 In the preceding example, it was tacitly assumed that the hearer had no prior belief (one way or the other) about the topic in question. His/her mind was completely open prior to receiving the testimony of the speaker. Now let us consider a different class of examples (modified from one given by David Christensen [2007]). Suppose that two people start out with opposing views on a given topic; one of them believes proposition p and the other believes not-p. To add a little color, consider an example in which two friends, Harry and Mary, have each acquired some evidence about a traffic accident described in the morning newspaper. Neither has any other evidence about the incident. For example, neither has any background knowledge or information about the people said to be involved in the incident. However, having read the newspaper account, both Harry and Mary form beliefs about it. Harry believes that Jones (described in the newspaper) was responsible for the accident. Mary believes that Jones was not responsible. Harry and Mary now run into each other, find out that their friend has read the same story, and discuss their views about the accident. To make the example even more interesting, suppose the two friends have as much respect for the other person’s judgment (in such matters) as they do for themselves. This might be based on the fact that when they have disagreed with one another in the past, each turned out to be right about 50% of the time. 