A great deal of criticism has been directed against the conclusion of Buckle that improvement in the state of mankind has chiefly resulted from an improvement in the intellectual outlook. And yet when stated with the necessary qualifications the generalization is as sound as it can well be. Certainly, the belief held in some quarters, and stated with an air of scientific precision, that the material environment is the active force which is ever urging to new mental development will not fit the facts; for, as we have seen, the environment to which human nature must adapt itself is mainly mental in character, that is, it is made up in an increasing measure of the products of man's own mental activity. The theory of the sentimental religionist that the evil in the world results from the wickedness of man, or, as he is fond of putting it, from the hardness of man's heart, is grotesque in its ineffectiveness. Soft heads have far more to do with the evil in the world than have hard hearts. Indeed, one of the standing difficulties of the orthodox moralist is, not to explain the deeds of evil men, which explain themselves, but to account for the harm done by "good" men, and often as a consequence of their goodness. The moral monster is a rarity, and evil is rarely the outcome of a clear perception of its nature and a deliberate resolve to pursue it. Paradoxical as it may sound, it demands a measure of moral strength to do wrong, consciously and deliberately, which the average man or woman does not possess. And the world has never found it a matter of great difficulty to deal with its "bad" characters; it is the "good" ones that present it with a constant problem. The point is worth stressing, and we may do it from more than one point of view. We may take, first of all, the familiar illustration of religious persecution, as exemplified in the quarrels of Catholics and Protestants. On the ground of moral distinction no line could be drawn between the two parties. Each shuddered at the persecution inflicted by the other, and each regarded the teachings of the other with the same degree of moral aversion. And it has often been noted that the men who administered so infamous an institution as the Inquisition were not, in even the majority of cases, bad men.[8] A few may have had interested motives, but it would have been impossible to have maintained so brutal an institution in the absence of a general conviction of its rightness. In private life those who could deliver men, women, and even children over to torture were not worse husbands or parents than others. Such differences as existed cannot be attributed to a lack of moral endeavour, or to a difference of "moral temperament." It was a difference of intellectual outlook, and given certain religious convictions persecution became a religious necessity. The moral output was poor because the intellectual standpoint was a wrong one.