Why do we still have a seven-day week?

December 11, 2008 10:53 AM

What if we made a "week" 10 days long?

So, doing some thinking this morning (in the shower, natch), and my mind wandered... The basis for the length of a day, month, and year are astronomical, but the week is a purely human construct (setting aside the Biblical basis of seven days of creation). There doesn't seem to be a good reason (other than tradition) as to why people haven't changed the number of days in a week. Is tradition the only reason why, or has society developed around it some overwhelming reason to keep the seven day week? I know there have been different calendars used in the past (French Republican Calendar comes to mind); why didn't they stick?

What benefits and defects would accrue to "society" if it were decided that the length of a week should be longer or shorter than it currently is? Can anyone think of any reasons why some group of folks would want to do something like this? What would be the optimum length of the week, if it's determined to not be seven days?

posted by jasondbarr to Society & Culture (33 answers total)

Phases of the moon, dude.
posted by rokusan at 11:02 AM on December 11, 2008 [3 favorites]

I would say because four seven-day weeks fit pretty well into a lunar month.
posted by dunkadunc at 11:03 AM on December 11, 2008

Two words: The Pill. Major societal shift if that system had to change.
posted by girlmightlive at 11:14 AM on December 11, 2008

The Mayans knew all about solar and lunar cycles but didn't have a 7-day week.

So thats one strong argument that 7 does not arise naturally from astronomical considerations. Their calendar has 13-day and 20-day units. They knew that the lunar month was 29.5 days long but for them that was just another calendar along the main calendar. Still no need for 7-day weeks.
posted by vacapinta at 11:15 AM on December 11, 2008

Wikipedia
posted by neroli at 11:18 AM on December 11, 2008

All measurements of time are human constructs. Is that too pedantic? Some of them have been constructed to coincide with astronomical events, sure. I think months are way more screwy.
posted by peep at 11:19 AM on December 11, 2008

Well changing this would be extraordinarily expensive. Plus, unless the whole world switched at once it would be very inconvenient to do business internationally.

The only benefit I can think of is when you say "80 days from now" you can easily calculate what day of the week that will be.

Having 7 days is about the limit to how much stuff people can easily fit in their heads at once; a longer week may be more difficult for people to plan out.
posted by aubilenon at 11:22 AM on December 11, 2008

There have been attempts to institute decimal weeks -- the French Revolution was the most famous, I think. Here is a page about decimal time; googling "decimal time" will get you a lot more.
posted by Forktine at 11:27 AM on December 11, 2008

Best answer: No one knows why we have seven day weeks. It was probably useful very early on to have a cycle longer than a day, but shorter than a lunar month. Seven fits "okay" but four would have fit just as well and five or six would have fit better. Explanations for seven have been tossed about such as: phases of the moon, the seven celestial "planets" (Moon, Mars, Mercury, Jupiter, Venus, Saturn, Sun), geometry, etc.

The Egyptians used a 10-day cycle and the Mayans used 13 days. The Romans used an 8-day market week.

If you have something like a market day, where farmers, fishers, bakers, etc, bring their goods to market on a recurring day, it's important everyone show up on the same day or your economy breaks.

The 7-day week cycle has not been interrupted for recorded history. Even when the calendar has been changed, such as from the Gregorian to the Julian, it was done in such a way that the pattern didn't break, for at least the past 2000 years.

So it seems likely that a) people have a definite need for a multi-day cycle shorter than a month; b) once it takes hold, it becomes highly resistant to change; c) when two cycles competed, the one with backed by the larger or economically powerful culture would eventually win out.
posted by justkevin at 11:27 AM on December 11, 2008

There doesn't seem to be a good reason (other than tradition) as to why people haven't changed the number of days in a week

And on the SEVENTH day, he rested.


I'm guessing seven days feels "about right", anymore and the human mind tends to forget things too easily or the mental feeling of the passage of time "feels" too long. I imagine if we went any longer, work productivity would suffer and depression would be become more prevalent. People need a break and the optimal time seems around 5 or six days.
posted by Brandon Blatcher at 11:31 AM on December 11, 2008 [2 favorites]

Religion is another reason. For some religions (christian, jewish) every 7th day is a day of rest. For a society of Christians, a seven day week just works.
posted by Gor-ella at 11:35 AM on December 11, 2008

Here in the U.S., we can't even get on the metric system.
posted by mkultra at 11:42 AM on December 11, 2008 [5 favorites]

Best answer: I think the 5:2 ratio of working days to rest days is just about right.

