Time travel grammar

"Dude, are you hungry? I haven't eaten since later this afternoon."

It is often held that time travel is difficult to talk about because of shortfalls in the English language. In his science fiction book The Restaurant At The End Of The Universe, Douglas Adams introduces a fictional author "Dr. Dan Streetmentioner" whose own Time-Traveller's Handbook Of 1001 Tense Formations explains at great and convoluted length how to describe events in your past but another person's future, events averted through time travel, events which you are, while speaking, travelling through time to avoid, and many more. This involves the introduction of many new verb tenses and convoluted verb conjugation rules for these tenses.

In fact, existing grammatical rules are already perfectly well-suited to talking about time travel. All we need to do is obey some conventions.

Part one: fixed history

There are multiple distinct models of time travel which a universe may obey. In the simplest model, time travel is impossible and this entire discussion is moot. For the purposes of this first section, we shall assume the second-simplest model of time travel: that there is a single, perfectly internally consistent, rigid timeline, whose history cannot be altered, even though time travel is, to whatever degree, possible. Fictional universes obeying this model include The Hitchhiker's Guide To The Galaxy, Twelve Monkeys and Bill & Ted's Excellent Adventure.

Lesson 1

The first step to time travel conversations is to abandon an assumption: objectivity.

When time travel doesn't exist, the past, present and future are (barring relativistic effects) absolute and universal. My past is your past is the world's past. But in a universe with time travel, you no longer necessarily share a future or a past with the person or people with whom you are speaking. Only the universe itself has an objective past and future anymore. Events in your past may actually be in the future chronologically, because you travelled back in time to where you are now. You may have experienced the same event from different angles at different times in your personal history.

Time is subjective, which means statements about "the past", "the present" and "the future" are ambiguous.

There's actually a lot of good news in this area, though. Firstly, space is already subjective. While we're facing each other, my left is your right, and if we're on different continents, then what's a mile away for me is ten thousand miles away for you. Conventions already exist to handle problems like this, and these conventions are very readily adapted for analogous situations where, for example, an event in my past is an event in your future, or when an event twenty years in your past is only twenty minutes in my past.

Secondly, the problem of subjective time already exists in the real world even without time travel. It's called the postal service (or more generally, asynchronous communication). Suppose an event is due to occur tomorrow, and you write a letter about it and send it standard class air mail to the other side of the world. By the time the recipient reads the letter, the event will be in the past. What tense should you use, then, when writing? Well, you would start off with "By the time you get this, the event described will be in the past!" and go on to explain the rest using "should" and "will have" and so on. It's not a big deal. Just pay attention and you can handle this.

None of this involves the introduction of exotic new verb tenses. All you need to do is drop cues and provide context to others in order to clarify your statements about events, while continuing to use existing grammar.

Lesson 1A

The second step after abandoning objectivity is to make sure that your conversation partner does the same. To put it another way, the first cue you should drop is to tell the other person that you're a time traveller. Otherwise, the rest of this is pointless.

If you wish to keep the existence of time travel a secret, then abandon these rules, forget everything you know about the future and consult a conventional English grammar handbook. Better still, avoid conversations with non-time-travellers entirely.

The present tense is always good

"The Greenwich Meridian lies at longitude 0 degrees 0 minutes 0 seconds" is always true no matter where in space you are standing, how fast you are travelling or in what direction.

Likewise, in a fixed history, events remain events no matter the perspective from which they are considered. All of history, in fact, can be thought of as a single static event. Thus, a fixed event in history, such as the President of Malawi being hit in the face with a custard pie on 13 August 1990, can always be correctly referred to using the present tense. "In 1990, the Malawian President is pied in the face" is correct no matter where in history you are when you say this - 1991, 1957, 1990 watching the event happen, travelling through time past 1990 in either direction. It also doesn't matter whether you're talking to somebody in person, talking to them in the past from the future, addressing a group of people at different eras, or writing a letter to future recipients unknown.

Objective tenses for objective events

Assuming that you are speaking to somebody at the same location in history as you, and you aren't in the process of travelling past 1990 in a time machine, it is usually permissible to speak about events in the same general terms as you use in time-travel-free reality. In 1989: "The Malawian President will be pied in 1990". In 1991: "The Malawian President was pied in 1990". Also: "The Malawian President will be pied next year/tomorrow/any day now/soon" and "The Malawian President was pied recently/last year/yesterday/just now". Or omit the qualification entirely, as in "The Malawian President will be pied" and "The Malawian President was pied". In all of these cases, your conversation partner will (or should) assume from context that you are describing the relative locations in time of (1) the pieing and (2) the conversation with respect to objective history in general, not necessarily with respect to you or your conversation partner, both of whom may be time travellers with entirely more complicated perspectives on 1990.

