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Comment by colordrops | Hacker News Reader

I think the idea is not whether we could speculate in a useful way about an FTL or otherwise seemingly impossible phenomenon that we are not yet aware of. It's more about the probability that phenomena and technologies that are far beyond our current understanding can exist or not. In all likelihood we would have the intelligence and technology of ants relative to a million year old civilization. We shouldn't limit what is possible in this universe to what ants are able to comprehend and achieve. Even without such an argument, we only need to look at what we thought was possible 500 or 1000 years ago, and extrapolate forward that in all likelihood our currently understood limitations of physics will all but be irrelevant in 1000 years.

Agreed that it's a flight of fancy to speculate on these yet unknown capabilities, but that doesn't mean they aren't highly likely to exist.

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I don't see it that way. 100 years ago we had a million questions about physics, and lots of fundamental values were a mystery. Today the fundamental values have all been measured to a high degree, and we have a few questions about physics and lots of them epistemological.

If in 1M years we have a different view about the universe it won't be because we were wrong about physics today. It will be about something underlying or outside physics?

Every kind of matter that we know about makes up less than 5% of the believed matter in the universe. What's the rest? "Dark matter" and "dark energy" which are effectively empty placeholders. We know almost nothing about them, and yet they're the overwhelming majority of what exists.

Maybe they'll turn out to be boring and useless. Maybe they have even more complex interactions than ordinary matter does. About all we can say today is that there's a mystery 20x more massive than all known matter.

'Almost nothing' is not quite right. We know the fraction to 3 or 4 decimal places. 'What it is' may still be a question but we know precisely what it does

Describing the amount there is and that it exerts gravitational pull says almost nothing about it, assuming it's as complex as anything else in the universe.

We also know that, other than via gravity, if it does interact with matter or EM radiation at all it does so spectacularly weakly.

Erm, seriously?

Or do you only mean classical, newton physics?

Because as far as I know, (quantum) physic is far from explained. Shure we do know a LOT more than we did 100 years ago, but I doubt we have fewer questions. I even suspect it can never be fully understood. Some basic principles, yes. But if the universe is infinitely big and small and it seems it is, there is no full understanding nor resolving all questions. I thought that mindset died out allready. Because before quantum mechanics etc. physicist actually did thought they allmost solved all questions. And then: oh. There might be more ...

I thought the whole idea behind quantum physics is that the universe is NOT infinitely small and that the minimum size / amount is a quantum.

Not at all! -> https://physics.stackexchange.com/questions/9720/does-the-pl...

Sometimes I wonder, how confident were our ancestors when they thought fire was an element, or when the Egyptians made mummies and hoped they would come back to life. Did they have the same level of confidence as we do today? That the "fundamental values have all been measured to a high degree"?

If that's the case, then we can be as wrong as they were.

We don't know what we don't know.

That doesn't imply that we don't know what we do know, however.

It doesn't seem likely that everything we've observed, discovered and experimentally verified about the universe since the beginning of recorded history is simply wrong, or that our level of ignorance about the nature of reality remains constant regardless of the data amassed.

We have absolutely no idea whether the universe or its complexity are infinite. With that out there, it leave the possibility that no matter how much knowledge we amass, it's at best infinitesimal in comparison to all that is possible to know, and at worst, our models will be completely contradicted by some new knowledge that puts previous learning in a different context.

The set of all primes is also infinite, but that doesn't mean it's possible to find an even prime number greater than 2... the universe can be infinite but that doesn't imply the laws governing it are also infinitely varied.

My point was not to state the truth but to show the possibility. Unlike prime numbers, the historical pattern is that our model of reality has changed fundamentally several times.

An easy, however unlikely, example of what could change it again is to find out we are in a simulation.

> nature of reality remains constant regardless of the data amassed.

It does not remain constant. But it remains indeterminable. Ie we can say we know something about the universe. But we cannot say we know x % of the universe simply because we have no way of knowing what 100% is...

We do know that we don't know what we don't know though, which should hopefully reduce the urge to make overly confident statements about the limits of reality.

>Agreed that it's a flight of fancy to speculate on these yet unknown capabilities, but that doesn't mean they aren't highly likely to exist.

It's just as likely that there are constraints on what is possible that we are not aware of. Take Newtonian physics for example. It turns out physical systems are significantly more constrained by relativity than Newton would have supposed. Relativity makes less possible, not more.

We might assume that super advanced civilizations can do things based on our understanding of physics, but we might be wrong. A Newtonian physicist might assume an advanced civilization could accelerate rockets to arbitrarily fast speeds and get to the nearest star in less than 4 years, but would have been wrong.

A Newtonian physicist would also have known that it would take an awesome amount of fuel to accelerate to very high speeds. Being unaware of nuclear power they would have concluded that it's utterly impossible to go fast enough to reach even the nearest star in reasonable time frames.

At 1 g of sustained acceleration you do get to nearby stars in a number of years.

The big impact of relativity is that less time passes on the ship.

> Relativity makes less possible, not more

That's not strictly true. Before relativity, time dilation was not know to be possible.

> Agreed that it's a flight of fancy to speculate on these yet unknown capabilities, but that doesn't mean they aren't highly likely to exist.

Right, but since we have no scientific basis for figuring out which capabilities those would be, the reasonable guess is that EM is the best means of communication. It's more likely that we've figured out some basic physical limitations, even if there exists technologies within those limitations far beyond what we've though up so far.

Sure, and as I mentioned in my comment, I agree there isn't much value to speculating what these unknown phenomena or technology are. But, the value to recognizing that there is non-zero probability that they exist prevents us from making overly confident statements such as "the reason we haven't seen radio signals from other civilizations is because we are the only intelligent species in the universe"

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