When Alan Greenspan retired two weeks ago as chairman of the Federal Reserve, USA Today bade him a friendly farewell: "Inscrutable Fed chief leaves impressive legacy."
"'Inscrutable chief?'" mused one observer. "He wasn't all that inscrutable. Most of the time he was really pretty scrutable."
"Scrutable"? What a lovely word! It dates from around 1600 and means "capable of being scruted." No. I misspeak. It means, according to Merriam-Webster, "capable of being deciphered." Alas, "scrutable" has disappeared from English discourse, but when "inscrutable" bobbed up with Mr. Greenspan, the adjective prompted a few ruminations on the variant prefixes that enrich our lovely language.
We fortunate Americans, said Thomas Jefferson, are endowed by our creator with certain "unalienable" rights. Did he mean "unalienable" or "inalienable"? You may play it either way. The "un" spelling dates from 1611, the "in" from around 1645. Today, some opinionated editors would regard the preferred spelling as "inarguable" (1875). More contemporary authorities would choose "unarguable" (1881).
If you are looking for a "rule" to guide you in this cosmic puzzlement, or even a pattern to suggest a preferred spelling, you will look in vain. The great Henry Fowler examined "un" and "in" almost 80 years ago in his seminal "Modern English Usage." He concluded, with his familiar twinkle, that (USE ITAL FOR UPPERCASE PREFIXES) "there is often a teasing UNcertainty -- or INcertitude --" about the negative form of an adjective. He added:
"The general principle that 'un-' is English and belongs to English words, and 'in-' is Latin and belongs to Latin words, does not take us far. ... The first part, when asked to solve real problems -- whether, for instance, 'unsanitary' or 'insanitary' is right -- seldom gives a clear answer."
Fowler listed 31 puzzlers, ranging from "unacceptable" to "insusceptible," but he left out at least a dozen alternative pairs that will drive contemporary writers to their dictionaries. Today's lovers of the great Declaration probably would opt for "inalienable" rights, not because the "in-" form is newer, but because it pleasantly echoes the faint nasality of "certain." Try it on your ear. Perhaps "certain INalienable rights" has a mellifluosity that is lacking in "certain UNalienable rights." Hard to say. (Note that I did not make up "mellifluosity." The noun dates from the 15th century. It is not to be employed orally after two martinis or three bottles of beer.)
Over the past 200 years the prefixtual trend for adjectives of opposition has moved steadily in favor of "in" as distinguished from "un." Thus we find, e.g., secure/insecure, soluble/insoluble, capable/incapable, compatible/incompatible, animate/inanimate, and sane/nuts. But some "ins" are orphans. There appears to be no "ert" to go with "inert" and no "cessant" to match "incessant." It is amazing, how one passes one's time.
Often a search will be rewarded. I did not know until a week ago that there is a "delible" across from "indelible" and an "effable" next door to "ineffable." (Something that is effable "may be expressed in words," whereas "ineffable," a real tricker, can mean either "indescribable," as in "ineffable joy," or "unspeakable," as in "ineffable disgust.")
The adjective "inevitable" appeared in the 14th century and hatched "evitable" in the 15th. Contrariwise, the "fatigable" of 1556 fathered "indefatigable" in 1608. Three unprefixed words deal with sots and sottiness: ebriety, ebriosity and ebrious. A more familiar cluster also define the condition: inebriate, inebriation, inebriety and inebrious. Some lexicographer had one too many.