The convention is easily breakable to confusing effect. In 2008: "The Malawian President will be pied in 1990". In 1957: "The Malawian President was pied in 1990". Both of these statements may be subjectively true from your perspective, if you are about to travel back in time to witness the pieing/just travelled back in time from witnessing the pieing. But it's very bad practice!

All of the above only holds if the pieing of the Malawian President is an "objective event" with no specific personal significance to you or your conversation partner, at which neither of you were present, and for which neither of you were responsible. Almost all historical events and news stories fall into this category. But when this is not the case, the rules become more complex:

Subjective tenses for subjective events

In 1990, you pie the Malawian President in the face and then travel back to 1983.

You already know it's acceptable to use the present tense, "I pie the Malawian President in 1990", although this is a somewhat odd phrasing in this case.

But you must be careful using phrases like "I will pie a Malawian in 1990" or just "I'm going to custard-pie the President of Malawi". It is clearer to say "I pied that guy", using the past tense.

Why? Because you're talking about yourself now, not the world at large. This event is part of your subjective past and always will be, no matter where in time you travel. When speaking about events directly affecting yourself, it will usually be assumed by your conversation partner that you are speaking from your own subjective perspective, because this is the most normal way to refer to events in your own timeline. "I will assault the Malawian head of state using custard" implies that this is a plan you intend to carry out sometime in your subjective future, which it isn't. A passive voice, "The Malawian President will be pied by me" is clearer on this point, because it more heavily emphasises the object of the statement.

Similar rules apply when referring to other people. In 1990, let's say your mother pies the President instead. Then you travel back to 1983 to meet her. This time, "I watched you pie the President of Malawi" is appropriate, but "You pied the President of Malawi" is not because this event is not her past as of 1983. "You will pie him" is better.

If, in 1990, your mother threw a custard pie in your face, and you go back to 1983 to confront her about it, both sets of rules apply. "You pied me" and "You're going to pie me" are equally true and meaningful. Take care to ensure that it is clear from context - or simply explicit - that this is an event in your past and her future, because the choice of tense is not going to elucidate this.

When using relative terms, there are no hard rules:

  • "I pied him 24 hours ago" will usually be taken to mean 24 subjective hours ago.
  • "I pied him yesterday" will probably be taken to refer to the previous objective day, i.e. presumably a day earlier in 1983.
  • "I pied him one day ago" is ambiguous.
  • "I will pie him 24 hours ago" is nonsense because of the bad tense.
  • "I pied him seven years from now" is nonsense because of the bad tense.
  • "I will pie him seven years from now" would probably be interpreted as seven objective years in the future, but possibly seven subjective years in your future.

Context is everything in interpreting such statements. But note that these problems are not entirely without precedent. Consider the ambiguity of the term "yesterday" when used after flying across the International Date Line. (That's not to say that these problems are solved; even very carefully-written calendar software can trip up when, for example, scheduling a regular event to occur at 1:30am daily, just before Daylight Saving Time begins.)

The solution is to avoid ambiguous terms. Say "my yesterday" or "your next year" or "24 subjective hours ago" for absolute clarity.

Correct use of the first person

First person pronouns should always be used to refer to your current, present self: the darkness behind your eyes. This becomes criticially important when, due to time travel, there are other versions of you wandering around.

In 1990, you tie your shoelaces. You travel back to 1957. You then wait until 1990 and go and find your past self. Through a pair of binoculars, from across the street, you observe your past self tying his or her shoelaces.

Do not refer to that individual as "myself" and do not smugly announce "I am tying my shoelaces" to third parties. Other versions of you must be referred to using the third person perspective, as in "My past self is tying his/her shoelaces". You may also number the various instances of yourself according to where in their personal timeline this event is taking place. In this example, if your name happened to be "Henrietta", then this would be "Henrietta-1 is tying her shoelaces". You, observing Henrietta-1 through the binoculars, are Henrietta-2.

If Henrietta-1 happened to look up and spot you, she could use the same rules: "Henrietta-2 is watching me tie my shoelaces". She would also be permitted to refer to you has her "future self" and she would not be permitted to say "I am watching myself tie my shoelaces".

