But the short-cut revolutionist fails to realize the full force of the things about which he talks most, namely institutions as embodied habits. Any one with knowledge of the stability and force of habit will hesitate to propose or prophesy rapid and sweeping social changes. A social revolution may effect abrupt and deep alterations in external customs, in legal and political institutions. But the habits that are behind these institutions and that have, willy-nilly, been shaped by objective conditions, the habits of thought and feeling, are not so easily modified. They persist and insensibly assimilate to themselves the outer innovations--much as American judges nullify the intended changes of statute law by interpreting legislation in the light of common law. The force of lag in human life is enormous. Actual social change is never so great as is apparent change. Ways of belief, of expectation, of judgment and attendant emotional dispositions of like and dislike, are not easily modified after they have once taken shape. Political and legal institutions may be altered, even abolished; but the bulk of popular thought which has been shaped to their pattern persists. This is why glowing predictions of the immediate coming of a social millennium terminate so uniformly in disappointment, which gives point to the standing suspicion of the cynical conservative about radical changes. Habits of thought outlive modifications in habits of overt action. The former are vital, the latter, without the sustaining life of the former, are muscular tricks. Consequently as a rule the moral effects of even great political revolutions, after a few years of outwardly conspicuous alterations, do not show themselves till after the lapse of years. A new generation must come upon the scene whose habits of mind have been formed under the new conditions. There is pith in the saying that important reforms cannot take real effect until after a number of influential persons have died. Where general and enduring moral changes do accompany an external revolution it is because appropriate habits of thought have previously been insensibly matured. The external change merely registers the removal of an external superficial barrier to the operation of existing intellectual tendencies.