I thought it’s about time to sit down and write what does it mean to work on a digital time travel tool, along with some definitions and concepts, since there isn’t probably a single idea that consumes as much of my head as time travel. But I believe time is in itself an interesting enough concept that many people like me would have no problem dedicating their life’s work trying to understand it.
Time is not always intuitive; and that’s exactly the reason why most works that use or expand on time as a concept tend to introduce the biggest shifts, whatever the industry. And is probably also the reason behind Christopher Nolan’s genius. It’s no wonder that no other director in history achieved that level of attraction using a concept that seems so simple yet is so complex.
Lately, the idea of using time as a personal computing platform is so hot in tech. In simpler terms: applications that represent user data on a timeline, no matter the data format.
This is so important because we now use different digital formats & artifacts during our daily lives; and as the diversity of these formats increase, the need for a self-organizing platform is on the rise. Photos, events, activities, notes, habits, todos, projects, conversations, files we can’t just organize all these things ourselves, we need advanced tech to organize our lives for us.
Now time happens to be this self-organizing platform we’re looking for, because time can’t be random; by definition, it’s always organized. Now we can just actively create & consume without worrying about structure. The goal is at some point along the way we’ll be able to just put everything on the timeline, and let it do the magic of visualizing everything together, organizing complex structures, and provide richer contexts.
With a proper understanding of time, our digital apps can become more expected and thus more useful. By unrestrictedly combining independent but time-associated data, apps can be more in-line with our nature. Because mainstream digital environments don’t enable this, yet for us, time is so important. We use it as a fundamental organizing principle for our memories of the past and our plans for the future. We just can’t ignore it.
In this post I will go over:
- How do we think of time
- Digital timelines for personal computing
- How to implement The Tesseract
How to think of time
To start off, time for the most part is a made-up concept. It’s a consensual contract we use to be able to organize our lives and make the most out of the here & now. So we have the clock, which is just a useful tool to measure time, but not interact with it, and then we invented different imaginary scales on top of it, like the year, the month, the week, to be able to quantify time, and therefor make it easier for us.
So what do we generally think about when we think about time? What’s the structure? If, for example, we’d want to imagine time as a visual, how would it look like?
Answer is it varies.
Time as a line: A movie with a start & end
The first model, and the most intuitive, is that time is linear. We see time as a linear progression, with the past locked in behind us, the present as a fleeting moment, and the future a vast unknown yet to unfold. It's like watching a movie - the scenes play out one after another. This is kind of how time feels, right?
In this model, the only things we perceive as real are those things happening now. This model puts extreme emphasis on the present as a real thing, but downplays the role of the future (& the past) as equally real, because we just can’t imagine the three of them existing simultaneously.
While this model is intuitive, it probably feels wrong. Because according to Einstein’s theory of relativity, the past, the present, and the future have to be real at the same time.
Time as a block: A group of Hyperplanes
Heavily simplified, relativity says that time and space are not separated, but one connected spacetime. What does this mean? It means that time isn't just one infinite straight line from the past to the future, but rather, a series of interconnected moments (space + time) existing all at once. So there are infinite “nows” that exist in the universe at any given moment. So what you think is your "now" is just your specific experience of the present, but countless other "nows" exist simultaneously.
One “now” in this context can be represented as an infinite plane that slices the block. This slice represents a specific "now" for an observer. This slice is called a Hyperplane. It could be considered as a cross-section of the block, where we freeze time and take a mega snapshot of the whole universe. Each point on this hyperplane corresponds to the same moment in time for every possible location in the universe from the observer's perspective.
In this model, there is no universal past or future, only a bunch of snapshots like these (moments) stacked on top of each other, which subsequently means that all past & all future have already happened. So time is not like a one-line movie, but more like a block.
The block, then, is the entirety of spacetime—past, present, and future—existing simultaneously. It's not just a static collection of moments but a vast, higher-dimensional structure where all points in time and space are fixed. Imagine a book as an analogy; each page represents a moment in time. The book itself, with all its pages together, is the block universe where every moment is as real as every other, whether it's in the past, present, or future.
