Causality is Overrated

A while back, I was watching a neat YouTube video about how Faster Than Light travel can break causality. Here it is:

My reaction: So what? Causality breaks. Say you are the dude (or dudette) on the space ship that receives a reply to a message you have not yet sent. Presumably, this would be one of the first things tested if FTL is ever discovered/invented, so you would not be surprised. It’s just another day on an FTL ship.

I mentioned this at According to Hoyt and someone replied, “you just threw out all science.” To which I replied, “uh, no.” Here’s why:

“Science” didn’t break when the Earth stopped being the center of the universe. Nor did it break when Earth went back to being the center of the (observable) universe. Of course, Earth did nothing. It just floats in space being Earthy.

Nor did we all panic and throw away starting guns and stop watches when Einstein discovered that there is no such thing as “simultaneous” and time is dependent upon the velocity of the clock.

Just because FTL breaks causality under some circumstances – and I think accidents will be far more amusing than the attempts to do it on purpose – doesn’t mean causality is not real. Space travel “breaks” gravity – ask the folks who have been in space which direction is down (anyone who says, “towards the enemy’s gate” deserves a beer). GPS satellites have “broken” clocks and the devices that use them back-calculate what “simultaneous” would have been, if it really existed, which it doesn’t.

Just because I receive a reply to a message I have not sent – and may not now send – doesn’t mean that I’ll suddenly start having to piss before I drink a beer any more than people floating around in orbit means that water will start running uphill. The circumstances are different and in order to get to FTL, I’ve done _something_ that screws up natural laws – just like getting to orbit. It’s not that random people start floating around when one person reaches orbit – just that person floats. In the same way, just because causality breaks for me, that doesn’t mean cause and effect suddenly stop working across the rest of the universe.

Most of modern science makes no sense (presumably because the universe is deeply strange thing). We’ve put terms on a lot of things, but we really don’t know what any of it is. “Dark matter” is just a term to describe what _might_ be causing the effects we see. We have no idea what it is or if it even exists. “Measurement collapses the wave function” is meaningless because no one can define “measurement”. See also the discussions about what happens if you cross a black hole’s event horizon.

Pet-peeve digression: If anyone actually believed in the many-worlds interpretation of quantum mechanics, it would be very easy to prove: Quantum Suicide is testable (albeit only to the tester, not the bystanders). The short version, for those of you who don’t want to click through: You are the cat.

The point I’m making: I don’t see the possibility of causality violation as a reason to say FTL is impossible. It might result in some extremely strange things happening, but the fact that we are here to consider it is extremely strange.

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