What does it mean to know another person, and how is such knowledge different from other kinds of knowledge? These questions constitute an important part of what I call ‘second-person epistemology’ – the study of how we know other people. I claim that knowledge of other people is not only central to our everyday lives, but it is a kind of knowledge that is unlike other kinds of knowledge. In general, I will argue that second-person knowledge arises from repeated interactions with another person, and that it also requires employment of certain cognitive abilities and a unique kind of second-order knowledge.
This paper provides the framework for a second-person epistemology by examining some of our ordinary claims about what it means to know another person. I describe four conditions that typically characterize knowing another person. Then I describe the psychological grounds of knowing a person. Finally, I conclude with some thoughts about the unique symmetries of second person knowledge and the role of such knowledge in our broader epistemological endeavours.