“Many circumstances,” you say, “will arise that will enable a bad man to steal into the place of a good one, and the good man will lose favor instead of the bad one; for appearances are deceptive, and it is these we trust.” Who denies it? Yet I find nothing else from which to form an opinion. These are the footprints I must follow in my search for truth, I have nothing that is more trustworthy; I shall take pains to consider these with all possible care, and shall not be hasty in granting my assent. For the same thing may happen in battle, and my hand, deceived by some mistake, may direct my weapon against a comrade, and spare an enemy as though he were a friend; but this will happen but rarely, and from no fault of my own, for my intention is to smite the enemy, and to defend my countryman. If I know that a man is ungrateful, I shall not give him a benefit. Yet if he has tricked me, if he has imposed upon me, no blame attaches to the giver because I made the gift supposing that the man would be grateful.
“Suppose,” you say, “that you have promised to give a benefit, and later have discovered that the man is ungrateful, will you or will you not bestow it? If you do so knowingly you do wrong, for you give to one to whom you ought not to give; if you refuse, you likewise do wrong — you do not give to one to whom you promised to give. This case would upset your conscience and your proud assurance that the wise man never regrets his action, or amends what he has done, or changes his purpose.” The wise man does not change his purpose if the situation remains as it was when he formed it; he is never filled with regret because at the time nothing better could have been done than was done, no better decision could have been made than was made; yet all that he undertakes is subject to the reservation: “If nothing happens to prevent.” If we say that all his plans prosper, and that nothing happens contrary to his expectation, it is because he has presupposed that something might happen to thwart his designs. It is the imprudent man who is confident that Fortune is plighted to himself; the wise man envisages her in both of her aspects; he knows how great is the chance of mistake, how uncertain are human affairs, how many obstacles block the success of our plans; he follows alert the doubtful and slippery course of chance, weighs uncertain outcome against his certainty of purpose. But the reservation without which he makes no plan, undertakes nothing, protects him here also.