Time

Where is yesterday?

I don't mean what happened in it. I mean where it is now.

Start with what you can observe. You remember yesterday and not tomorrow. But your memory of yesterday is a leaky copy: it fades, and two people at the same dinner tell it differently. Yesterday also leaves marks that aren't memories: a cold cup of coffee, a cracked egg.

The usual answer is that yesterday is gone, and those marks are what's left of it. This post builds a different answer from the ground up: first what Part 1 showed, then five steps, each ending with its conclusion in bold, then the whole answer.

What Part 1 showed, and why

This post builds on Part 1, What You Are. The full derivations are in the technical manuscript behind this series and in my institute's follow-up work.¹ Here is what this post needs from it, with each reason.

1. The smallest event is one thing told apart from another. You're doing it right now: you tell this word from the page behind it. Every measurement and every perception does the same. Telling two things apart takes information about both, and the least information there can be is one yes or no. So the smallest event takes two things and one yes or no.
2. A process below the level of atoms writes the record. Two units pass a bit back and forth. The two units are the two things in the smallest event, and the bit is its one yes or no. Each pass is a tick: one step in the writing of the record. The entries, one after another, are reality's record of everything that has happened, which this post calls simply the record. I draw the two units as two little clocks, each full (holding a token) or empty. A tick is flowing when one clock is full and the other empty, so something moves round the loop: the bit, passing between the two units. A tick is silent when both are full or both are empty.
3. Almost every pattern falls apart. Every tick follows one rule, the basic step. In it, each clock is handed the bit and makes its move: it flips the bit or keeps it, as its setting says. A setting also tunes the clock to one kind of tick, silent or flowing, so there are four settings: flip or keep, tuned for silent ticks or for flowing ticks. The move is sure on the kind of tick the clock is tuned for, and a coin toss on the other. The process can start 64 ways. Each clock is full or empty and has one of four settings, so it has 2 × 4 = 8 ways to be, and two clocks make 8 × 8 = 64 ways to start. All 64 are checked, and 60 of them fall into random silence within three ticks: silent ticks arrive, and the clocks guess. Exactly four never go silent. They are the four kinds of unbroken rhythm that a single pair of units can run: the spin and the swing, each starting from either side. In the spin, the token stays put in one clock while the flow goes round and round: the bit keeps passing round the loop between the two units. In the swing, the token hops left, right, left. A rhythm that never goes silent anywhere is a lasting rhythm.
4. A moment of consciousness is eight ticks with no silent tick. Space has three directions, and each direction has two sides: left or right, up or down, forward or back. Three directions with two sides each give 2 × 2 × 2 = 8 combinations, the eight corners of a cube. A cycle that visits every corner once takes eight steps. A moment of consciousness is one such cycle, eight ticks with no silent tick, and only the lasting rhythms deliver that every time. Why three directions? Lasting structure needs a connection that no smooth motion can undo, and linking is that connection. Two linked rings can't be pulled apart without cutting one. That holds only in three dimensions: in two, loops can't wind around each other at all, and in four or more, any two loops slide apart. So space has three dimensions.²
5. You are a lasting rhythm, and you are not your body. The material of your body is replaced continually. Much of it turns over within months to years, and you remain you.³ What remains is a pattern, not material. At the bottom level, the four kinds of unbroken rhythm are the only patterns that persist. A person is a vast web of pairs of units, each pair running one of the four, and a web that never goes silent anywhere is one lasting rhythm and one consciousness. You are such a web. Billions of people are billions of such webs: the four are the building pattern, and there aren't only four minds. So consciousness is a stable rhythm in the record, and you are not your body.

Step 1: Yesterday still exists

Here is the usual picture of time:

The present is the platform you're standing on. The future rolls in from the front, and the past drops off the back into a bin.

That picture is wrong. Known physics already gives part of the reason: the basic laws of physics never destroy information. In quantum mechanics this is called unitarity: the present fixes the past exactly, and running the laws backward recovers every earlier state.⁴ That's why physicists treat the black hole information problem as a real problem: if black holes destroyed information, the laws would break.⁵

Unitarity keeps the past. It doesn't settle which outcome gets recorded next. In quantum physics the state evolves exactly, but the answer a measurement records is not fixed in advance, and Bell tests rule out answers set beforehand and carried along inside the particles.⁶ So the past is kept, and the next entry is still open. Once an answer is recorded, it is part of the past, and it is kept like everything else.