It's important to understand how ambiguous sentences like these are without this convention! Remember that with time travel, a person can tie his or her past or future self's shoelaces! So, even with just two Henriettas present, the sentence "I am tying my shoelaces" has four distinct interpretations:

  1. "Henrietta-1 is tying Henrietta-1's shoelaces"
  2. "Henrietta-1 is tying Henrietta-2's shoelaces"
  3. "Henrietta-2 is tying Henrietta-1's shoelaces"
  4. "Henrietta-2 is tying Henrietta-2's shoelaces"

and "I am watching myself tie my shoelaces" has eight:

  1. "Henrietta-1 is watching Henrietta-1 tie Henrietta-1's shoelaces"
  2. "Henrietta-1 is watching Henrietta-1 tie Henrietta-2's shoelaces"
  3. "Henrietta-1 is watching Henrietta-2 tie Henrietta-1's shoelaces"
  4. "Henrietta-1 is watching Henrietta-2 tie Henrietta-2's shoelaces"
  5. "Henrietta-2 is watching Henrietta-1 tie Henrietta-1's shoelaces"
  6. "Henrietta-2 is watching Henrietta-1 tie Henrietta-2's shoelaces"
  7. "Henrietta-2 is watching Henrietta-2 tie Henrietta-1's shoelaces"
  8. "Henrietta-2 is watching Henrietta-2 tie Henrietta-2's shoelaces"

Of course, "I tied my shoelaces" is always correct; this event is still in your personal past.

Part 2: inconsistent history

In more complicated time travel models, history becomes malleable and/or divergent. It may be possible to change history by going back in time; it may be possible to create a new timeline by going back in time. The situation may be even more complex. The best example of this is the Back To The Future series.

In situations like this, we have to abandon another assumption: even the universe itself no longer has an objective past or future. Some of the conventions we came to rely on above are no longer useful.

  1. The use of the present tense to refer to events is still acceptable. You may still say "The President of Malawi is pied in the face in 1990", provided that (1) you add a clarification as to the specific timeline or timelines in which this event appears or (2) this is clear from context. Remember, it is possible to modify history to avert this pieing, or delay it until 1991: it need not occur in 1990 in all timelines.

  2. Use greater care when referring to events in the future-- anybody's future. History is malleable. Nothing is guaranteed to happen the same way every time. All you can make are educated guesses. (This is exactly like time-travel-free reality.)

  3. Use greater care when referring to events in the past-- anybody's past. The day that a protester threw a custard pie in Malawi President's face, an event of international significance, may be erased from history so that only you remember it. It no longer matters that you weren't present or responsible: this event is now personal to you, and must be described as being part of your subjective past.

    If history changes radically, you may find that this is true of every event that has ever directly or indirectly affected you - from the outcome of wars and assassinations to your own birth.

Final notes

Remember the Three Things To Be:

  • Be patient.
  • Be clear.
  • Be calm.

Probably the most aggravating thing to do in a time travel conversation is to complain that conversations about time travel are difficult. Firstly, time travel grammar challenges everybody equally; your conversation partner is probably having just as much difficulty understanding you as you are having in expressing yourself unambiguously. As with every conversation involving specialist terminology, "English, please?" is simply insulting, and certainly isn't going to move you both closer to mutual understanding.

Secondly, time travel grammar isn't difficult unless you make it difficult for yourself. Put it like this: No matter how far you travel through time and how frequently you cause history to diverge or interact with your past and future selves, your experiences will always be linear. There will be a series of events leading up to your present situation, and there will be a series of events following it. What you can remember of your past might be confusing; you might not know anything concrete about your future. Oh, and other people's experiences might differ from your own. Shocking, right?

Good luck!

Discussion (21)

2012-03-26 13:27:57 by qntm:

The President of Malawi on 13 August 1990 was Hastings Kamuzu Banda. https://en.wikipedia.org/wiki/Hastings_Banda

2012-03-26 14:47:49 by GAZZA:

It seems to me you have a problem with the "time cannot be changed" discussion - it is, surely, entirely irrelevant. If history cannot be changed, then time is fixed. If history records that you said, "Henrietta, I will pie that guy in the face twenty minutes ago" at 1200 GMT 1/1/2000, then when you go back from 2012 to that point, despite all your good intentions to correct the grammar you will be powerless to do so; in essence, the ability to follow these rules is a very good clue that you are not in a universe with fixed time. (At the very least it will not seem as if you are). Now of course one could reasonably argue - I would so argue - that you don't really have free will in the present either; however, the crucial fact that preserves the illusion is that you can't go back and try something different, so it feels as if you make a free choice. If you CAN go back and try something different, then if you're living in a fixed time universe you will be unable to avoid realising it when, robot like, your actions are predetermined.