5:2 = 260 working days a year.
6:4 = 219 working days a year, employers would not tolerate the loss of 41 working days a year.
7:3 = 255.5 working days a year, but employees wouldn't tolerate a 7 day working week.

Alternatively you could go for two miniweekends a week, with a 4-1-4-1 pattern, however 1-day weekends would not be tolerated by employees (not enough time to relax/take trips over the weekend) - plus with an 8:2 ratio they get significantly less rest days over a year (292 working days/year). A 3-2-3-2 pattern wouldn't work for the same reason as a 6:4 week.

A 4-2-3-1 (or 4-1-3-2 but the first one has better balance) pattern seems the best compromise between working week length and total yearly work days, but having an asymmetrical pattern throws up a lot of difficulties and would be a lot harder for people to get used to/to implement in calendars, computers, etc.
posted by EndsOfInvention at 11:54 AM on December 11, 2008

There was a 13-month, 28-day month calendar proposed once that I remember liking. That gives you 364 days. Every month started on a Monday and ended on a Sunday. You always knew that January 13 was a Saturday, and June 3 was a Wednesday. Always.

"New Year's Day" was simply not counted: Sunday Dec 28, New Year's Day, Monday Jan 1.

Same trick for "Leap Day" when needed.

But even this still had seven day weeks.
posted by rokusan at 12:06 PM on December 11, 2008

Because naming rights would undoubtedly be sold to the highest bidder. Who wants to have their birthday on FedExtraday, or get married on AT&T Presents The Day Between Tuesday and Wednesday?
posted by Ookseer at 12:06 PM on December 11, 2008 [23 favorites]

if somebody wouldve thought to make it 4 days of work & 3 days off or 6:4, 2000 years ago we would all be living alot better now.
posted by fumbducker at 12:52 PM on December 11, 2008 [1 favorite]

setting aside the Biblical basis of seven days of creation

Err... the seven day tradition is older than the oral tradition that became the biblical creation myth.

Seven days = the seven heavenly objects that are viewable from Earth with the naked eye.

The ancients weren't dummies (but they did get it wrong some,) they were careful observers, and to them these mysterious seven objects appeared to drive cyclic events here on Earth.

The waxing and waning of the moon, the ebb and flow of the tides, the seasonal changes observable by humans living in high latitudes, day and night - it all seemed interconnected (and some of it is.)

For them not to craft their time around objects in the night sky would have been stranger, and I think the seven day week, with it's reliance on the sun, moon, and five visible planets, is a elegant, if somewhat anarchistic foundation for our earthly weeks.

That the seven day week has pretty much been the de juor for many thousands of years is a testament to the longevity of certain nature-inspired human constructs.

We can't be sure of the future, but I'm willing to bet that even thousands of years from now, humans living on earth will still divide their time in this way.
posted by wfrgms at 12:56 PM on December 11, 2008

the 5:2 ratio of working days to rest days is just about right.

Excuse me, but the five day work week, TGIF, and Sunday night football are all very modern inventions.

People living even just a few centuries ago wouldn't know what the hell a weekend was, let alone those living with a seven day week for the many thousands of years before some lot decided that the seventh day (or is it the first?) should be a day of rest...
posted by wfrgms at 1:00 PM on December 11, 2008

Response by poster: Err... the seven day tradition is older than the oral tradition that became the biblical creation myth.

Out of curiousity, how do you validate this claim that a seven day week is older than an oral tradition of a creation myth? I would guess that oral traditions of a creation myth would have arisen prior to calendars or the need to differentiate between days, since every day was a scramble for survival and one was just the same as the next. That's pure conjecture on my part, but I'm curious as to your sources.

