Same input, same output
If a result were drawn at random each time, it would change on every try, and you could not show a friend or come back to it later. So these tests are usually built so that the same input always gives the same output (deterministically).
Hashes and seeds
- Join the name and birthday into one string.
- A hash function turns that string into one big number. The same string always becomes the same number.
- That number is the seed for a pseudo-random generator, which picks items from prepared lists in order.
Same seed, same pseudo-random sequence, so you get the same result even ten years later.
Why one character changes everything
Hash functions are designed so a tiny change in input gives a completely different number. One extra space or a birthday one day off changes the whole result, and similar names do not give similar results.
| Input | Result |
|---|---|
| Same name, same birthday | Always the same |
| Only upper/lower case differs | Depends on the app (same in Parallel Lives) |
| Spaces before or after the name | Depends on the app (ignored in Parallel Lives) |
| One space inside the name | Completely different |
| Birthday one day off | Completely different |
So it isn’t fate
The result never changes because the calculation rule is fixed, not because it is destiny. Change the hash function or the lists and the same name gives something else. People add meaning; the number itself has none.
Seeing it in the app
How is it made?
The About tab in Parallel Lives explains it: your name and birth date are folded into a single number, and that number sets the forks, jobs, places, companions and contentment of all six universes. Everything is calculated on your device.
Why today’s universe changes daily
"Today’s universe" mixes today’s date into your seed to pick one of the six. It stays the same all day and changes when the date does. Moving the what-if axes mixes the axis values in too, opening a different six.
The sample name in the screenshots is a placeholder; you can enter any name or nickname.
FAQ
Will a friend’s phone give the same result?
With the same app version, the same name and birthday open the same universes.
Are my name and birthday sent to a server?
No. Parallel Lives calculates on your device and does not send your name or birthday anywhere.
Parallel Lives: The Other You
No sign-up, fully offline. A free Android app made for fun and reflection.