On Thu, 11 Oct 2018 at 13:04, Steve Allen <sla@ucolick.org> wrote:
On Thu 2018-10-11T12:12:21-0400 Tim Parenti hath writ:
> On Thu, 11 Oct 2018 at 10:49, Paul Eggert <eggert@cs.ucla.edu> wrote:
>
> > To my mind this is more a localization preference than an independent time
> > zone.
>
>
> …which, again, is why I suggested specifying that tz starts numbering the
> hours from midnight.

"midnight" has no meaning at South Pole station, nor on the ISS, and
very little meaning at McMurdo other than how tired the supply crews
from Christchurch are likely to be.

That is a reasonable argument, though a bit imprecise.  "Solar midnight" certainly has no meaning in those places, nor have I argued that it does.
 
At those places the hour 00
designates when the calendar day and date change.

The concept of midnight is itself a localization of us temperate zone
folks,

This is the more salient point, I think.  The folks in the places you mentioned may (or may not) bring their more temperate cultural notions of "midnight" with them to some extent, mainly with respect to communications with home bases, but that's more "imported" than anything truly localized to where they actually are.

See also: Tourists to the Arctic amazed to "see the sun up at midnight" in the summer.  It seems to be an absurd statement on its face, but it's not technically wrong, per se… at least, from their cultural frame-of-reference.
 
and the word "midnight" has no place in tz other than in a
footnote explaining the origin of the simplifications codified in the
underlying tz model of time and date.

I suppose I could argue that the patch I originally proposed in https://mm.icann.org/pipermail/tz/2018-October/026942.html is effectively such a footnote (one that aims to limit tz's scope) — but an alternative, more permissive, approach could certainly be taken to instead remove the other main mention of "midnight" where instead "start/end of calendar day" is more appropriate (likewise replacing "noon" with "midday").

Proposed alternate patch attached.  The general concept of "midnight" in the wall-clock sense is, however, sufficiently commonly understood that it need not be eradicated from the (highly localized) commentary throughout.

--
Tim Parenti