Anyway, thanks for all the great comments, folks. Appreciate it!
posted by jasondbarr at 1:02 PM on December 11, 2008

I don't know about now but 20 years ago in Korea, Saturday was a workday. I would bet that's the case in a bunch of places.
posted by bonobothegreat at 1:03 PM on December 11, 2008

I don't understand why the lunar cycle should be dismissed out of hand:

New
1/4
Full
3/4

.. seems perfectly reasonable way to divide up the lunar month. If that, then what? Seven 4 day weeks? I suppose a 14 day week could work but maybe the powers that be don't want people away from church that long.
posted by bonobothegreat at 1:14 PM on December 11, 2008

how do you validate this claim that a seven day week is older than an oral tradition of a creation myth?

You spoke in terms of the biblical creation myth. Most scholars think that the story of Genesis with it's seven day creation was cobbled together into it's current from around 400 BCE. Obvious the story owes its existence to older oral traditions going back much further - some estimates put it as far back as 1000 BCE with 2000 BCE being an outlier. (By comparison many scholars date the Iliad to 800 or 900 BCE with oral traditions going back at least to 1000 BCE and further. The Iliad being a much more complex and nuanced story - even contemporary - than anything found in the Old Testament.)

Despite this, the seven day week as a concept is older still. Some scholarship points to the concept of a seven day week as originating (or at least existing) in ancient Babylonia during the middle bronze age from the 15th to 20th century BCE.

The fact that the days of the week take their names from pre-Christian (not to mention pre-Hebrew) deities should be yet another indicator that the concept of the week, or days of the week, pre-dates biblical theology.

This line of inquiry actually exposes a deeper problem in monotheism, in that so much of the monotheistic cannon borrows heavily from polytheistic history. In this light the monotheistic creation myth as handed down in Genesis seems to not only plagiarize the seven days, but to co-opt them into a new tradition. This must have been appealing for early Jews and Christians as it allowed them to keep the same schedule while offering a monotheistic raison d'être for the seven day week while ignoring it's obvious pagan roots.
posted by wfrgms at 2:38 PM on December 11, 2008 [3 favorites]

it's = its in the above. Ugh... too many lunch time beers.
posted by wfrgms at 2:41 PM on December 11, 2008

guess that oral traditions of a creation myth would have arisen prior to calendars or the need to differentiate between days, since every day was a scramble for survival and one was just the same as the next.

It's debatable. Sort of a chicken and egg type question. Obviously early agriculture requires a precise understanding of where you are temporally in the year. The calendar, with it's ties to astronomy, probably came about as soon as the first settled communities formed.

We know that sophisticated urban cultures existed in Mesopotamia around 5000 BCE, so the concept of a astronomical calendar is at least that old and probably as old as the oldest settlements so about 10,000 BCE. Again, since the seven days are astronomical in origin, we can assume that they too are very old.

But do they pre-date any and all creation myths?

We have fragments of the Sumerian creation myth dating from about the 19th century BCE which includes a flood myth - flood being de jure when your early high output farming requires living in proximity to a river delta. The oral tradition obviously goes back further.

The fact is you don't get good story telling until groups of people settle down and are able to produce agricultural surplus. Without that surplus, it's impossible to support the witch doctors and sages who hand down their best guesses as myths. You get agricultural surplus by understanding the cyclic nature of the seasons and you understand that by paying attention to the location of the objects in the sky year round, year after year.

Creation myths all share a common "after the fact" thread in that they all attempt to explain pre-existing observations. Therefore these pre-existing observations (i.e. that there seven objects that seem to move around the earth and when they are in the same place again, one year has gone by and now it's time to sow or reep...) would seem to predate the creation myths which attempt to explain them.

In short: sophisticated creation myths seem to be a side effect of studying the natural cycles that allow for human settlement.
posted by wfrgms at 3:10 PM on December 11, 2008

I say we leave the seven day week alone and scrap the months. What have the phases of the moon ever done for us?
posted by flabdablet at 3:59 PM on December 11, 2008 [1 favorite]

wfrgms, do you have a cite on the "you don't get good story telling until groups of people settle down and are able to produce agricultural surplus. Without that surplus, it's impossible to support the witch doctors and sages who hand down their best guesses as myths" thing? I can't tell if you're arguing that leisure is necessary for mythmaking (isn't it debatable whether members of agricultural societies have more leisure time than members of pre-agricultural ones?), or if you're specifically saying that class stratification is required.
posted by You Can't Tip a Buick at 4:02 PM on December 11, 2008

