Reverse Causality & Timelessness

What does the idea of faster-than-light travel tell us about ourselves?

Leo Greenwood
4 min readMay 24, 2024


an image that shows light streaks at the camera to denote high speed
Photo by CHUTTERSNAP on Unsplash

Warp drives, travelling through hyperspace, space-ships travelling at or faster than the speed of light. Sounds awesome, right?

There’s just one issue… I can’t figure how that makes any sense.

Oh sure, it’s just science fiction in Star Trek and Star Wars, but people still talk about it, renowned people like Dr. Michio Kaku, even[1].

Light and causation

The speed of light in a vacuum, as you may know, is defined into ‘constant’ status with the number 299,792,458 m/s. The Latin word for speed — celeritas — gives us c, the symbol for the speed of light in a vacuum.

In Einstein’s theories of relativity, nothing can go faster than this universal speed limit, and so ‘c’ is simultaneously the fastest possible speed of causation.

This means that travelling faster than the speed of light would reverse causation and result in you arriving at your destination before you’d even set off.


Isn’t there only one way to arrive at your destination before you set off?
I stand in the centre of Paris. I say, “I want to go to Paris.I think about making a step in the…



Leo Greenwood

The Universe thinks about itself in interesting ways from here. Philosopher, author, in love with the miracle of existence.