[quote=@Alfhedil]
<Snipped quote by duck55223>

Neither would "Negative energy", Antimatter, self-replicating nanomachines, or relativistic kill-vehicles, but that's all already been accepted.
[/quote]

Negative energy is a thing that we know how to use right now. We just have no idea how to get it or even if we [i]can[/i] get it.

Besides, RKV are things that we don't have right now purely because nobody specifically wants to use them.