instinct is therefore no reason for regarding it as unalterable.
This applies to people's instinctive likes and dislikes as well as to their other instincts. It is natural to men, as to other animals, to like some of their species and dislike others; but the proportion of like and dislike depends on circumstances, often on quite trivial circumstances. Most of Carlyle's misanthropy is attributable to dyspepsia; probably a suitable medical regimen would have given him a completely different outlook on the world. The defect of punishment, as a means of dealing with impulses which the community wishes to discourage, is that it does nothing to prevent the existence of the impulses, but merely endeavors to check their indulgence by an appeal to self-interest. This method, since it does not eradicate the impulses, probably only drives them to find other outlets even when it is successful in its immediate object; and if the impulses are strong, mere self-interest is not likely to curb them effectually, since it is not a very powerful motive except with unusually reasonable and rather passionless people. It is thought to be a stronger motive than it is, because our moods make us deceive ourselves as to our interest, and