2012-03-26 15:42:13 by ochredragonfire:

Upon reading "No matter how far you travel through time and how frequently you cause history to diverge or interact with your past and future selves, your experiences will always be linear. ", my first impulse was to write a story where you personal experiences are NOT linear. For instance, you could split into two time lines, in each of which you have a linear experience. And then merge the two. Or you experience both at the same time. Or you are a groupmind, consisting only of the time travelers currently at that point in history (which would make your past change drastically as they travel through time)

2012-03-26 17:17:05 by JoetheRat:

So now Banda was the President in 1990? Crap. To the Chronosphere! A nice concise explanation. It seems that most of the time writers use "complex" time travel grammar to emphasize how confusing time travel can be. Whether this is to show how confused the characters are, make the reader think it's more complex than it really is, or to get the reader to feel confused when the author does not think the typical reader will comprehend how complex the scenario is may be a matter of interpretation. The whole thing has also made me more aware of tense and pronouns in general. ochredragonfire: _Slaughterhouse Five_ is a nice perspective of a nonlinear experience in a linear lifeline: jumping to and fro through a person's life - but only from a "awareness" perspective, not an acting one. So it seems. So it goes. It's nowhere near as complex as what you're thinking of, but not a bad jumping off point.

2012-03-27 12:58:19 by Snowyowl:

*Continuum* deals with these issues as well; they use an unchangeable timeline and interestingly arrived at exactly the same conclusion as you did. Even using the present tense for historic events, on the basis that in a few seconds 1990 could be *your* present too. The only thing I would add is that, if it's not clear from context or if you're dealing with someone who isn't very experienced with time travel grammar, you can always just spell it all out with "this happened 2 subjective hours ago and 10 objective years ago". It may help to invent four technical terms for the objective past, objective future, subjective past, and subjective future, (and if applicable, previous and subsequent timelines), just so people's eyes don't glaze over when you babble about subjective versus objective.

2012-03-27 13:18:12 by qntm:

I don't see how inventing four brand new technical terms which nobody understands except you makes things clearer than literally using "subjective past", "subjective future", "objective past" and "objective future" which are perfectly straightforward, universally meaningful English.

2012-03-27 19:28:04 by Snowyowl:

Straightforward, yes. Short, no. I was only thinking that seasoned time travellers (i.e. not the readers of the story) would probably want a faster way to get these concepts across.

2012-03-30 03:38:16 by Isaac:

This article was hilarious to me. I pictured two time travellers attempting to converse and one getting frustrated at how unclear the other is, trying to explain the rules of time grammar, and becoming more frustrated as he failed.

2012-03-30 21:00:14 by P:

I like the idea of gaining the upper hand in an argument with my mother about her assaulting me with custard by travelling 7 years into the past and confronting her then (there? then?). That would give me a fighting chance at least.

2012-03-31 14:07:15 by Aegeus:

I agree that "I will pie him 24 hours ago" is a bad choice, but it seems like you need *something* for events in your subjective future and objective past. In a fixed timeline, all you need is "I pied him 24 hours ago," because it doesn't matter when on the subjective timeline it happened, only that they were pied at that particular point in time. However, in a flexible timeline, whether or not it has subjectively happened could be extremely important. Suppose a dastardly villain is planning to go back in time to pie the President of Malawi. "Dick Dastardly will pie him 24 hours ago" implies "We can prevent Dick from going back in time" while "Dick Dastardly pied him 24 hours ago" implies "We screwed up and need to go back 24 hours." I suppose you'd need to be more explicit in such a case - "In 5 minutes, Dick Dastardly will go back 24 hours and pie the President." If that's too wordy, just talk about the part of the traveling that's relevant: "Dick Dastardly changes the timeline in 5 minutes." or "Dick Dastardly pied the president 24 hours ago."

