“Four quiet hours is a resource that I can put to good use. Two slabs of time, each two hours long, might add up to the same four hours, but are not nearly as productive as an unbroken four. If I know that I am going to be interrupted, I can’t concentrate, and if I suspect that I might be interrupted, I can’t do anything at all.” -- Neal Stephenson.
He's unwittingly writing about the hazards of parenthood. I know this, because my life at home has become measured out, not in coffeespoons, but in the attention spans of two human beings under the age of 6. This frustrates my ability to get anything creative done. It's difficult to write, to record songs, to build things... because I wind up feeling so damn distracted.
I found the quotation at the 43Folders discussion of "ultradian rhythms", which seem like a fascinating way of looking at time. It comes on that site because it's relevant to productivity -- getting the most out of your workday, four-hour chunks at a time. But I'm more interested in this as a neurological way of marking the passage of time. Our brains seem to want to divide the day into these four-hour chunks.
Space is marked out relative to the body -- at least, in America it still is. An inch derives (more or less) from a measure called a thumb, which is a component of a foot, which is a component of a yard -- the length of an outstretched arm, measured from the spine. Anything larger than that, and you're measuring in multiples of body parts based on units of land. The yard is an arm, but it's also the space behind your house. These land-units, according to Nigel Pennick, were organized using the same number systems as the runic alphabet. In other words, the measures of the body multiplied by the letters in the alphabet. The words and the flesh.
As I summarized it once elsewhere:
A "northern foot" was also called a "Saxon foot," and was a third-again larger than a "natural foot." In other words, three shafthands made a natural foot, and four shafthands made a Saxon foot. A shafthand was supposedly the width of a hand grasping a spear, I gather.One shafthand was made of three thumbs, which equaled 9 barleycorns. Or, in other words, three threes.
Two northern feet made a northern cubit, or an ell (8 shafthands). ("Ell" is a great word for crossword puzzles, by the way.) Three ells (or 24 shafthands) made a fathom.
Two and a half fathoms (15 northern feet, 20 natural feet) made a rod, 40 rods made a furlong, and 8 furlongs made a mile.
Pennick has these arranged so that there are three levels under the foot, and five levels above the foot -- the smaller measures are all in magic 3s, while the larger are in magic 8s. (Not just the five plus the three, but also by doubling a foot, then doubling that measure, then doubling that measure, etc.)
Time is traditionally measured by the things we can see in the sky -- the sun and the moon. Hours and minutes are more or less arbitrary, based on the visible circle of the horizon, which was measured by the ancient Babylonians in degrees, hours and minutes. The first sundials were models of this division of the horizon, more or less. The Egyptians and the Chinese both divided daylight into 12 sections, but -- importantly -- these sections fluctuated with the speed of the sun. Only during equinoxes would they be 60-minute periods of time.
It wasn't important for them to be that prompt. General guidelines would do.
In Scandinavia, farther from the equator, time was divided like the land into units of eight and three -- eight sections of the horizon, three "daymarks" between midday and midnight. In other words, the day was divided into (eight into 24 equals three) three-hour sections. This ancient division was passed down into the medieval liturgy of the hours, the daily schedule of prayer. There were three hours precisely between Prime, Terce, Sext, None and Vespers (and probably between Lauds and Prime, and Vespers and Compline too). They could (and did) set their comparitively primitive clocks to it.
But because the sun moves at its own pace in summer and winter, I'm betting that during the most productive months, those ancient daymarks were closer to four-hour segments -- the same length of time as those ultradian-related four-hour sleep cycles and Neal Stephenson's four-hour creative units. And during the winter, when most people stayed indoors, the same would apply to the nights... the best time for music and stories. The time to get things done.
Oddly, two days after I wrote this post, this link turned up on reddit.com's front page: http://szabo.best.vwh.net/synch.html
It's about how the simultaneous invention of the hourglass and mechanical clock led to the replacement of serfdom with time-wage labor. In other words, the economic results of breaking time away from the neurological four-hour cycles and into easy-to-regulate 60-minute hours.
A very small number of designs for unique water clocks with sophisticated mechanical parts, including some with regulatory mechanisms similar to an escapement, are known from earlier times in China and the Islamic world. They were marvels that showed off their engineers’ prowess. The East’s clocks were designed and used for no purpose other than mimicking the cosmos in gears. They were nice for esoteric research and entertainment. They were not widely built and thus clocks did not, until developed further by the Europeans, transform human relationships like they did in Europe.
The key engineering breakthrough giving rise to
the mechanical clock was the escapement....
Monks, soldiers, and merchants alike often needed
to arise with an alarm more reliable than the
rooster’s call. Water clocks were expensive to
build and operate. Furthermore, the ringing
alarm sounds better when it is regular. A
compelling case has been made that the
escapement developed out of the regular alarm
ringing mechanism, and fulfilled the need of a
clock that would run overnight unattended and
produce an alarm in the morning, more reliably
and cheaply than a water clock.
Alarm clocks. That's what it was all about.