The capacity to change with experience infuses our perceptions, thoughts, and actions in and about the past, present, and future. The cognitive system supporting this capacity for change can be exquisitely responsive to external events and yet can influence how those external events affect us. This interplay between the external and internal has been a major theme of my lab group's research. We proposed that the fundamental ambiguity of subjective experience requires ongoing reality monitoring processes for evaluating its veridicality and proposed a source monitoring framework for exploring the encoding, activation, and evaluation of information. We further proposed a functional architecture, a multiple-entry modular memory system, that characterizes component subprocesses of cognition that give rise to remembering and other subjective phenomena (e.g., knowledge, beliefs, emotion, consciousness, self). I first discuss these approaches and some issues they address and then describe some educational and professional experiences that provided opportunities to investigate this fascinating epistemological puzzle.