Indeed.

So many seem to exude the concept that "today we know precisely how the universe works".

Would one insist that Newtonian physics was the Only Way to Think of Things, prior to Einsteinian? While the speed of light may remain a barrier, it may not. Presuming the ability to be reached by a society which likely possesses scientific knowledge beyond ours, is to be a Roman, and presume the sun travels around the Earth, that the 4 aethers exist, and become angered otherwise.

The problem with this train of thought is that it fails to account for the observations so far. We know that the amount of energy required to accelerate an object increases as its speed approaches the speed of light. We have observed this effect. New physics will never contradict this - they may just put it in a new light, or perhaps discover a new dimension. But they will not invalidate the measurements we have so far.

Note that the observations done in Newton's time were never proved wrong - we just discovered that with better measurement precision and in different regimes of speed, they turn out to have additional small terms.

It is perfectly possible that we'll discover additional extremely weak forces and effects, and they may completely contradict our interpretations of the physical theories we've discovered, but they are unlikely to prove that the facts (measurements themselves) we know now are wrong, at least in the regimes we've noticed them.

> Note that the observations done in Newton's time were never proved wrong - we just discovered that with better measurement precision and in different regimes of speed, they turn out to have additional small terms.

This is not quite the right way to look at it. The general theory of relativity isn't just some unmeasurable difference in the margins of the calculations. There are _real_ situations (e.g. near a black hole) where the predicted properties of relativity totally overwhelm the predicted movements under newtonian physics.

It's not insane to think that there equally are not-yet-predicted situations in which FTL speed is possible, under conditions that have never been possible in the natural universe but are possible with human intervention.

If you don't believe that humans are capable of achieving such situations, look simply at our creation of anti-matter despite ~essentially being unable to find~ rarely finding any in the natural universe.

> The general theory of relativity isn't just some unmeasurable difference in the margins of the calculations. There are _real_ situations (e.g. near a black hole) where the predicted properties of relativity totally overwhelm the predicted movements under newtonian physics.

A much better example of the practical consequences is special relativity's adjustments of the laws of motion, which are necessary for example to synchronize GPS. However, my point is that no such observations had been done in Newton's time (they had no satellites in orbit, nor any black holes to study).

> It's not insane to think that there equally are not-yet-predicted situations in which FTL speed is possible, under conditions that have never been possible in the natural universe but are possible with human intervention.

I do think that imagining we could create conditions that have never happened in the natural universe before in such a way that we overcome what seem to be fundamental constants is a bit insane. Remember that our current understanding is essentially that all objects constantly move with speed c in 4D Minkowsky space time, and that acceleration can only switch the direction of this movement, not the actual length of the movement vector. Moving faster than c in any of the space directions would then require negative speed in the time direction.

It's of course not impossible that this theory is wrong. But there is also no reason to believe that it isn't wrong and that c is just a fundamental constant of the universe that is impossible to go past. The fact that the maximum speed we can travel or measure has increased constantly over humanity's evolution is much, much weaker evidence than all of the data that have led to the theory of special relativity and our understanding of the fundamental limits of speed.

In other words, while it is of course impossible to predict how our science will evolve, my money would be firmly on the c limit being fundamental. I would bet that 5000 years from now, there will be no change in this observation (though the exact nature of the equations of motion, gravity, its relation to particle physics and so on will likely all be significantly different).