A housemaid may be deterred from going to meet her lover in the garden, because a howling ghost is believed to haunt the laurels; but she will go to him fast enough when she discovers that the sounds that alarmed her were not a soul in torture, but the cat in love.

The case of conscience is exactly analogous to this.
And now let us turn again to the case in question.

Men of such a character as I have been just describing may find conscience quite equal to giving a glow, by its approval, to their virtuous wishes; but they will find it quite unequal to sustaining them against their vicious ones; and the more vigorous the intellect of the man, the more feeble will be the power of conscience.

When a man is very strongly tempted to do a thing which he believes to be wrong, it is almost inevitable that he will test to the utmost the reasons of this belief; or if he does not do this before he yields to the temptation, yet if he does happen to yield to it, he will certainly do so after.

Thus, unless we suppose human nature to be completely changed, and all our powers of observation completely misleading, the inward condition of the class in question is this.