Auguring yesterday's events

Just ran across a nice coinage that is a) made from parts you already have around the house, b) is semantically logical, and c) does not involve the youth of today ruining English.

This is from an article in Wired about solar eclipses in the distant past:

Using the same calculating methods that predict future eclipses, astronomers have been able to calculate when eclipses occurred in the past. You can run the planetary clock in reverse as well as forward. To coin a word, you can postdict as well as predict.

Nice, eh? A niggling point is that they did not, or were not the first, to coin the word. (Google: 3,740 hits). But the term has what appear to be multiple slightly different usages. The Double-Tongued Dictionary provides this cite:

Approximately one in five suspect identifications from sequential lineups may be wrong. As a result, no existing eyewitness identification procedure can relieve the courts of the burden of decide after the fact (or postdicting) which eyewitness identifications are accurate versus inaccurate.

This sense seems relatively established in the literature of psychology, where its sibling term postdictor is flung about with abandon.

Postdiction is also used in a dismissive sense to refer to "prediction after the fact" by people who are skeptical of, you know, prophecies. Think Nostradamus.

For the general idea of running the clock backward, as the Wired article puts it, there is also the term retrodiction. As defined in Wikiepdia, retrodiction is a way to test theories by comparing against past results in situations when comparing against future ones is impractical. You see this in economics, when economic models are tested by running them against data from the past to see if your model can, for example, accurately predict the mortgage crisis. Some might say that this constitutes that other, more dismissive sense of postdiction, but hey.

As an interesting aside, the very next paragaph in the Wired article has this bold usage:

The most likely candidate for Thales' eclipse took place on May 28, 585 B.C., though some authorities believe it may have been 25 years earlier in 610 B.C. Hundreds of scholars have debated this for nearly two millenniums.

This invites a discussion of forming plurals for terms that immigrated from non-English sources. I have an opinion on that, actually, which you can read here.

Let pre-dom ring

The pre- prefix is good, clean fun, as many folks have noted. For example, in The Atlantic in November 1998, Corby Kummer had a cute essay[1] that was (ultimately) about pre-, which went along these lines:

I wear pre-washed jeans. I have outstanding loans for which I was pre-qualified and which I hope to pre-pay, and hold credit cards for which I was pre-selected and pre-approved. I make pre-retirement deductions from my pre-tax earnings. I pre-medicate before going to the dentist, because of a pre-existing condition. My children were pre-tested in advance of pre-school. They will clamor, I predict, to see the Star Wars prequel.

It's come up here before, where we noted pregaming and pre-buttal. Sort of along the lines of this last, today I found an entry on polyglot conspiracy in which Lauren makes this sad (but lingusitically amusing) comment:

... although I ought to feel invigorated and hopeful this time around by the impressiveness of many of the Democratic candidate options, as well as the real possibility that we could get a changemaker in office, I somehow still feel pre-defeated.

I know this feeling, don't you?

People occasionally complain about "illogical" uses of pre-, but I think we can agree that pre-boarding does mean something different than just plain ol' boarding, and that pre-announcing something is different than just announcing it. The beauty of the prefix is its flexibility in the terrain that it can occupy, ranging from the nominally logical "before" to the semantic areas of "anticipatory" or "preparatory" or just "early." And although the prefix can cover a lot of territory, I don't recall offhand any usages in which it was unclear what the intent was. Unless, of course, I'm post-remembering wrong.


[1] I am amazed, I must confess, that a link that I harvested nearly 10 years ago is still good.