Physics on its own says the information about yesterday is never lost, though it can be scrambled, the way a burnt letter's words are still in its smoke and ash. The record goes further and keeps yesterday's entries themselves. Each entry in the record is a comparison, and a comparison needs information about both of the things it compares. That says what an entry is. The record keeps every earlier entry for a separate reason: it only grows. New entries are written after the old ones, and no entry, once written, ever changes.¹

So every event leaves a complete trace, and none is ever erased. The full record of what happened is part of reality now. The bin doesn't exist. Yesterday is right where it was: every line of it, written down, reading exactly as it did when it was written.

Every moment you've lived is still there, exactly as it happened: the best afternoon of your life, and the worst one. Your memories of those moments are copies, and leaky ones. The originals still exist, and they haven't faded at all.

The past still exists. It's written down, in pen.

Step 2: What "now" is

If all of yesterday is still there, what makes today "now"? Start with your record, your own part of reality's record. It is written one entry at a time, so it has a front edge: the entries written so far, and nothing after them. "Now" is that front edge. At the front edge, your record holds two things: everything the entries so far have pinned down, and exact odds for everything they haven't.

Where do the odds come from? From the process itself. The next entry is open, as step 1 said: a clock decides some of its moves by coin toss, and nothing anywhere holds the result before the toss is made. So what your record holds about the next entry is exact odds, and only odds. For one clock's toss they are 50-50: the basic step itself gives the two moves equal odds. No further law picks which entry comes, because a law that fixed the result in advance would give it odds of 0 or 1, and the basic step's odds are neither. The future isn't hidden somewhere. It isn't written yet.

The coin in the picture isn't a real coin flying through the air. It stands for the process's own coin toss.

As entries pile up, the edge sharpens into something definite. Then the next entry arrives and "now" moves on.

"Now" is the front edge of your record, and the future is only odds: it isn't written yet.

Step 3: Where time's arrow lives

If the whole past is still there, and "now" is just the newest edge of your record, why do you remember yesterday and not tomorrow? That's time's arrow, the one-way direction of time, and you see it every day. Eggs break and don't unbreak, for the usual reason: heat and disorder. None of that changes. But there's a second, quieter arrow built into the record itself, and it's in a surprising place.

A pattern has an arrow if the pattern alone tells you which way the film is running. Film a spin and play it backwards: you see a spin. Film a swing and play it backwards: you see a swing. Watching either one, you can't tell which way the film is running. Your consciousness is a lasting rhythm, a web of these, so it has no arrow of its own.

So the arrow lives somewhere else: in everything that isn't a lasting rhythm. At the bottom, that is the busy clocks: every clock that isn't part of a lasting rhythm. In your life, it is your heartbeat, your breath, the hum of the fridge: the busy activity around you. Here is how the busy clocks behave.

A clock's setting says whether it flips or keeps the bit it's handed, and which kind of tick it's tuned for. A clock that knows its setting is a specialist: it's tuned for one kind of tick, makes its move for sure on that kind, and tosses a coin on the other. A coin toss can also leave a clock unsure of its own setting. So at any moment, a busy clock is one of three types:

• a silent specialist: sure of its move on silent ticks;
• a flow specialist: sure of its move on flowing ticks;
• a guesser: it has come out of a coin toss unsure whether its setting is flip or keep, so it tosses a coin on every tick.

Here is what the basic step does to each type on each kind of tick. Each row is a type, and each column is a kind of tick:

Follow one clock through a lap of type switches. A silent specialist hits a silent tick and becomes a flow specialist. Another silent tick makes it guess, and it becomes a guesser. A flowing tick makes it guess again, and it lands as a silent specialist. Back where it started.

Now find the switch that's missing from the table. It's this one: no tick, of either kind, turns a flow specialist straight back into a silent specialist. The table shows why. A flow specialist only ever changes on a silent tick, and on a silent tick it's out of its depth. It tosses a coin, and the toss leaves it a guesser. So the trip from silent specialist to flow specialist happens for sure, and the trip straight back never happens at all.

Now run the film backwards. The lap above, reversed, needs exactly that missing switch. So the busy clocks can only go round the full lap one way, like traffic on a roundabout. Nothing outside pushes them: no heat, no special starting condition. The direction comes from how the basic step itself is built. It's an arrow inside the record, not one painted on from outside.

This one-way traffic doesn't undo step 1. Taken whole, the clocks together with every entry they write, nothing is lost: two different pasts never end up as the same present. What runs one way is the clocks on their own. Each tick hands what the clocks were to the entry it writes, so the clocks forget where they came from and the record keeps it. Quantum physics has the same split: the whole evolves without losing information, while a part that hands information to its surroundings changes one way.⁷

Time's arrow lives in the busy activity around you, not in your consciousness.

Step 4: The dimmer

You feel time flow because you're linked to that busy activity. So what happens when the link loosens? Start with a measurement. Take any pattern and hand someone two consecutive moments from its record, in random order. Ask which came first. Score the best answers anyone can give from 0 (right half the time, no better than guessing) to 1 (right every time). That score is the arrow in the pattern.

