It is startling to realize that some of our most cherished memories may never have happened—or may have happened to someone else. I suspect that many of my enthusiasms and impulses, which seem entirely my own, have arisen from others’ suggestions, which have powerfully influenced me, consciously or unconsciously, and then been forgotten. Similarly, while I often give lectures on similar topics, I can never remember, for better or worse, exactly what I said on previous occasions; nor can I bear to look through my earlier notes. Losing conscious memory of what I have said before, and having no text, I discover my themes afresh each time, and they often seem to me brand-new. This type of forgetting may be necessary for a creative or healthy cryptomnesia, one that allows old thoughts to be reassembled, retranscribed, recategorized, given new and fresh implications.

Sometimes these forgettings extend to autoplagiarism, where I find myself reproducing entire phrases or sentences as if new, and this may be compounded, sometimes, by a genuine forgetfulness. Looking back through my old notebooks, I find that many of the thoughts sketched in them are forgotten for years, and then revived and reworked as new. I suspect that such forgettings occur for everyone, and they may be especially common in those who write or paint or compose, for creativity may require such forgettings, in order that one’s memories and ideas can be born again and seen in new contexts and perspectives.

Oliver Sacks, author of Hallucinations and one of my favorite books about music, Musicophilia: Tales of Music and the Brain, wrote the fantastic essay Speak, Memory for The New York Review of Books. In it he explores the many ways in which we fool ourselves into believing that just because we think it, it is new, and just because we remember it, that it is true.