The Principles of Time

You can’t figure out how timelines work without some rules to guide you.

Last Updated 10August 2024.

After analysing the first few Loki episodes, I found a need to take some time to revise my theories on how time travel would work. After working on them for some time, I came up with a substantially different basis for how I think time travel would affect the timeline.

I’ve given these rules a lot of thought. The problem with time travel in fiction is that the story will frequently make up the rules as it goes along. After all, time travel is (probably) impossible in real life, so why not? My main problem is that the rules that would be consistent with one series would not make any sense with another. So I’ve decided to create what I call the Principles of Time to govern how I judge how the timeline would be affected. They are based on what I consider to be the most logical, rational outcome of what would happen if time travel were possible.

The Principles

• The Continuum Principle
• The Prime Principle
• The Interference Branch Principle
• The Genetic Branch Principle
• The Outside Continuum Principle
• The Time Loop Principle
• The Speed of Time Principle
• The Shielding Principle

The Continuum Principle

At the point of the big bang, multiple continuums were formed. Each continuum has its own prime timeline and its own branches.

Consequently, any temporal events that occur in one continuum cannot affect any other continuums.

The Prime Principle

The very first timeline of the universe is completely absent from any time travel (up to the moment the first temporal event occurs).

Time travel can still happen and maintain this timeline, as long as actions are not taken that force the timeline to branch.

The Prime Principle allows for the existence of free will in what would otherwise be a deterministic universe. During the Prime Timeline, there is no influence from branched timelines for history to follow a certain path, and thus free will and choice will determine the initial history.

The Interference Branch Principle

This principle is a merging of two other laws and theories:

• Newton’s First Law — that objects in motion remain in motion unless acted on by an external force.
• Novikov’s Self-Consistency Principle — history cannot be altered in a manner that would result in a paradox.

Any potential branching timeline, resulting from the time traveller’s presence, will be influenced by the near-parallel Prime Timeline. Like two physical objects being gravitationally attracted to each other, the potential timeline will be drawn back into the Prime Timeline, resulting in history proceeding in the same series of events — if still possible.

Whether or not the timeline branches depend on the actions of people in the past who is acting on knowledge of the future. If their knowledge of the future leads them to act contrary to how they otherwise would have, then the future will be changed, and the previous timeline will be replaced by the new, branched timeline at some point (see the “Speed of Time Principle” below). If they don’t allow this knowledge to affect their actions, however, history will proceed in a manner consistent with the prior timeline.

In summary, the timeline will branch if the time traveller takes action that interferes with and prevents known history from occurring as recorded.

The Outside Continuum Principle

This principle states that when a traveller is moving through time, during the transit they do not exist within the universe’s current continuum. If they demonstratably still exist in the same continuum, then they are not travelling through time but merely altering the flow of time (e.g., time dilation).

The Time Loop Principle

This principle mainly concerns when time starts looping back on itself over and over again. It has a limited area of effect — the loop might only affect a few ships, or a few individuals, or a small physical area.

When time starts looping, the experienced perspective depends on whether the ship(s) or individual(s) (for simplicity, I’ll be calling them an individual) are inside or outside the loop.

For those inside the loop, they keep experience the same period of time over and over again. The details can be varied as to what, exactly, gets sent back to the start of the loop — sometimes it might be the exact matter, in which case they would experience aging, and sometimes it can be just their memories, in which case they remain unaging. Even death is often not an escape from these loops, as their neural states are looped back onto a living brain.

It can vary as to whether a person is aware of when they’re in a loop — they may be caught inside the loop, but their neural states may not be differentiated enough from their current state to be discernible.

Everything that happens inside the loop occurs outside the universe’s active timeline, instead forming its own local timeline that only merges back with the rest of the universe once the loop is broken.

For those outside the loop, there is only experienced a single timeline.

As to what becomes part of the loop depends entirely on observation and interaction. If anything inside the loop interacts with anything outside the loop (a person seeks out and talks to another person, or makes a phone call, for example), that outside person is now caught inside the loop.

The Speed of Time Principle

I had to give this one a lot of thought, as it can be presented very inconsistently between differences pieces of media.

At this time, I’m going to say that the timeline branches when the quantum probability of the current timeline reaches zero. This means that the timeline will change when it’s forced to change.

Unless otherwise indicated, however, I will assume that timelines change instantaneously for everything downtime from the branching point.

The Shielding Principle

Anything that interacts with time, whether that be a radio that can transmit into the past, or a portal, or an engine, releases a temporal radiation. That radiation temporarily shields exposed individuals from branches to the timeline.

Added 04 August 2024

The Temporal Possession Principle

This principle applies if a person’s method of time travel involves the possession of either their body at a different point in time, or the possession of another person’s body.

From the traveller’s perspective, events occur quite normally. They are in full control of the body they inhabit.

The host remains unconscious if possessed by a time traveller, and upon the traveller departing regains consciousness and control with no memories of the time spent possessed.

Added 10 August 2024

The Genetic Branch Principle

If a temporal event, whether that be information or a physical object from the future arriving in the past, leads to somebody either dying when they historically didn’t die at that time, or existing when they otherwise didn’t exist, then the timeline automatically branches.

This is because the addition or removal of a person from the timeline leads to unpredictable events that alter the course of history. Perhaps somebody’s great-granddaughter was going to make a monumental discovery, but now cannot because the ancestor was killed. Perhaps two people fall in love when they didn’t in prior timelines, and this leads to somebody being born, who later has a child, who later has a child, who ends up inventing something that somebody else was supposed to invent.