So who stores the login information? This is fundamentally the question here.

If you store it centrally you only need to ask for username/password combo.

But then someone needs to store it at a central location for everyone to check against.

If it’s not centralized than the user needs to provide it

Email has a hidden trick up its sleeve and that’s the domain name. In order for an email to be valid, the domain name must contain email info on its DNS records. There’s where you can imply knowledge about where the email/message is to go.

But here in lemmy, my email is just Gmail. There’s no way to find the information on where authentication could be located. Which brings me back to the top of centralization vs decentralization.

The reason it doesn’t disprove it is because the assumption “time travel works” is really just saying, if we ignore some basic rules of physics, what happens to what’s left? It’s a nonesense premise to debate what is basically nothing more than science fiction.

Could the rules we know about the universe be wrong? Absolutely! But discovering those new rules is what will answer that question. Till then, we might as well try and say Harry Potter is just quantum mechanics.