 Consider the case of a public library. Suppose that a certain library is part of the common good in a political community because it serves an interest in the privileged class of common interests. Suppose the relevant interest is an interest in guaranteed access to the storehouse of human knowledge. Some individual X owns a bakery. Her bakery is profitable, but it would be even more profitable if people were not able to read certain cookbooks at the library and so could not make her carrot muffins at home. X has an interest in guaranteed access to the storehouse of human knowledge, but she also has an interest in her bakery’s profitability. If her private interest in a muffin monopoly is more important from her egoistic perspective than her interest in guaranteed access to the storehouse of human knowledge, then she is actually worse off because of the public  library.[5]  In this case, the public library is part of the common good, but it is not a public good because there is someone in the community who is worse off in virtue of the library’s existence.