Abstract: Autobiographical memory, both individual and collective, is a way of knowing about, and making sense of, the personal past. It is also notoriously politically fraught. On the whole analytic epistemology of memory has been committed to assumptions, and has focused on questions, that do not help to understand the role of memory in the justification of political conflict, hostility and affective polarisation. In this talk I provide an empirically informed account of autobiographical and collective memory that is fit for supplying such an understanding. I argue that we colloquially call “autobiographical memory” is to a large extent just a form of imagination known as mental time travel. Autobiographical memories turn out to be socially shaped narratives in the imagination that sustain self-understanding. Given this conception of a memory, memories can be truthful even when they include content that was absent in past experiences; they can also mislead despite preserving content from past experiences. I also show that autobiographical memories are also especially vulnerable to being shaped by dominant ways of selecting past events and framing their significance. For this reason autobiographical memories are prone to being hermeneutically unjust. In the second half of the talk, I focus on collective memories which are shared memories that are narratives that sustain collective identities. I apply the mental time travel framework to this kind of  memory to explain how collective memories can cause affective polarisation and are especially suited as justification for inter-group conflict. Finally, I deploy the framework to make sense of the idea that members of a social group can have genuine collective autobiographical memories of events that happened before any of the current members of the group were born.