It would seem, at first glance, as if the development of reason should make conscience unnecessary.  When we are able to discern the consequences of our acts, formulate and weigh our motives and aims, what need of these vague pre-rational promptings and inhibitions?  Why not train men to supplant a blind sense of duty by a conscious insight, a rational valuation of ends and means?  Is not reason, as it has been recently called, “the ultimate conscience”? [Footnote:  G. Santayana, Reason in Science, p. 232; where also the following:  “So soon as conscience summons its own dicta for revision in the light of experience and of universal sympathy, it is no longer called conscience, but reason.”]

(1) Conscience is valuable on account of our ignorance.  Individually we have not had experience enough to guide us in our crises; conscience is the representative in us of the wisdom of the race.  In many cases we should never reason out the right solution of a problem; we lack the data.  But we can lean upon the racial experience.  Many past experiences, now forgotten, have gone to the molding of this faculty.  The need of action is often imminent, there is no time for the long study of the situation which alone could form a sure insight into the conduct it demands.  We need readymade morals.  Moreover, we are subject to bias, to individual one sidedness, and to the distortion of passion; in the stress of temptation we are not in a mood to reason judicially, even if we have the necessary data.  Altogether, insight, though in the long run the critic of conscience, is not a practical substitute.  What conscience tells us is more apt to be true than what at the moment seems a rational judgment.

(2) Conscience is also valuable in view of our rebelliousness.  Conventional morality is external, and would continually arouse revolt, were it not reinforced by an inward prompting.  If external motives and penalties alone bore upon us we should chafe under them, and under the stress of passion or longing throw them aside.  Even if these external sanctions were reinforced by insight into the rationality of morality, that insight might still leave us rebellious and unpersuaded.  Knowledge alone is feeble, marginal in our lives.  We often sin in the full knowledge of the penalties awaiting us.  We need something more dynamic, pressure as well as information.  Conscience is such a driver.  Its commands weigh upon us, and will not be stilled.  Reason plays but a weak part in the best of us; and to counteract our incurable waywardness, our recurrent longings for what cannot be had without too great a cost, we need not only the presence of law and convention, not only the weak voice of knowledge, but the stern summons of this powerful psychological response.  Nature was wise when she evolved this function as a bulwark against our weakness, a bit between our because of our forgetfulness.  Over and over again we say, “I didn’t stop to think.”  If our conscience had been