III. Ordinary Things Essay 13
The Clock Is a Theory
An agreement about time, wearing a face
Look at a clock on the wall. It has a face, two hands, and a number. It is one of the most reassuring objects in a room, and the reason it is reassuring is that it seems to be a fact rather than an arrangement. It is not. Behind the little circle of numbers is a stack of agreements that took a very long time to make, and every one of them is a decision that could have gone another way.
Here is what the clock is doing. The two hands are pointing at a place on the face. The face divides the day into equal pieces. The pieces are numbered. The number eleven means the same thing to the person at the bus stop and the person in the classroom, and it means the same thing in the shop and the kitchen, because they have all agreed to share a grid. Without that agreement, "eleven" would be a local word, and a meeting at eleven would be a meeting somewhere.
A clock does not measure time. Time is not a substance that a dial divides up. A clock is a device for holding a shared agreement in view, and it is one of the most successful agreements humans have ever made, and it is an agreement, and agreements can be examined.
What the clock shows and what it is
At the tangible level, a clock is a small number of things. Two hands, twelve marks, a tick, a battery, a hand to wind it if it is the old kind. You can hold the thing. It is a machine, or a mechanism, and the whole of its physical existence is a few grams of metal and glass. The claim that it is a machine is completely true and completely beside the point, in the same way that the claim that a cup is a ceramic vessel is completely true and completely beside the point when you are trying to know what the cup is for.
At the abstract level, the clock becomes a number, and a very peculiar number. It is not a quantity of anything. You cannot hold eleven o'clock, and you cannot pour it out. What the number actually stands for is a position on a shared grid, and the grid is the abstraction, and the grid only exists because of the agreement. The interesting thing about eleven o'clock is not that it is a number but that it is the same number for everybody. The clock is the physical form of a shared coordinate system, and coordinate systems are inventions.
At the principle level, the clock produces punctuality, or rather it produces the possibility of punctuality. Be on time is a principle in the sense used earlier on this site: an abstraction given authority over action, which tells you what to do in a case you have not met. Nobody meets "be on time" in a case. Nobody can enumerate the situations it covers. It works because the grid makes it checkable, and a principle with no way to be checked is a slogan.
And at the system level, the clock is a node. The moment the school bell rings at eleven is not a fact about the clock. It is a fact about a whole arrangement of rooms, teachers, lesson times, bus timetables, break times, and the order in which those things have to happen. Change any of them and the bell has to move, and it moves everything else with it.
How the grid got made
No one invents a grid of hours in a day. The day is what it is, and it does not come with edges. The edges are put there by people who needed them to line up with each other, and the needs that did the work were mostly commercial rather than scientific.
Railways were the great one. A train that leaves at a time has to arrive at a time, and the passenger who changes trains has to be able to read a timetable, and the timetable only works if the times on the printed page are the times on the clock in the tower, and the clock in the tower has to be the clock in the next town down the line. Local solar time, where noon is when the sun is highest above your own house, is perfectly good on its own and completely useless for a network. Standardising time across the railway network meant agreeing to a single version of noon that is wrong in every place except one. The whole world did this, and did it because the alternative was a timetable that broke.
That is worth noticing as a general shape. The clock face is a piece of local truth surrendered for the sake of a shared schedule, and the surrender was nearly total. Almost every place on earth now uses a time that is measured from somewhere else, chosen so that a train can run on time. The noon you have is somebody else's noon. The agreement was not scientific. It was practical, and then it became so ordinary that nobody can remember it was an agreement at all.
Take a school with a bell that rings at five past nine, and a timetable built around it. The bell is the shared coordinate system. Everything is positioned relative to it: registration, the first lesson, the buses that bring the year nine classes in, the kitchen's first batch of toast, the caretaker's rounds, the time a supply teacher is asked to arrive.
Now the first bus is eight minutes late. Not because of the bus. Because of a road closure that started at half past eight. Eight minutes is nothing. The bus arrives, the class arrives, the register is taken eight minutes late, and the first lesson starts eight minutes late.
Now change the conditions slightly. The school is on a single site, all the buses serve the school, and the timetable has no slack anywhere, because a slack period is a period in which nothing is being taught. Eight minutes of lateness at the start has nowhere to go. It does not vanish. It is absorbed by shortening the first lesson, which is then shortened again by the second teacher who is running late for the same reason, which means the second class also starts late, which means the register for that class is late, which means the form tutor is still in the corridor when the bell for the next lesson goes.
And the interesting part is what happens on the days when nothing goes wrong. The timetable has no slack, so it has no capacity to recover. A good day and a bad day are the same length, and the bad day leaves a mark that gets carried by whoever is downstream. After a few weeks of this, the school is running a timetable that is nominally nine o'clock to three forty-five but is actually a timetable that depends on everything going exactly right.
What the grid hides
A shared grid is enormously useful and it hides things very efficiently. Three of them are worth naming.
