used in a righteous cause is not always successful, there is evidence that non-violent methods sometimes succeed. Without attempting to give the final answer to the question whether violence creates so much destruction of human values that its apparent successes are only illusory, we can say that the success or failure of both violence and non-violence is determined by the conditions under which both are used, and attempt to discover the circumstances under which they have been effective.

(1) No great social movement can arise unless the grievance against the existing order is great and continuous, or the demand for a new order is so deeply ingrained in the minds of the people in the movement that they are willing to expend great effort and undergo great sacrifices in order to bring about the desired change.

(2) The group devoted to the idea of change must be large enough to have an impact on the situation. This is true whether the group desires to use violent or non-violent methods. In any case there will be a balancing of forces between those desiring change and those who oppose it. All of the non-violent techniques we have considered require sufficient numbers so that either their refusal of cooperation, their participation in politics, or their practice of positive goodwill has a significant effect upon the whole community.

(3) The group that has a strong desire to bring about social change may be augmented in strength by the support of other elements in the population who do not feel so strongly on the issue. The less vigorous support of such neutrals may be the element that swings the balance in favor of the group desiring change. This "third party" group may also remain indifferent to the conflict. In that case the result will be determined solely by the relative strength of the direct participants. In any case, the group desiring change will be defeated if it alienates the members of the third party so that they join the other side. This latter consideration gives a great advantage to the practitioners of non-violence, since in our own day people generally are disposed to oppose violence, or at least "unlawful" violence, and to sympathize with the victims of violence, especially if they do not fight back. A definite commitment on the part of the reformers not to use violence may go far toward winning the initial support of the group neutral in the conflict.

(4) These conditions of success must be created through the use of education and persuasion prior to taking action. The sense of grievance or the desire for social change must be developed in this way if it does not already exist. Even such a violent movement as the French Revolution grew out of a change in the intellectual climate of France created by the writers of the preceding century. Only when a large enough group has been won over to the cause of reform by such an educational campaign can the second requisite for success be obtained. Finally, much educational work must be done among the less interested third parties in order to predispose them to favor the changes advocated and to sympathize with the group taking part in the movement of reform.

The final result of any social conflict is determined by the balancing of forces involved. Violence itself can never succeed against a stronger adversary, so those who desire to bring about social change or revolution by violence have to begin with the process of education to build a group large enough to overcome the violent forces which are likely to be arrayed against them. Even a violent revolution must be preceded by much non-violent educational preparation. But even when the group using violence has become large enough to overcome the physical force arrayed against it, its victory rests upon the coercion of its opponents rather than upon their conversion. Though defeated, the opponents still entertain their old concepts and look forward to the day of retribution, or to the counter-revolution. A social order so established rests upon a very unstable foundation. Revolutionaries have attempted in such circumstances to "liquidate" all the opposition, but it is doubtful that they have ever been completely successful in doing so. The ruthless use of violence in the process of liquidation has usually alienated third parties against the regime that uses it, and thus augmented the group that might support the counter-revolution.