In both cases supposed, and in like manner in all supposable cases, there is plainly a basis on which, in any given circumstances, we may foresee and predict volitions. There is something "that is evident and now existent with which the future existence of the contingent event is connected." On the one hand these predictions exert no necessitating influence over the events themselves, for they are entirely disconnected with the causation of the events: and, on the other hand, the events need not be assumed as necessary in order to become the objects of probable calculations. If they were necessary, the calculations would no longer be merely probable:--they would, on the contrary, take the precision and certainty of the calculation of eclipses and other phenomena based upon necessary laws. But these calculations can aim only at _moral_ certainty, because they are made according to the generally known and received determinations of will in a unity with reason and sensitivity; but still a will which is known also to have the power to depart at any moment from the line of determination which it has established for itself. Thus the calculations which we make respecting the conduct of one man in given circumstances, based on his known integrity, and the calculations which we make respecting another, based on his known dishonesty, may alike disappoint us, through the unexpected, though possible dereliction of the first, and the unexpected, though possible reformation of the latter. When we reason from moral effects to moral causes, or from moral causes to moral effects, we cannot regard the operation of causes as positive and uniform under the same law of necessity which appertains to physical causes, because in moral causality the free will is the efficient and last determiner. It is indeed true that we reason here with a high degree of probability, with a probability sufficient to regulate wisely and harmoniously the affairs of society; but we cannot reason respecting human conduct, as we reason respecting the phenomena of the physical world, because it is possible for the human will to disappoint calculations based upon the ordinary influence of motives: e. g. the motive does not hold the same relation to will which fire holds to combustible substance; the fire must burn; the will may or may not determine in view of motive. Hence the reason why, in common parlance, probable evidence has received the name of moral evidence: moral evidence being generally probable, all probable evidence is called moral.