No matter how implicit or unaware of it the subject is, some sort of epistemological theory regarding the process of knowing underlies a subject's argumentive reasoning. What basis does one have for knowing what is true with regard to a topic? What are the criteria for accepting beliefs as true, rejecting them as false, or modifying them? In a sense, these are questions that the present investigation has been designed to answer, insofar as these epistemological standards are reflected in the argumentive reasoning that subjects display.

To the extent that they are aware of them, it may also be fruitful to ask subjects in a more direct way about their epistemological beliefs. Although the primary objective of this study was not to examine explicit, or conscious, epistemological theories, responses to a number of questions included in the interview provide some sense of subjects' epistemological thinking. Our findings in this respect are the topic of this chapter. These findings reflect forms of epistemological thought that broadly resemble those reported in previous investigations of naive epistemological theories, beginning with those of Perry (1970) and continued by a number of others (King, Kitchener, Davidson, Parker, & Wood, 1983; Kitchener & Fischer, 1990; Kramer & Woodruff, 1986; Leadbeater & Kuhn, 1989).

Most of the interview questions on which the analyses presented in this chapter are based occur at the end of the interview for each topic.