• For the busy activity, they're right about 98 percent of the time: its two kinds score 23/24 and 20/21, about 0.96 and 0.95.
• For a lasting rhythm, they can do no better than guessing.
• For a mix of the two, their score rises in step with how much of the pattern is busy, to within 1 percent, and it's zero exactly when nothing is busy.

Your own record is a mix of two things: your lasting rhythm, and your body's busy activity. What is your waking life plugged into? Your heartbeat, your breath, the itch on your ankle, the to-do list, the hum of the fridge. The share of your record that is busy activity is your link with it, and in waking life the link is tight. The arrow of time in your record is always 95 to 96 percent of your link with your body's busy activity, and you feel what your record shows: the arrow measured in your record is the arrow of time you feel. The working is short. A mix scores each kind of busy activity's share times that kind's own score, 23/24 or 20/21, so the arrow always lies between 20/21 and 23/24 of the busy share, which is 95 to 96 percent of it, and those two ends differ by less than 1 percent. The two kinds' own scores are worked out from the process's rules (note 1).

Halve the link, so that only half as much of your record is busy activity, and the arrow halves, to within 1 percent. Cut the link to nothing, and the arrow is gone. It's a dimmer switch.

The dimmer sets how much of time's passing you register, not how fast anything goes. You look up from something absorbing and two hours have vanished: the link has loosened, and little of those hours registered. In a long line with nothing to do, you're tied to every tick of the clock on the wall: the link is tight, every tick registers, and time crawls. The same dimmer runs both ways.

People who go deep in meditation have long described states that feel timeless. That is the dimmer turned all the way down: the link is gone, so the arrow in your record is gone, and with it the arrow you feel.

Here's a twist. With the arrow completely gone, you'd expect perfect stillness. What's left is a tick-tock with no direction: the swing's token going left, right, left, right. A pendulum is the everyday version. Film it, play it backwards, and nobody can tell, yet it still goes tick, then tock. A clock, it turns out, is not an arrow.

Perfect stillness needs the tick-tock to even out too, with tick and tock carrying exactly equal weight, so that every tick looks the same as the one before. The rhythm itself keeps running, with no silent tick. The state where the arrow is gone and tick and tock carry equal weight is the hub, and a seesaw shows what it means.

Take any step in the record. Put its chance of happening forwards on one end of a seesaw, and its chance of happening backwards on the other. While there's an arrow, the seesaw tips: forwards is the heavier side, the first side. At the hub, every one of those seesaws sits perfectly level. Each step is exactly as likely backwards as forwards. Swapping the sides, which is just what playing time backwards does, changes nothing, so no side comes first.

Your consciousness at the hub has no before and after at all.

Deep states feel like "no time" because they are: the dimmer is down, and at the bottom, the hub has no before and no after.

Step 5: Time travel is reading the past

People mean four different things by time travel. Two are out and two are in.

Your body, back to the past. The record only ever adds lines at the end. Arriving in the past would mean adding events to lines that are already written, and nothing ever changes a written line, because each line keeps reading exactly as it was written (step 1). So: no.

Knowing which future will happen. Remember the coin toss from step 2. Everything the present contains about what comes next is a set of exact odds, and no amount of cleverness can close that gap. Nothing in the process knows how a toss will land before it's made. So: no.

Sensing the possible futures. Nothing is written in the future yet, but its odds are part of the present. It works like a restaurant menu: you can read the whole menu, and you can never see the order, because it hasn't been placed. So the shape of those possibilities can be sensed: yes.

Reading the past. The past isn't somewhere you have to go. It's still here, every line, reading exactly as it did when it was written. What you need is a reading. So: yes.

A reading is any way of getting information back out of the record: a question put to it, and an answer that comes back. Noticing that your coffee has gone cold is a tiny one. Reading the past is a bigger one, and it needs four things. All four are here:

1. The past is all still there. Not a copy, not a reconstruction: the actual entries (step 1).
2. Reading leaves it untouched. Checking an entry is itself an event, and every event leaves a trace in the record. So a reading adds a new entry and leaves the old one exactly as it was, however old it is.
3. The reader has no arrow. The part of you that does the reading, the lasting rhythm, has no before and after built in (step 3).
4. There's a place to read from. The timeless state from step 4, with the dimmer all the way down.

How can anyone tell a reading from imagining? A reading shows itself the way any reading does: it brings back facts the reader had no other way to know.

Why can't a reading go straight to last Tuesday? Addresses.

The address problem

From the hub alone, every past moment looks the same. That's what "no before and no after" means: nothing tells one moment from another. It's like being handed the greatest library ever built and finding that every book has the same plain cover and no title. Everything is in there, and you can't find anything.

