It is our business to discover such secondary principles, and in our instruction to lead the pupil to the recognition of them. The nature of the formulas of duty which we have in mind--formulas which shall express the generalized moral experience of civilized mankind, will appear more plainly if we examine the processes by which we arrive at them. An example will best elucidate: Suppose that I am asked to give a lesson on the duty of truthfulness. At the stage which we have now reached it will not be enough merely to emphasize the general commandment against lying. The general commandment leaves in the pupil's mind a multitude of doubts unsolved. Shall I always tell the truth--that is to say, the whole truth, as I know it, and to everybody? Is it never right to withhold the truth, or even to say what is the contrary of true, as, e. g., to the sick or insane. Such questions as these are constantly being asked. What is needed is a rule of veracity which shall leave the general principle of truth-speaking unshaken, and shall yet cover all these exceptional cases. How to arrive at such a rule? I should go about it in the following manner, and the method here described is the one which is intended to be followed throughout the entire course of lessons on duty. I should begin by presenting a concrete case. A certain child had broken a precious vase. When asked whether it had done so, it answered, "No." How do you characterize such a statement? As a falsehood. The active participation of the pupils in the discussion is essential. Properly questioned, they will join in it heart and soul. There must be constant give and take between teacher and class. Upon the fulfillment of this condition the value of this sort of teaching entirely depends. The teacher then proceeds to analyze the instance above given, or any other that he may select from those which the pupils offer him. The child says no when it should have said yes, or a person says black when he should have said white. In what does the falsehood of such statements consist? In the circumstance that the words spoken do not correspond to the facts. Shall we then formulate the rule of veracity as follows: Make thy words correspond to the facts; and shall we infer that any one whose words do not correspond to the facts is a liar? But clearly this is not so. The class is asked to give instances tending to prove the insufficiency of the proposed formula. Before the days of Copernicus it was generally asserted that the sun revolves around the earth. Should we be justified in setting down the many excellent persons who made such statements as liars? Yet their words did not correspond to the facts. Very true; but they did not intend to deviate from the facts--they did not know better. Shall we then change the formula so as to read: Intend that thy words shall conform to the facts? But the phrase "correspond to the facts" needs to be made more explicit. Cases occur in which a