 How is it that humans so often ignore the call of duty? The answer lies in the other motivational forces in our nature, such as self-love, desires, and the emotions, which can conflict with dutifulness. But we are not helpless in the face of these impulses; we can resist at least some of them at will, and we can learn to control them better by developing our character. How our character develops is to some extent under our control because personality traits can be strengthened or weakened by practice. Since we are imperfectly rational, we should strive to modify our desires and feelings so that it is easier for us to do our duty.