Fig. 1. Retrodiction, retrospection, and prediction.

In one’s own life, one may draw on memory to retrospect (i.e., review or re-evaluate) the past or predict the future. This process is time-asymmetric since our own past is (typically) observed, whereas our future is not. When we make inferences about strangers' lives, however, we often have uncertainty about both their past and future, since we may have observed neither. We may retrodict the unobserved past and predict the unobserved future of strangers' lives.