Spacetime as a Tesseract: The Hyperspace
Einstein's theory goes even further, it describes this block we mentioned above as a complex, interwoven structure, where past, present, and future not only coexist, but they actually might influence each other.
This is interesting, because as we investigate this deeper, we’re delving more into the theoretical aspect of it all. This theoretical construct where past, present, and future might influence each other is, by definition, adding one more dimension (time) to the normal 3-dimensional block (space). The result of this addition is a 4-dimensional construct, called The Tesseract (a hyperspace).
The block model implies the static state of time. But The Tesseract model implies that time can be navigated and potentially manipulated, with different layers of time influencing each other in a high-dimensional construct.
I get this might seem so convoluted to grasp to anyone, including myself, partly because we can’t imagine or visualize more than a 3-dimensional construct. But the visual we saw in Interstellar made this seem quite understandable.
The scene from Interstellar focused on a certain point (location) on the block, which was Murph’s room. And then when Cooper entered The Tesseract, he was actually able to navigate through the different “nows” of this specific location, that is to say, he was traveling through time. Which was only made possible by this 4-dimensional construct, The Tesseract. From there, he was deep in the fabric; he was able to influence the past through connecting her present & her past together.
Now why is any of this interesting?
Two main points. Each is probably extensible to its own essay form.
1/ Predetermination of the timeline
The predetermination of the timeline implies that every event, action, and thought that occurred in our past has led us to our present and will shape our future. This concept challenges the notion of free will because it suggests that our path is already laid out for us in some way. While this offers a sense of continuity and purpose, as every moment of our lives becomes a meaningful part of a larger narrative, it also imposes questions about the role of human consciousness in the fabric of spacetime. If the timeline is predetermined, what role does consciousness play?
2/ Connectedness of time
Normally, we believe the past affects the future. But if time is more like a web than a straight line, could the future ever influence the past? This might sound strange, but in a world where spacetime is like a book, flipping ahead or behind isn't as far-fetched as it seems.
This connectedness aspect of time, opens a whole lot of even more interesting ideas. If time is that connected, it means that nothing from the past is ever insignificant, even the smallest things. So imagine all moments we have lived, all experiences we enjoyed, all people we met, all places we have gone, and even all music we listened to.
The possibility that the past & future are always connected means that nothing is ever random, and nothing happens without a reason even if we don’t see it yet. This single idea of connectedness suddenly means that even the simplest of moments could be precious simply because we don’t know what could possibly happen because of it, right?
The model of experiencing time as a linear structure doesn’t account for any of this. But, if time is non-linear, and is much more complex, then this means that at any point of time, something could happen in our future that is directly influenced by something that did happen in our past, and vice-versa.
In my worldview, this very simple notion just makes life worth it, because the absence of it makes life unbearable! The idea of going through time and doing things without ever having anything to show for it is so painful for me.
It adds meaning to know that every moment in time we have lived is still alive somewhere, and will not vanish till the end of time. Just snappingly makes everything so much more worth it.
“Things change, people change, and most importantly, you change, but that doesn't always mean that older snapshots were false. And that's why I value them so much.”
Digital Timelines
So let’s pick up from where we left about organizing our lives on a digital timeline. The idea is simple: We want to have a holistic view of everything happening in our lives, and we want to gather as much data from our days as possible but we don’t want to interfere much. We want it to just happen.
How to do that? And why a “Digital Timeline”?
Every piece of data on our phone or wearable already has a timestamp by default, so every digital item we create or interact with already has time among other info in a structure called “metadata”. In this regard, a digital timeline is enabling the automatic organization of these items just by utilizing their timestamps, without them even having to be in the same format, just the timestamps will do.
Ultimately, this can enable using time as a personal computing platform, which means you can eventually search anything that happened in your life from within one interface. So think about searching for a place, a memory, an activity, a friend, a project, a meeting, in one search bar.
