 Parfit develops an act-utilitarian answer to this question (Parfit 1984: 73–75). Act-utilitarians hold that morally right actions maximize the total expected sum of the utilities of all persons in the society. Parfit argues that voting might nonetheless maximize expected utility if one candidate is significantly superior to the other(s). If we add the benefits to each member of the society of having the superior candidate win, we get a very large difference in value. So when we multiply that value by the probability of casting the deciding vote, which is often thought to be about 1/100,000,000 in a United States presidential election, we might still get a reasonably high expected value. When we subtract the cost to the voter and others of voting, which is often quite low, from this number, we may still have a good reason to vote. 