How about the Alcubierre drive (https://en.wikipedia.org/wiki/Alcubierre_drive)? Yes, there are many unknowns and in filling in those gaps, we might discover warp is impossible after all. But we could also discover the opposite. The reality is that there are potential work arounds that fit our current understanding of physics -- potentially -- and our current understanding of physics is incomplete. In filling in the gaps we might discover more workarounds. Or we might discover that our existing workarounds were duds.
The truth is we won't know until we try. And trying requires the firm belief that we could succeed.
It doesn't do us any good to be pessimistic and announce that we know the physical laws and the physical laws make this impossible. Instead, we should be hopeful and say "Well, here are a dozen things that may or may not work. Let's take a moonshot and see if we can make one of them fly."
The Alcubierre drive can be summed up as "If I have one thing that's impossible (negative matter), I can do something else that's impossible (FTL)." (And, no, negative matter is not antimatter.) It's an intellectual exercise, nothing more.
It's all very well and good to say "don't be pessimistic" but there has to be an open mathematically and physically valid path that makes it possible or all you're doing is wishful thinking. And right now, there isn't even a hint of a practical path that we can follow, either theoretically or experimentally, that enables the possibility of FTL.
Not sure, I haven't done all that much physics since undergrad (it was my major). But with regard to the negative matter issue mentioned by another commenter, there is this in the wikipedia article:
> However, at the close of his original paper[2] Alcubierre argued (following an argument developed by physicists analyzing traversable wormholes[3][4]) that the Casimir vacuum between parallel plates could fulfill the negative-energy requirement for the Alcubierre drive.
The truth is we won't know until we try. And trying requires the firm belief that we could succeed.
It doesn't do us any good to be pessimistic and announce that we know the physical laws and the physical laws make this impossible. Instead, we should be hopeful and say "Well, here are a dozen things that may or may not work. Let's take a moonshot and see if we can make one of them fly."