So Digital Timelines are really just the modern way of visualizing and interacting with time-based data, where all our digital things can be gathered together and used as needed regardless of their type or source. In contrast to today’s default, which only permits the use of some specific data types within some specific apps or environments with pre-determined interfaces.
By stacking different layers of data on top of each other –or even next to each other–, we can create a rich, stacked view of our past activities and experiences.
This can include everything from life events, work tasks, health data, and even our music listening history. The key here is that each layer represents a different aspect of our lives, and by viewing them together, we can gain a more comprehensive understanding of our past and how different elements of our lives intersect and interact.
Now implementing this rich digital timeline can be done in multiple ways.
There aren’t probably many people talking about this. But every now and then I come across someone’s work and it sparks all sorts of questions & directions like fireworks. So fact is there are several concepts exist that are more or less trying to tackle the topic. Creators of these concepts often either pursue them and turn them into functional apps, or stop at discussing the concept in a blog or on a forum maybe. But either way, these concepts at least prove that even a partial digital time travel is possible using what we have.
So in the this section I want to go over some exciting examples that try to visualize a few or more digital data formats on a timeline, and what I do think is the best option in my opinion.
Example I: Calendars
One way could be stacking everything on top of a calendar. This approach uses the calendar view with day columns as the basis for stacking different data formats.
“Something I never really noticed before is that we only use our calendars to look forward in time, never to reflect on things that happened in the past. That feels like a missed opportunity.”
“The idea of visualizing data from other applications in form of calendar events feels incredibly powerful. What if I could see health data alongside my work activities, for example?”
“My biggest gripe with almost all self-tracking tools is that they are input-only devices. They are able to collect data, but unable to return any meaningful output. My Garmin watch can tell my current level of stress based on my heart-rate variability, but not what has caused that stress or how I can prevent it in the future. It lacks context.
Once I view the data alongside other events, however, things start to make more sense. Adding workouts or meditation sessions, for example, would give me even more context to understand (and manage) stress.”
“Sleep is another data layer that would make a lot more sense in my calendar than in a standalone app. I already block time in my calendar for sleep (mostly as a DNS-memo to coworkers in other time zones), so why not add sleep quality data directly to that calendar event?
This way I could plan my day ahead with a lot more accuracy. Fully recharged after a solid eight hours of sleep? Block more focus time. Lack of deep sleep? Add another coffee break to the agenda.”
“This example is particularly interesting because it leverages all of our calendar’s time travel capabilities. It allows us to shape the future by studying the past.”
“Once you start to see the calendar as a time machine that covers more than just future plans, you’ll realize that almost any activity could live in your calendar. As long as it has a time dimension, it can be visualized as a native calendar layer.”
“Most of these data layers are pretty meaningless in isolation; it’s only when we view them alongside each other that they unlock their value. Even a Spotify layer starts to make sense when you look at it in combination with stress data (which music calms me down?), productivity metrics (which music helps me focus?), or personal activities from the past (nostalgia).”
“These changes would turn the calendar into an actual tool for thought, where time serves as the scaffolding for our future plans and our memory palaces of the past.”
Another interesting implementation of the above concept is Amie – It focuses on calendar views, and tries to represent all sorts of digital primitives on top of it.
Example II: Emails, Notes, Tasks
Few weeks ago I was in a zoom call with someone from the community, he pointed me towards this gem of an article:
This is the article that quickly inspired me to write this piece. Because:
1. it’s respectable work in terms of implementing an actual digital life timeline
2. it builds upon the concept we discussed earlier – interacting with different points on the timeline, where the author is connecting items from the past to items from the present and to items from the future (notes, todos, emails, calls, events)
Here’s a demo video of the whole thing:
“I frequently find myself reaching for my digital things on dimensions of time, but mainstream software of the day almost always falls short.”
“Speaking broadly of varying types of digital items (projects, conversations, files, …): some things have a clear start date, and fade out over time; some things develop in importance over time, from near none to one of the most important things in your days; some things matter for just a day, some things matter for the entire year. Sometimes we know in advance how long something will be relevant; other times, we can’t predict this in advance.”