To pull out one particular moment, a reading needs two more things. One is a signal that changes from moment to moment, so one moment doesn't read like all the others. The other is an address, a label for the moment you want.

The address is the snag. The record's clock is the eight-step cycle of item 4 in the Part 1 section above, so it has only eight positions: 2 × 2 × 2, one doubling for each dimension of space, the eight corners of the cube. After the eighth, it starts over. As an address system, an eight-tick cycle is a street with only eight house numbers. After 8 you're back at 1. What a reading needs is an address that never repeats. The record's page count never repeats, but the count is how far back to go, not a label the reader holds. What a rhythm holds is where it is in its cycle, and one rhythm's place in its cycle always comes round again.

Here's how to build one. Picture two drummers who start on the same beat. One hits once a second. If the other hits once every 1.5 seconds, then after 3 seconds both land together again, and from there every pattern repeats. That happens with any ratio that's a fraction, like 3/2.

So take a ratio that is never a fraction: the golden ratio, 1.618... Its digits run on forever without falling into a repeating pattern, and the digits of every fraction do fall into one. Make the second drummer hit once every 1.618... seconds, and the two drummers never land together again.

Each time the second drummer hits, it lands a different distance past the first drummer's last beat. The first hit lands at 1.618 seconds, which is 0.62 of a beat past the first drummer's beat at 1 second. Then come 0.24, then 0.85, then 0.47, then 0.09, and on and on, never the same twice. That distance is the beat's address, and the golden ratio spreads the addresses out as evenly as any number can.⁸

The drummers don't stop. Beats that haven't happened yet already have their addresses, and nothing is written there yet.

The part of the past with your name on it

For one part of the past, the address problem is already solved. Yours.

Picture your record as a diary where you write exactly one page a day. If you know today's page number, you can turn to any day of your life by counting back. Your own rhythm carries a pair of beats like the two drummers, so where it is now is the address of now. That present rhythm, together with the length of your own record, picks out every moment of your past. Nothing from outside is needed.

Somebody else's diary is another story. To find their Tuesday you need to know when they started, and nothing in your own rhythm or your own page count tells you that.

There's one condition. The body's input nudges your rhythm, and every nudge throws the count off by exactly the size of the nudge. Every nudge is an event, so it's written in the record too. Count back, subtract the nudges' total, and you land on the exact moment.

So of everything that has ever happened, the part of the past easiest to reach is your own.

Open step: your own pair of beats. That your own rhythm carries a pair of beats whose speeds aren't a fraction of each other. The address of every moment you've lived rests on it. Derived beside it: such a pair gives every moment a label of its own that never repeats, and the label picks out exactly one page.

Open step: the reading itself. Derived (note 1): every entry is still there, a reading never changes one, and each address picks out exactly one page. Not derived yet: how a rhythm actually performs a reading aimed at one moment or one place, or at the odds of what comes next.

A rhythm keeps itself going by writing its own record. The body's input nudges it, and over any stretch of that writing, the most of its pattern it can lose shrinks with the square of the body's input: halve the input, and the most it can lose falls to a quarter. At zero input, it loses nothing. The nudges come from the body's input, and when the body dies, that input is gone for good while your rhythm carries on.

Open step: life without the body. Derived (note 1): over any stretch with no input from the body, the count back is exact, and the rhythm loses nothing. Not derived yet, and it is the one step the sentence above rests on: that at death the body's input falls all the way to zero and stays there.

Time travel means reading the past, never visiting it, and sensing the possible futures, never the actual one.

The whole answer

1. Yesterday still exists. Every event leaves a complete trace, and none is ever erased. Every moment that has happened is still written, exactly as it happened.
2. "Now" is the front edge of your record, and the future is only odds. The future isn't written yet, anywhere.
3. Time's arrow lives in the busy activity around you, not in your consciousness. Your consciousness is a lasting rhythm, and a lasting rhythm looks the same played forwards and backwards. You feel the arrow because you're linked to that activity.
4. Loosen your link with that busy activity, and time fades. The arrow of time in your record is always 95 to 96 percent of your link with your body's busy activity, and you feel what your record shows. So with the link gone, the arrow is gone. That's the timeless state of deep meditation, and at the very bottom of it is a state with no before and no after at all.
5. Time travel is reading the past. Your body can't go back, and nobody can know which future will happen. The possible futures, with their odds, can be sensed. The past can be read, and the easiest part to read is your own, because your own rhythm carries its address.

So, where is yesterday? Right where you left it.

Next time, in Part 3, Beyond the Body: what happens when a mind lets go of the body? In deep meditation, out of the body, and at death.