Rob Seaman scripsit:

> >This is like the "day is light and night is dark" statement: there
> >is, at any given location, one and only one sunrise per (solar)
> >day, no matter what clocks say.
>
> Communication prospers when people's clear meaning is not subjugated
> to petty grammarians.

My point was that your rhetorical flourishes have run away with you
on more than one occasion.

> We are now - and have been - discussing timekeeping changes that call
> into question the definition of a "day".  Those of us who support
> solar time are fundamentally asserting the primacy of the the
> standard day over the standard second (for civil timekeeping
> purposes).  Those of us who consider solar time to be a curious
> anachronism, assert the the SI second over the concept of a day (for
> civil timekeeping purposes).

I agree with this assessment, more or less.

> >As I've pointed out before, future times in legal documents are
> >defined as LCT for a particular place, since the future mapping
> >between LCT and any other time scale is not known.
>
> At the risk of igniting a new round of "stage two" nonsense, consider
> the implications of your statement.  Currently LCT (as you appear to
> mean it) is standard time.  Daylight saving (under whatever name) is
> merely an overlay on standard time.  Standard time has no jumps
> (except for leap seconds).
>
> Under your suggestion, LCT would include the jumps for daylight
> saving time (if locally used) as well as the jumps to correct for the
> cumulative effect of tidal slowing.  As I hope I have established,
> these are "fall back" discontinuities that would result in the same
> hour of LCT occurring twice.  Is this not perceived to be a problem?

Perhaps the problem here *is* merely semantic.  By LCT I mean legal
time, the time that de jure or de facto is observed in any given place
(New York time in New York, Podunk time in Podunk, and Squeedunk time
in Squeedunk).  That includes all periodic or secular changes.
And although periodic changes are far more common, secular changes
for reasons of public convenience are *far* from unknown.

I will try to say "legal time" from now on, though there are parts of
the world (Antarctica, the oceans) where there is no legal time
strictly speaking, and de facto time rules.

It *is* a problem that some instants of (TAI/UTC) time have the same
LCT labels in certain time zones.  But it's a problem that we already
deal with once a year.  TV stations, for example, normally broadcast
the same program twice in a row on Leapback Sunday, at least in the U.S.

--
John Cowan  [EMAIL PROTECTED]  www.ccil.org/~cowan  www.reutershealth.com
The penguin geeks is happy / As under the waves they lark
The closed-source geeks ain't happy / They sad cause they in the dark
But geeks in the dark is lucky / They in for a worser treat
One day when the Borg go belly-up / Guess who wind up on the street.

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