These rules the will is not compelled or necessitated to obey. In every volition it is conscious of a power to do or not to do; but yet, as the will forms a unity with the intelligence, we take for granted that it will obey them, unless grounds for an opposite conclusion are apparent. But the only probable ground for a disobedience of these rules lies in a state of sinfulness,--a corruption of the sensitivity, or a disposition to violate the harmony and fitness of the spiritual constitution. Hence moral certainty can exist only where the harmony of the spiritual being is preserved. For example: God and good angels. In God moral certainty is infinite. His dispositions are infinitely pure, and his will freely determines to do right; it is not compelled or necessitated, for then his infinite meritoriousness would cease. Moral certainty is _not absolute_, because will being a power to do or not to do, there is always a possibility, although there may be no probability, nay an infinite improbability, that the will may disobey the laws of the reason. In the case of angels and good men, the moral certainty is such as to be attended with no apprehension of a dereliction. With respect to such men as Joseph, Daniel, Paul, Howard, and Washington, we can calculate with a very high and satisfactory moral certainty, of the manner in which they will act in any given circumstances involving the influence of motives. We know they will obey truth, justice, and mercy,--that is, the _first_ class of motives; and the _second_ only so far as they are authorized by the first. If the first class of motives are forsaken, then human conduct can be calculated only according to the influence of the second class. Human character, however, is mixed and variously compounded. We might make a scale of an indefinite number of degrees, from the highest point of moral excellence to the lowest point of moral degradation, and then our predictions of human conduct would vary with every degree. In any particular case where we are called upon to reason from the connexion of motives with the will, it is evident we must determine the character of the individual as accurately as possible, in order to know the probable _resultant_ of the opposite moral forces which we are likely to find.