[LEAPSECS] Calendars count days - clocks divide them up

Kevin.Birth at qc.cuny.edu Kevin.Birth at qc.cuny.edu
Tue Jul 2 11:35:54 EDT 2013

The day is panculturally recognized as a time reference, but many cultures
are not concerned with the day as a uniform unit of duration. Instead,
days can vary in length (like months and years), and it is not a problem.

Very few cultures have defined the concept of day both in relationship to
a time reference and a uniform duration.

The definition of a day in terms of multiples of smaller units of time,
e.g., 86400 seconds, is culturally unique and extremely recent. In terms
of human history, the definition of small units of time in relationship to
solar cycles is also relatively recent. Previous to the pendulum, minutes
and seconds were conceived as measures of angle in sidereal time. We are
still in the process of working out the consequences of relating the
precise measure of small durations to the cultural emphasis on the solar

And it seems there is impatience about working through these consequences.
Even within Europe, some communities rejected mean time in favor of
canonical hours until the early 20th century. The Gregorian calendar
reforms are still not globally accepted after over 400 years.


Kevin K. Birth, Professor
Department of Anthropology
Queens College, City University of New York
65-30 Kissena Boulevard
Flushing, NY 11367
telephone: 718/997-5518

"We may live longer but we may be subject to peculiar contagion and
spiritual torpor or illiteracies of the imagination" --Wilson Harris

"Tempus est mundi instabilis motus, rerumque labentium cursus." --Hrabanus

Rob Seaman <seaman at noao.edu>
Sent by: <leapsecs-bounces at leapsecond.com>
07/02/13 10:38 AM
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[LEAPSECS] Calendars count days - clocks divide them up

Warner Losh wrote:

>> It is gratifying to see how flawlessly this standard is implemented,

>> despite over 40 years of it being the standard. I guess the far older

>> expectation that every minute has 60 seconds is kinda deeply



> Wikipedia drily notes that "Between 1000 (when al-Biruni used seconds)


> 1960 the second was defined as 1/86,400 of a mean solar day". That 1960

> endpoint to which it refers is the transition to the ephemeris second.

> Rubber-seconds UTC, which has occasional minutes with !=60 seconds,

> comes along in 1961. So we've got around 960 years of the second only

> being a subdivision of the minute, versus 53 years or so of seconds

> being more complicated than that.


> -zefram

Standards aren't just randomly chosen, they express an underlying model of
how the universe works. Implicit in the standards expressing, say, units
of electric current and resistance are observations and inferences with
names like "Ohm's Law". The proposed new formalism for the SI (metric)
system relies on this explicitly:



The conceptual model underlying the SI-second is frequency. Civil
timekeeping simply represents another standard. Conceptual models fail if
an attempt is made to force fit them together.

Speaking of frequency, consider the words that people use:


(This is American English - statistics for other languages would be
welcome.) The ranks and frequencies of usage of words related to

54 year (n)
90 day (n)
188 week (n)
237 month (n)
273 hour (n)
309 minute (n)
683 second (n)

The word "day" is used more than seven times as frequently as the word
"second" (as a noun). The three calendar words (year/month/day) are more
prevalent than the three clock words (hour/minute/second) by greater than
four to one. Even "century" is used more frequently than "second", and
"decade" is used almost as frequently:

606 century (n) 65667
731 decade (n)

Whatever underlying model of human cognition, these data cannot be used to
argue that our parsing of time into units of days is irrelevant to
society. "Day" is more frequently used than key nouns like man, woman and
child. The noun "second" is less frequently used than other words
descriptive of days like morning and night - and the combined usage of the
terms AM and PM is 50% more frequent than "second".

In fact while all the words above are nouns the rankings are listed for
all parts of speech. If you scroll down the very long list you will find
that the top five most frequently used nouns themselves are:


People perceive time
in a way that descends from
a year and a day


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