Thanks, that's what I was afraid of. I guess I've been trying to look for a shortcut, but in the end I'll have to dive much deeper and learn much more to really understand this topic.
I've read the tachyonic antitelephone article several times over the years, but the problem is that (as far as I understand it), this thought experiment exactly boils down to "the numbers don't add up without breaking causality", without really explaining why that is in any intuitive way for me.
Please define "causality", as precisely as you can.
Presumably you'll need a "clock" of some kind, so please describe a clock in a way that it is independent of the speed of light and any particular frame of reference (unless you believe there is a preferred frame of reference. If so, which one is / which ones are?)
Remember that the theory and experiment of special relativity state and show that the speed of light is always measured to be a constant, no matter who measures it and how they are moving with respect to anyone else.
I've read the tachyonic antitelephone article several times over the years, but the problem is that (as far as I understand it), this thought experiment exactly boils down to "the numbers don't add up without breaking causality", without really explaining why that is in any intuitive way for me.