2012-04-01 21:34:31 by Moravio:

After reading this article, I was extremely disappointed to learn that the president of Malawi was not, in fact, pied in the face in 1990. At least, not in this timeline. I was thinking that for a model where one timeline brings another into being, new words might be needed, but this turns out not to be necessary. When it comes to timelines, we may have a situation where the universe starts with one timeline, and this timeline brings another into being. In this scenario, there can only be one instance of backward time travel in each timeine, and the universe only ever has one timeline (the current timeline of the backward time traveller would be destroyed, the new one would come into being when he travelled backward). Possibly the third simplist model? It this case (even if things get more complicated), "timeline A is before timeline B", "timeline A comes before event X" both make sense. Even "event X happens before event Y" makes sence, if X occurs in 1990 and Y occurs in 1200, but Y is strictly in a subsequent timeline to X. Times of events would be described by a pair (x,y), where x refers to date in the current timeline and y refers to the timeline. In models where we can have multiple backjumps to or from the same timeline, new vocabulary for chronologicality of timelines may be necessary.

2012-04-01 23:57:17 by kylakyor:

@ snowyowl m-past w-past w-future m-future but i kind of agree with Sam

2012-04-11 01:30:28 by roykalyk:

@moravio The system you discribe sound like what happened in the ed stories. as such, your rendering of the idea contains a common mistake. The original timeline of the traveler isn't destroyed, they merely vanish. everyone but them goes on with their lives, at least I thinkwe do.

2012-04-11 15:33:39 by Thomas:

reading this entry has been phenomemally succesful in convincing be that the word "pieing" should be spelt "pying". I'm not sure why this is.

2012-04-27 09:19:37 by Randall:

I came here to mention the C°ntinuum RPG, but it seems Snowyowl beat me to it. Anyway, the rules there are really quite simple: always use present tense unless the event specifically relates to you, in which case use whether it's in your own personal past or future. Maybe it doesn't allow for some of the expressiveness of permitting past and future tenses for certain unambiguous events, but it has the virtue of being simple enough to describe in a sentence. Of course, if this article were one sentence long I doubt Sam would have bothered to write it.

2012-04-27 20:30:21 by Nathan:

"Unless YOU were already having been going to do that!"

2013-06-07 04:49:07 by DanielLC:

"No matter how far you travel through time and how frequently you cause history to diverge or interact with your past and future selves, your experiences will always be linear." If you only use time travel, yes. You might at some point combine memories with you from an alternate timeline, or you from the past, or even just a clone of you whose memory diverged at a specific point in time. Your memory is no longer linear.

2013-07-31 18:34:09 by seraphnb:

Thank you for this! My friends and I were trying to figure out how to have a conversation about physics, with the many-worlds landscape and timelessness etc, and this helped us a lot.

2015-08-31 20:03:45 by Sach:

How I wish I could change the date on this post to 2030 ;-) Everyone here has only thought of the English and the western world's culture in tenses and language. My uncle, a Fransican Monk missionary told me of an African language that has many tenses. The language is Bemba, and I would point you to the heading Tenses and Aspects. https://en.wikipedia.org/wiki/Bemba_language He even wrote a comedic song about learning the language. Some of these tense rules may well help the cause. If you go into the future and see yourself pie a President, in a single time line universe you would rightly be able to say I pied a President, as by observance you saw yourself do it in the future and as the time line will not change it is a definite action that will happen and will pass into history so even though you have not done it in your personal past you will have the knowledge that it will happen so it, in effect has happened in your personal liner memories. The following could be used. I will/have pie/pied a President. I have/will pied/pie a President is wrong as from your standpoint in time you have not yet carried out said pieing and the order of the words will show the listener the correct tense in the statement and the fact you know it will/has happen/happened. I have/will pied/pie a President sounds more like you have already pied a President and are planning to pie another or the same one again (good luck with that as extra security will probably be there). If you just say I will pie a President the listener does not know if this is an intent to pie or that you know it will/has happen/happened. To explain the / you take the words in order so there are two or more tenses in the sentence you say. I will/have pie/pied a President I will pie a President I have pied a President

2018-11-11 18:18:35 by Tulliver Scrim:

What if you are speaking with another time traveler about an event in which you are both involved, from a point in time objectively further along than the event but subjectively in the other persons future and your past, e.g. River Song and the Doctor? For example, if you are saying the other person had a lot of fun at a party, couldn't you say to them 'you had will have had fun'? If the event is in history's future as are you, you would say you will have had fun at the party, as this both will happen and has already, so if you both are at a future point from this party, they already had but still will have had fun. Hopefully I made about as much sense as most time travel books.

2023-07-09 09:36:53 by matt:

I was just googling Dan Streetmentioner... and found this link to my favourite author. I can't stop smiling.

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