Related: Change of priorities: ref I, ref II
“It gives you this new dimension of context for free, as these things are related to one another, but you didn’t have to set up an association between them. When time is your organizing principle, your things organize themselves.”
“You might remember that last March was when you went on that ski trip, and a receipt you’re looking for comes right after it. Time enables this kind of “orienteering” we do in personal computing, where we navigate directly to something in a known location, and browse from there to the desired result. You’ve likely had this experience when looking for an old picture in your phone’s camera roll: you navigate directly to photos in a known time frame, then look more closely forward or backward from there.”
“One of the challenging aspects of the design was bringing all of these things into one interface. The solution may be obvious in retrospect, but took some iteration to feel right.”
“How to display the primary timeline at different levels of granularity? How might it display summaries of larger timescales, such as the last week, a month, or an entire year? Items which are threaded might be collapsed together, and items which were important for longer periods of time might be made more prominent.”
Rest of the highlights can be viewed in this link.
Example III: Screen Time
As opposed to Apple’s native Screen Time service, some screen time services don’t stop at showing time spent per app, but actually visualize app usage & other screen time activities on a timeline using their start timestamp and end timestamp properties.
This is one of the most detailed timeline apps I’ve used to date. Because it even doesn’t stop here. I can also look into further details deep in the timeline by hovering over a time chunk, which in the screen time activity case, shows me actual paths & links I spent time on! And enables me to take notes on top of them. So I can see the full context – Figma files, Python scripts, meeting notes, browser tabs, all organized by their respective association on the timeline:
Another implementation of a timeline on top of screen time activity is an app called Rewind.
This I consider the first real implementation of “Time as a computing dimension” imho.
It literally allows you to travel back in time, and view your screen in older states, then moreover enables you to search for anything within these older states:
Below is an example I ran on my mac, mentioned in this post from last year:
Example IV: Memories
Late last year, Apple announced “Journal” for iOS 17 to link notes with actual life events.
Though not a full timeline in its literal sense, but it provides a quick way to save moments from your life’s physical timeline by grabbing basic data about moments you live in the background.
Example V: Fitness Trackers
Some fitness trackers like whoop do represent a timeline of activities within the app.
Shown here is one example of how sleep, lifting, and cycling are represented on a day’s timeline, along with heart rate data.
Again, hovering over the timeline provides more context into health data:
So the holy grail of this type of implementation is when we can swipe through a timeline that has our whole life on top of it, not just a single specific item.
Example VI: ✨ Locations ✨
Hyperspaces is a life-tracking app that takes a different premise. It uses location as the basis for all other items, where it creates events from locations I visit.
An event represents a place I was at for an amount of time. This means events can’t overlap, because we can only be at one place at any time. Which also means that we can construct a timeline out of these non-overlapping time chunks. This chunking is not only intuitive, but also allows for all sort of things that can happen on top of these events.
So for example, some life events can look like the following:
- You can be at the gym, listening to music, and doing a workout, all at the same time
- Or you can be at a cafe, attending a work meeting, taking notes, or sending emails
- Or you can be commuting via train, listening to an audiobook, or on a long phone call
- Or you can be walking out in the rain with a friend, or cycling alone on a sunny day
Now the common denominator between all these life events, is that I was at a unique location at any time chunk. Then things may happen within these chunks, which opens the room for building the timeline. Where there are some time chunks that represent the places I was at, and then come all other types of data that is trackable and easy to stick on top of them: Workouts, Music, Calendar Events, Notes, Commutes, Phone Calls, Weather, etc.
Moreover, if there’s something wrong with previous understandings of a timeline, it would be that we should probably not try to fill ALL blocks of time, but rather try fill all interesting events that happened. So for lots of time we spend at home for example, we probably don’t have much detail to add to it. So it’s not that we’d want to add extreme detail into all our time, but only parts of it. This thinking can work as an effective compression technique where we’re trying to compress something that’s so high-res such as time to be more optimized, use less resources, and be realistically searchable.
