Neville Goodman’s metaphor watch: Uncommon words

neville_goodmanThere are some words that I keep having to look up. They are not common words, and in the intervals before seeing them again I forget what they mean. It took me years to remember that picaresque meant pertaining to rogues, rather than being a misprint for picturesque. I’m not absolutely sure what nugatory means, and I confuse it with insouciant. I’m careful not to use these words at all. I’m in favour of short, common words, to avoid being misunderstood or thought pretentious.

A news story about the finding of an Islamic holy text written over an earlier Christian text—scraps of manuscript expected to fetch around £100 000 at auction at Christie’s in London—brought up the word palimpsest, a word I confuse with palanquin. A (COD) palanquin is a covered litter for one person carried by bearers. There’s not much scope for metaphor there, and indeed there is only one entry in Pubmed®: palanquin was the codename of a nuclear test in 1965. But a palimpsest (COD) is a surface on which later writing has been superimposed, or something bearing visible traces of an earlier form. Although I didn’t recall ever seeing the word in a medical text, there were definite metaphorical possibilities.

They are well applied: to taxonomy, genetics, neurology, and immunology, among other disciplines. The embryology of higher creatures imposes later developments upon earlier ones. Having “palimpsest memory” means that new patterns can replace old patterns without destroying the integrity of the whole memory. But the word is so uncommon that it needs explanation. There is a review of how the ideas of immune function developed titled, “Immune cell identity: perspective from a palimpsest”, but palimpsest does not appear either in the abstract or in the text. Knowing the meaning, I think what it refers to is that each succeeding model of immune function shows the existing limits “beyond which another model needed to assume the lead”: except that this cannot be a perspective from a palimpsest; surely it is a perspective of a palimpsest. I suspect that most readers, if they didn’t know the meaning or look it up, will simply have ignored it.

“A probabilistic palimpsest model of visual short-term memory” does better. Its first mention in the text, as a model of memory with items overlaid, is followed in the next sentence by, “A conventional palimpsest is a manuscript… partly cleaned… [and] written upon again…”. Now readers are in no doubt, and so a useful word is properly borrowed from another discipline. A later article on the same subject explains that, “A network with palimpsest memory is able to learn new patterns one-by-one, while sequentially forgetting earlier patterns” but does not explain the word, nor reference the earlier article. Maybe the word is well known among memory neurophysiologists. In a 2014 paper, the authors describe their model as a palimpsest, citing an article from 1986. This was the oldest mention I could find: “New patterns are stored on top of previous ones, which get progressively erased. For this reason, such a memory may be figuratively termed a palimpsest.” The authors are quite right, but I think most readers will have needed a dictionary.

The palimpsest of a Qur’an copied onto a Christian bible fetched nearly £600 000.

Neville Goodman is a retired consultant anaesthetist and a writer. He is co-author of a book on medical English.

Competing interests: I have read and understood BMJ policy on declaration of interests and declare that my only competing interest is my co-authorship of a book about medical English.