Book - Make it stick.. the science of successful learning argues that most of what we know as "forgetting" is just a loss/absence of a retrieval cue. We often cannot recall a certain piece of information, but given a set of choices, we are likely to pick the correct one. In this case, the knowledge is obviously not forgotten, but we lacked the cues to retrieve it from. It follows that an important step of learning is establishing powerful retrieval cues.
This importance for cues is another argument for Other than retrieval, encoding is a critical and often overlooked step when studying.
Looking at an example from pop culture, the food critic in Ratatouille certainly has not really "forgotten" his childhood meals, the context for retrieving these memories was just largely absent throughout his life.
Lastly, the authors also note that some forgetting (of cues) is also necessary for new learning, as we need to rid ourselves of outdated associations.