*Post by gerson*... King's Chamber ...

... height exactly half the floor diagonal ...

But I'm not so impressed that the length, to 1 part in a thousand, is

sqrt(160) megalithic yards

I thought of the floor diagonal as being sqrt(200), but of course it's

better expressed as 10*sqrt(2) now that you sort of point it out, and

the other dimensions follow, that is the sqrt(160) and so on. The floor

diagonal is the same as the diagonal of a square of side 10 My.

I'm pleased you were interested enough to make a post. (I wish

you were more interested though, or everyone really).

I think the trouble is that people think (rightly, perhaps?) that you

have stumbled on a coincidence and ascribed undue significance to it.

A human-friendly measure of distance (for the purposes of, say, deciding

how long a wall should be) is likely to be somewhere between the length

of a shoe and the distance between maximally outstretched hands. Call it

300mm to 2000mm, say.

Consider a number of building projects across the globe, all taking part

at roughly the same time, all in places that have all /independently/

devised their own standard of mensuration. Let us assume that each of

them has adopted a standard distance at random within that range, and

that their standard measure has been made to a tolerance of +/- 1mm

(which would be extraordinarily good for the time, I think).

How many such (independent!) projects must there be, before there is a

50% chance that at least two of them are using the same measure?

There are 1700 choices, so you might think there would have to be 850

such projects for there to be a 50/50 chance that two will use the same

measure purely by chance.

But no. This is an example of the Birthday Paradox, and the answer turns

out to be not 850, but a mere 49. And 89 will give you a 90% chance! In

fact, 152 such projects will give a 99.9% chance of a coincidence. How

many building projects were actually going on at the time? Thousands, I

should think.

So, when two disparate cultures are using what appears to be the same

unit of measurement, the burden of proof lies with those who think it is

/not/ a coincidence; it is up to them to show a causal connection.

--

Richard Heathfield

Email: rjh at cpax dot org dot uk

"Usenet is a strange place" - dmr 29 July 1999

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