Reason is also concerned in judging of a description of cases, in which a modification of moral feeling arises from the complexity of actions,--or, in other words, from the circumstances in which the individual is placed. This may be illustrated by the difference of moral sentiment which we attach to the act of taking away the life of another,--when this is done by an individual under the impulse of revenge,--by the same individual in self-defence,--or by a judge in the discharge of his public duty.
There is still another office frequently assigned to Reason in moral decisions,--as when we speak of a man acting upon Reason as opposed to passion. This however is, correctly speaking, only a different use of the term; and it means that he acts upon a calm consideration of the motives by which he ought to be influenced, instead of being hurried away by a desire or an affection which has been allowed to usurp undue influence.
The important distinction, therefore, which these observations have been intended to illustrate, may be briefly recapitulated in the following manner. Our impression of the aspect of actions, as right or wrong, is conveyed by a principle in the human mind entirely distinct from a simple exercise of reason,--and the standard of moral rectitude derived from this source is, in its own nature, fixed and immutable. But there are many cases in which an exercise of reason may be employed, in referring particular actions to this standard, or trying them, as it were, by means of it. Any such mental process, however, is only to be considered as a kind of test applied to individual instances, and must not be confounded with the standard to which it is the office of this test to refer them. Right or virtuous conduct does, in point of fact, contribute to general utility, as well as to the advantage of the individual, in the true and extended sense of that term, and these tendencies are perceived by Reason. But it is neither of these that constitutes it right. This is founded entirely on a different principle,--the immutable rule of moral rectitude; it is perceived by a different part of our constitution,--the moral principle, or conscience; and, by the operation of this principle, we pronounce it right, without any reference to its consequences either to ourselves or others.