of letting errors alone at a given time.  That is another question, to be discussed afterwards.  You may have a thoroughly vicious and dangerous enemy, and yet it may be expedient to choose your own hour and occasion for attacking him.  ‘The passage from error to truth,’ in the words of Condorcet, ’may be accompanied by certain evils.  Every great change necessarily brings some of these in its train; and though they may be always far below the evil you are for destroying, yet it ought to do what is possible to diminish them.  It is not enough to do good; one must do it in a good way.  No doubt we should destroy all errors, but as it is impossible to destroy them all in an instant, we should imitate a prudent architect who, when obliged to destroy a building, and knowing how its parts are united together, sets about its demolition in such a way as to prevent its fall from being dangerous.’[8]

Those, let us note by the way, who are accustomed to think the moral tone of the eighteenth century low and gross compared with that of the nineteenth, may usefully contrast these just and prudent word? of caution in extirpating error, with M. Renan’s invitation to men whom he considers wrong in their interpretation of religion, to plant their error as widely and deeply as they can; and who are moreover themselves supposed to be demoralised, or else they would not be likely to acquiesce in a previous surrender of the universities to men whom they think in mortal error.  Apart however from M. Renan, Condorcet’s words merely assert the duty of setting to work to help on the change from false to true opinions with prudence, and this every sensible man admits.  Our position is that in estimating the situation, in counting up and balancing the expediencies of an attack upon error at this or that point, nothing is to be set to the credit of error as such, nor is there anything in its own operations or effects to entitle it to a moment’s respite.  Every one would admit this at once in the case of physical truths, though there are those who say that some of the time spent in the investigation of physical truths might be more advantageously devoted to social problems.  But in the case of moral and religious truths or errors, people, if they admit that nothing is to be set to the credit of error as such, still constantly have a subtle and practically mischievous confusion in their minds between the possible usefulness of error, and the possible expediency of leaving it temporarily undisturbed.  What happens in consequence of such a confusion is this.  Men leave error undisturbed, because they accept in a loose way the proposition that a belief may be ’morally useful without being intellectually sustainable,’ They disguise their own dissent from popular opinions, because they regard such opinions as useful to other people.  We are not now discussing the case of those who embrace a creed for themselves, on the ground that, though they cannot demonstrate its truth to the understanding,