But the mere registry of these moral phenomena is not the full explanation of them. We must examine yet what they imply. From the faculty that perceives we must turn to look at the nature of that which is perceived. We may call the part already traversed the science of ethics, as dealing with and systematizing the facts of experience. The part that remains takes us into the metaphysics of ethics, as exhibiting the abiding verities so perceived and to which we find ourselves so responsibly related--not what is in us, but what is above and over us to which our moral consciousness corresponds. Having visited "the moral consciousness in its own home" and listened to its story of "right" and "duty" and "responsibility," we must go forth and explore the realm that answers to that story. This realm is the objective moral system to which human conduct is to be adjusted. The precise question of this chapter is whether the distinction of right or wrong, subjectively and psychologically made, is also objectively true and real, marking an actual qualitative difference in the deeds and intentions of men, or is a mere appearance, a fiction and illusion of our own minds. Is the principle of duty a reality for right life, as something belonging to the constitution of the world, or only an idea which our minds have manufactured--only our own thought reflected back upon us, as is our face that seems so real in the mirror? It would seem that the very asking of this question should be itself a sufficient answer. But doubt has been raised by speculative metaphysics. Hence we must examine it. ==Source of Doubt.==