It hides the arbitrariness of the origin. Why is it eleven and not ten? Because the clock face is numbered from twelve, and the twelve comes from a number system that was old when clock faces were designed, and which had nothing to do with the number of hours in a day. The face could have been numbered in twenty-four divisions, and proposals to do exactly that were made and not adopted. There is no reason for twelve hours. It is a fossil.
And it hides the fact that a time is a place. When a train timetable says 10:20, it is really saying 10:20 where the train is, and the distance between there and here is a hidden variable. This is why the same clock in two places can disagree, and why the disagreement was worth a war of words in the nineteenth century, and why the resolution was to make the disagreement impossible rather than to settle it.
What if the school moved its start time ten minutes later? The bell moves, and the buses move, and the kitchen moves, and the caretaker's round moves, and the teachers who have childcare arrangements have ten more minutes, and the students who take the early bus have ten more minutes of their morning, and the sports clubs that use the hall have ten fewer. Almost nothing about the teaching changes. Almost everything about the arrangement changes, and the change is invisible right up until the day it is made, at which point everybody is surprised that it was so complicated.
Now change a different condition. What if the school kept its start time and simply let the first lesson be eight minutes shorter on the days when the bus is late? The teaching changes, marginally, and the arrangement does not. It is a better trade in every case except the one where the teacher needed those eight minutes for something specific, and that teacher is the person who has to be asked, which is exactly why the trade cannot be made by the timetable alone.
"Time is a property of the universe and the clock measures it." This is the most natural mistake about the clock, and it is natural because the clock is the most convincing object in the room. A clock does not measure time. There is no quantity of time in the room to measure. What there is, in the room, is a piece of machinery that is very good at displaying a number, and the number means something because of what everybody has agreed.
And the deeper version of the mistake: "punctuality is about being decent to other people." Sometimes it is. Mostly, punctuality is a property of a shared schedule, and it is as much a fact about the arrangement as it is about anybody's character. The person who is reliably late is often the one who is coping with a bus, a shift, a timetable with no slack, or a meeting scheduled for an hour nobody can get to. Sometimes they are inconsiderate. The point is that the two cases look identical from the outside, and only one of them is fixed by asking nicely.
It is worth adding that the person who is reliably late is often also the one who makes the grid work for everybody else. A person who arrives exactly on time has no slack at all in them, and a system that depends on the grid needs somebody who can absorb a minute when the minute needs absorbing. Sometimes that person is a lateness absorber by choice. Nobody thanks them for it.
The loop of lateness
The cascade is a loop, and it has a familiar shape. A delay at the front of a chain with no slack pushes everything back, which makes the people at the back late, which means they start their next thing late, which is now the front of another chain. If the chain feeds back into itself, which it does whenever the same people are in the chain more than once in a day, the lateness starts to compound.
There is a well known habit in offices of saying that a person who arrives late is not being disorganised but is being trapped. Sometimes that is kindness. Sometimes it is an excuse. The system view does not take sides. It asks how many minutes of slack the chain has, where the delay entered, and how much of it the chain can absorb. A chain with slack absorbs small delays and passes on large ones. A chain without slack passes on everything, and a chain with no slack that feeds back on itself turns small delays into large ones.
Limits
The clock is a good model and it is a model. It shows a uniform grid with equal units, and the real day is not like that. Attention, energy, and the difficulty of a task are not uniform across the grid, and a good timetable that treats the grid as uniform will put the hardest thing in the slot where everybody is most tired, which is the slot the grid says is the same as every other slot.
Second limit: agreeing on a grid does not mean agreeing on what the hours are for. Two people can both say they are punctual and mean different things, and the disagreement only shows up when one of them is waiting. The grid resolves the question of when and leaves the question of what entirely open.
Third limit: the clock is a shared fiction that works, and a working fiction tends to hide the costs it has pushed onto whoever cannot use it. The agreement is nearly universal and the people left outside it, working to a different clock, are the ones who are hardest to see.
Stuck
You are stuck at the system level with a clock problem when you can describe the timetable perfectly and cannot change anything. The bell is in the wrong place, the lessons are the wrong length, the break is too short, and the diagram of the day is beautiful and the day goes on exactly as before.
The way out is to change one time and watch what moves. Not to redesign the whole day. Pick the single time that most people complain about, move it by ten minutes, and go and look at the people at the other end of the chain for a week. The complaint is usually not about the ten minutes. It is about the person standing at the end of the chain who absorbs them, and that person is findable, and once found the argument becomes about them rather than about the clock.
Sources
- The general point that railways drove the standardisation of time across the nineteenth century is well established in history. No specific dates, railway company, or named figure are cited here, and any reader wanting them should consult a history of the time.
- The claim that local solar time and standard time differ by a different amount in every place is a straightforward consequence of longitude and is not in dispute.
- All examples here are hypothetical or ordinary operational situations. No specific incidents or studies are cited.