Once we remove the format restrictions, and accommodate different data from different sources, the potential of the timeline is really limitless. Nothing we cannot actually visualize in parallel, but it becomes a matter of how we’d want to represent and interact with this stuff.
Later on, our memories become tangible digital life events that have coordinates + timestamps.
This very simple idea not only enables the timeline, it also enables 3 additional but equally important interfaces:
1. Life Map
There, we can have a top-view of all places we’ve been at, commuted through, or even ran/cycled at, summarized by day, week, month, or year.
2. Holistic Search Bar
Where we can ask questions about our life events in natural language. These questions can range from memories, to journals, to insights.
For example, I can ask it about health insights, location summaries, patterns of my mental state based on my journals, similar memories from the past to recent events from my life, connections to people I used to be friends with, behaviors I used to adopt, behaviors that changed for the better or worse, etc. The list of possible questions is infinite.
3. Bi-directional Event Linking
It’s crazy that this is something that’s not yet available, but the idea is, up until now there’s just no way to link events that happened in our lives together in any interface. Think about some life event that happened last year, and a similar event that happened this year, and that we’d actually want to link, include, and visualize them together in an easy interface. How do we do it?
This fits nicely with what we discussed above – Connecting events from different points in time. If we’re able to do this -even digitally- we at least have some way of connecting several events & stories from our lives.
The closest thing we have to this is if we have both events logged on calendar (last year’s & this year’s), both of their titles have the same word(s), and then we search calendar by this word, only then we can see them next to each other in calendar search results.
Right there, I just mentioned 3 assumptions in order for this to happen:
- We have to log every life event on calendar
- We have to consistently use the right words for every event
- We have to remember all words we use to name every event
These near-impossible assumptions make it super hard to do the above.
Instead, the premise is that a personal computing assistant should do the same task (linking life events) using one of the 2 ways:
- Coordinates → Similar events are connected together by places
- Semantic Context → Similar events are connected together by notes
The first option explains itself, but I’d like to expand on the second one, because it’s much more interesting, and is one of the core features of Hyperspaces.
Just like we discussed above the possibility of the connection between past, present, and future in real life, and how they influence each other. Now that we have the event data, it’s not far-fetched to enable this exact type of connection via just writing about it, meaning as we live life, and have more events in this tangible format, it gets easier to link learnings from the past to the present, or plans from the present to the future, or insights from either to either!
This makes it much more easier to auto-link life events on an easy interface, with minimal friction, and then from there on, there are really infinite opportunities to build cool features & applications on top of that. Consider how many software applications eventually include the ability to add notes to the things they contain.
Almost all apps discussed above have an “Add a note” feature, where you can write some notes about a workout, a location visited, or a screen time activity item. But if we keep taking notes within sandboxed contexts in half-a-dozen different apps, we don’t really have anything tangible. Not only we do journal in different formats and in different interfaces, but also we don’t have this sleek ability to link those notes, draw connections, revisit them, or even do basic search.
Because a location represent the base at which anything can happen, the interface of the Hyperspaces app allows for taking different notes on the same screen that displays any activities that happen to also exist at the same place and within the same time chunk. From there, the very exact concept of linking time, becomes much easier, because we have bi-directional linking! So via writing, we can actually link or refer to a day or a moment or an activity, which subsequently links the two events together within the same interface, so next time you visit this note, you know that there are probably some certain moments/thoughts/events that led to –or caused by– this exact memory.
Circling back to what we discussed earlier, this further strengthens the idea that nothing happens at random, and that everything happens for a reason. Every single event becomes meaningful on its own, just because we still don’t know what we’ll be linking it to in the future. In that regard, no life experience is ever wasted, no matter how small. And memories never die, nor that they should.
In my world, nothing is ever final, and nothing is ever disconnected. I like to draw connections between things that happen in my life because that’s just my way of adding meaning to it. Sometimes these connections present themselves, other times I have to work hard for it.
