The term "existing experience" refers to any past or present experiences that an individual has had. It can include personal encounters, events witnessed by others, and anything else that a person may have experienced in their lifetime. This concept is often used when discussing psychological theories such as cognitive behavioral therapy (CBT), where the goal is to help individuals change negative thought patterns or behaviors by examining their existing experiences and identifying any distorted thinking or beliefs. In essence, "existing experience" refers to an individual's personal history of interactions with the world around them.