The standard kilogram is losing mass! A couple of keys weigh less than they used to, or anyhow one key does.  And it's not just the customs man's fault (though the article does say that best practice is now to ship replica standard kilograms in diplomatic pouches).*  This conundrum made me go back (as everything should) to Wittgenstein.

In his I'm-really-a-little-smarter-than-Wittgenstein mode, Saul Kripke tries to undercut Philosophical Investigations §50, especially the aphorism whose oft-quoted translation (by Elizabeth Anscombe) runs: "There is one thing of which one can say neither that it is one metre long, nor that it is not one metre long, and that is the standard metre in Paris."

Kripke argues against this in making his crucial distinction between necessary and a priori truths, in Naming and Necessity.  (The Parisian meter's length, for Kripke, is a contingent a priori truth.) In the book and in class he defended the claim hilariously: Imagine thieves break in to the International Bureau of Weights and Measures, where the standard meter used to spend its timeless time, in order to leave a counterfeit standard meter and hold the real one for ransom. They need to make it look as though the meter stick is still there while they make their getaway, so they plan to leave a fake one instead of the real. But in order to prove that they have the real one, the substitute they bring with them is measurably different from a meter, say by about half a centimeter. They're apprehended, but the Sûreté doesn't know whether they've made the switch yet. They send a flic to a local hardware store to buy a meter stick and measure the real and the fake. One of them is just about a meter long, the other is bit longer. It's clear that the first is the standard meter: they've measured it and it's a meter long, darn it.

Thus the length of the standard meter, he says, is a contingent a priori truth.

Anyhow, it's striking me today that the trouble with the attack on Wittgenstein is that the verb he uses is aussagen, not sagen; but Anscombe translates that word with the "say" bolded in my quotation. It would be better to translate aussagen as "declare" or "find" in the way that a jury finds someone guilty or not guilty: it's a word that means something like: to ascertain and declare the result of what you've ascertained, to establish a fact.  So what Wittgenstein is saying (not a hugely controversial point in itself but really important for what he's about to say about paradigms in our language) -- what LW is saying is that you can't go and measure the standard meter in Paris in order then to produce new information, to predicate and declare of it that: it's a meter long!

If you need to measure it, as in the scenario Kripke spun, it's because it's no longer the standard meter. Now the hardware store meter has become standard, even if only temporarily.

And the standard meter is now measured as the distance light travels in a vacuum during a time interval of 1/299,792,458th of a second. Does it make sense to think that you can't say of that distance either that it is or that it isn't a meter? No: of course it's a meter and you can say (sagen) it. You just can't determine (aussagen) the fact that that distance is a meter long by measuring it.

But this might suggest where the missing platinum is.  Thieves broke in and took the original, and it says here that any day now they'll be trying to extort some ransom. 

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*From the Times article:

Because of a legendarily horrifying incident in which one of the national kilograms was wrested from its casings by a customs agent and exposed to a hostile environment teeming with airborne detritus, not to mention the agent’s organic matter, countries are advised to ship their kilograms in diplomatic pouches.

Dr. Mohr and his colleague Dr. David Newell, who was recently charged with escorting the American kilogram to Sèvres, opted for a backpack and an official Do Not Touch Our Kilogram letter from the National Standards Agency. They made it through, after some harrowing moments.