I met several people in Ukraine whose work schedules were not week-based. One was a guard/doorman at an apartment building: 24 hours on the job, then 48 hours off (a brutal schedule, to be sure). Another was a nurse whose work was scheduled in blocks of 10 days. It worked OK, but the cycle-length mismatch with everybody else's life caused difficulties.
posted by eritain at 5:34 PM on December 11, 2008

I can't tell if you're arguing that leisure is necessary for mythmaking

Class stratification is certainly required and demarcates the difference between early hunter-gather societies where all human output was directed toward basic survival and those where an economic surplus allowed for specialization in second tier output not associated directly with food production. This allows for the rise of the priest class whose knowledge of the cyclic natural world goes together nicely with early agriculture - which I guess is connected with food production. Natch.

Anyway, the point is that the elaborate myths such as Genesis are the product of post-agrarian, settled societies relying on crude astronomy (and other innovations) to provide agricultural surplus, and the assurance that the world is ordered and somewhat predictable. As such concepts such as the seven day week likely predates more contemporary biblical stories by many thousands of years...

I'm far too lazy to cite anything specific, I'm pulling all of this from various anth classes, etc.
posted by wfrgms at 5:53 PM on December 11, 2008

I say we leave the seven day week alone and scrap the months. What have the phases of the moon ever done for us?

Birthdays! No fun to say, "my birthday is day 267" or "week 13".
Months let us pretend we're more special.
posted by changeling at 5:55 PM on December 11, 2008

France had a 10-day week after the French Revolution: see wikipedia. Less religious, also less popular: "The calendar was abolished because having a ten-day working week gave workers less rest (one day off every ten instead of one day off every seven). . ."
posted by betterton at 7:30 PM on December 11, 2008

Best answer: The seven day week existed in Rome before Christianity, because of Persian influences through Mithraism (branching from Zoroastrianism), whose military cult was widespread among Roman nobles (same goes for horoscopes). Mithraism was based on planetary and star worship, which at the time named 7 orbital bodies, Saturn, Sun, Moon, Mars, Mercury, Jupiter, Venus. Christianity and Mithraism shared common pagan origins to Osiris, so Christian fathers were interested to collapse Mithraism into itself to avoid the confusion of similarities between the two religions (both are forms of cereal grain sacramental rebirth dating back to the invention of agriculture, Christian ritual mostly Greek, but Dionysian-inspired Christianity having the advantage of a human messiah imported from Judea).

To culturally distinguish itself from the Jewish sabbath, the 7-day week was officially declared by Constantine in 321, beginning on Sunday as rest, which was the main day for Mithra, a sun god. Constantine was a man who worshiped Sol Invictus, through Mithra, but who also converted Christianity as they knew it to become an acceptable public form of previous Mithra worship for the nobles (who firmly belonged by oath to an elite brotherhood and soldier's cult, which was completely closed to women and slaves.)

The 7-day week no doubt originated prehistorically with lunar time keeping, since the crescents, full and new moon were quartered 7.3 days apart. I would suggest keeping it and replacing the arbitrary months instead, with four seasonal units of 91 days, which divide by 7 (as 13 weeks) and leave an extra day for a new year day by itself, which handles the leap year without adding days to a month. In this way a certain day of a season will always fall on the same day of the week.
posted by Brian B. at 8:50 PM on December 11, 2008 [2 favorites]

Jinx.
posted by flabdablet at 3:45 AM on December 12, 2008

Hmmm... four seasons doesn't really work for Australia. I know. Let's scrap the seasons, keep the weeks, make all the months exactly four weeks long, keep the existing names for the first twelve, add the month of Festivary between December and January, and add one or two days - Yearday and Leapday - between Holiday and January to make everything fit. We could make Yearday and Leapday universal public holidays to help the bean counters pretend they don't exist. Oh, and clearly the weeks should start on Monday, not Sunday. Weekends aren't bookends.
posted by flabdablet at 3:56 AM on December 12, 2008