Carlyle observes, has less influence on the happiness of men than the condition of their livers. Considered as a source of pain, conscience bears a striking resemblance to the feeling of disgust. Notwithstanding the assertion of Dr. Johnson, I venture to maintain that there are multitudes to whom the necessity of discharging the duties of a butcher would be so inexpressibly painful and revolting, that if they could obtain flesh diet on no other condition, they would relinquish it for ever. But to those who are inured to the trade, this repugnance has simply ceased. It has no place in their emotions or calculations. Nor can it be reasonably questioned that most men by an assiduous attendance at the slaughter-house could acquire a similar indifference. In like manner, the reproaches of conscience are doubtless a very real and important form of suffering to a sensitive, scrupulous, and virtuous girl who has committed some trivial act of levity or disobedience; but to an old and hardened criminal they are a matter of the most absolute indifference. Now it is undoubtedly conceivable, that by an association of ideas men might acquire a feeling that would cause that which would naturally be painful to them to be pleasurable, and that which would naturally be pleasurable to be painful.(93) But the question will immediately arise, why should they respect this feeling? We have seen that, according to the inductive theory, there is no such thing as natural duty. Men enter into life solely desirous of seeking their own happiness. The whole edifice of virtue arises from the observed fact, that owing to the constitution of our nature, and the intimacy of our social relations, it is necessary for our happiness to abstain from some courses that would be immediately pleasurable and to pursue others that are immediately the reverse. Self-interest is the one ultimate reason for virtue, however much the moral chemistry of Hartley may disguise and transform it. Ought or ought not, means nothing more than the prospect of acquiring or of losing pleasure. The fact that one line of conduct promotes, and another impairs the happiness of others is, according to these moralists, in the last analysis, no reason whatever for pursuing the former or avoiding the latter, unless such a course is that which brings us the greatest happiness. The happiness may arise from the action of society upon ourselves, or from our own naturally benevolent disposition, or, again, from an association of ideas, which means the force of a habit we have formed, but in any case our own happiness is the one possible or conceivable motive of action. If this be a true picture of human nature, the reasonable course for every man is to modify his disposition in such a manner that he may attain the greatest possible amount of enjoyment. If he has formed an association of ideas, or contracted a habit which inflicts more pain than it prevents, or prevents more pleasure than it affords, his