For example, connections between ideas, places, or music. I like it when I accidentally come across remixes to a track that I know quite well, or visit two places at different coordinates that end up having the same vibe, or read about the same idea somewhere online in two different contexts, or talk to two different people that spike the same insight in a conversation, or write about the same thought in two different stories at different times, potentially even years apart.
These types of connections I feel strengthen our existing models of how everything around us operates, and repeatedly prove that there is probably so much more about the universe than we might possibly know in a lifetime. Concepts and stories are not sandboxed, they’re meant to be connected; the more we realize these connections, the more we’re able to reason them.
Apps like Hyperspaces help me make sense of these connections, and track them tangibly. It helps me find and retain meaning of all moments I live. In that sense, bi-directional linking is just a normal function of my biological brain, but the app makes it 100 times more manageable.
So I think the underlying concept is clear now: We want to connect as much stuff as possible from different points in time in the easiest way possible. Which subsequently helps keep & tie contexts from different parts & aspects of our lives together on a rich, simple interface.
The digital timeline approach, albeit seeming technologically complex, enables this connectedness we discussed earlier to a certain degree. It makes Time Travel looks like it just turned from a challenge in physics to a challenge in Engineering & Design. Because we now have these digital artifacts we can play with, we just need to figure how to associate them with time, and interact with them (create, edit, revisit) in an easy way.
Much easier to lose meaning than to find it
Today I am 28. Back in the day, everything used to have meaning for me. As a youngster, life was easier, so finding meaning was so easy. Until suddenly, and with enough knowledge & wisdom, I learned it’s much easier to lose meaning than to find it.
I kept trying to search for why that happens, and then I found out maybe it’s because we forget who we are along the way. We don’t visit our memories, so we can’t see any progress. How does it make sense that we take all these photos only to not visit them again? Why do we take photos at a much higher rate than we are able to revisit them? Don’t we take them only to revisit them? Quite paradoxical.
Answer is modern life is fast, so fast. A lot is happening, and faster than we can ever keep context. So we lose memories, places, photos, & moments without even thinking we did it. It’s tragic. We lose so much of ourselves to the fast pace, including our memories, and our stories.
And fact is these two feelings are closely related: Losing memories & losing meaning. If we don’t keep memories fresh in a vault, then they’re probably meaningless to start with. That in itself is the quickest way to depression, which journaling is essentially trying to cure.
So the concept of time as a computing platform offers various opportunities for us to preserve, revisit, and derive meaning from our past experiences. It provides a place where we can visualize all events from our lives, but can also quickly expand on them using our phone. Thus make these events from our life as rich & vibrant as possible, and ready for future reference.
[Bonus] Next Steps: How to construct a digital hybrid Tesseract?
Let’s say we want to construct a real-life time travel machine, one that accesses the 4th dimension, like what we saw in Interstellar, where we can navigate events that happened within the same room, but through time, possibly years. How do we do this?
Hypothetically speaking, if we have a device that can engage our senses in any form of an alternate reality, it could be a good starting point, right? We’d just have to figure out how to project the timeline on the device, and we’re set. Sort of.
Now, in our current physical world, this device exists. And it’s called a Virtual Reality Headset. Why? Because a VR can actually enable an alternate reality, even if it was just briefly.
So here are the steps towards a hybrid time travel reality, and where do we, as humanity, stand about each of them:
- Capture spacetime data: Timestamps & Coordinates (done)
- Add context: Life activity (done)
- More context: Videos in 2D (can be done)
- Even more context: 24/7 360° videos of our worldview in 2D (far fetched)
- Extreme context: Render 24/7 360° videos of our worldview in 3D (currently impossible)
- The Hyperplane: Link timestamps with coordinates on a universe inside the VR
- The Tesseract: Navigate through hyperplanes
This is theoretically simple, but practically hard, at least for now. Because we still don’t have a device that can record a footage of what’s happening in our lives 24/7 (OR DO WE?, hmm). But that said, it seems that current technology is on the verge of being capable of doing that, because what’s an entire life worth of footage in megabytes? Compared to modern day hardware, probably nothing, so I’m confident this will happen in our lifetime.
Thanks for reading!
