5 ms·

It's turtles all the way down -- we don't know what "truth" is, or how one can come to "know" truth (as opposed to just believe it). I'm less informed on these

by kmod 4y ago

It's turtles all the way down -- we don't know what "truth" is, or how one can come to "know" truth (as opposed to just believe it). I'm less informed on these topics so I avoided them, but I've heard that our notion of truth is intimately tied to our experience of physical reality, and it seems easy to imagine aliens that have different experiences of reality. For example, what if aliens are so large that the non-euclidian nature of space becomes obvious to them? Perhaps they would never come up with euclidian geometry. Maybe they would never create the notion of pi. Yes it shows up in other areas but you can certainly imagine an alien civilization that has a different circumference-to-radius ratio or disavows the entire idea of having a constant circumference-to-radius ratio.

lupire 4y ago
> imagine an alien civilization that has a different circumference-to-radius ratio Aliens still live in our Universe with our physics. Are these aliens bigger than the solar system? Maybe a different universe with different parameters could look m athematically different in major ways.
- kmod 4y ago
  Again, talking a bit outside my comfort zone, but I believe our universe's physics say that circles only have a fixed circumference-to-radius ratio at "small" (astronomically) scales. At large enough scales space is curved and the ratio begins to change. In a similar way, a set of different physics would apply to small enough aliens that are principally governed by quantum mechanics. They might never come up with the real numbers because they do not believe that quantities are dense. We could think of more examples -- aliens who typically move at speeds close to the speed of light would have very different conceptions of time, etc.
  - simonh 4y ago
    Our best estimate for the topology of the universe at the largest scale is that it is 'flat'. If it has curvature, it's below the margin of error we are able to measure it at. The only thing we know that can curve space significantly is gravity, but it would take truly stupendously strong gravity fields to significantly change basic results from classical geometry, such as those close to the event horizon of a black hole. Even then we can calculate it accurately nowadays so our results would still correspond to theirs even in those circumstances.
  - msla 4y ago
    If we aren't talking about the same things, we wouldn't be talking about the same things. Part of establishing communication is ensuring we're talking about the same things. Therefore, once we've established communication, we'd be talking about the same things, such as what a flat plane is. If you think humans are the only species capable of comprehending Euclidean geometry, say so, and defend the assertion.
simonh 4y ago
We only need to evaluate what is practically useful. At the end of the day that's all science does - it's a methodology for generating guidelines for what actually works in the real world and for which accuracy, or truth, can be verified. We call those guidelines scientific 'laws', but truth in the absolute sense is less critical than is often made out by both proponents and critics of science. Newton's laws of motion strictly speaking are not true, Einstein proved this, but they are incredibly useful as is the mathematics we use to formalise them. We know that the quantum mechanics and relativity theories we have now and not complete, but that's beside the point. PG is simply pointing out that since aliens, if they exist, live in the same real world we do they will discover a lot of the same practical results we do, and then goes further to suggest they might agree with us about a lot of the less strictly provable ones as well. Going "Oh well but this obscure question here would still be in contention" is, well, somewhat sailing past the point by a little smidgenette. It's criticising a claim I don't think it's reasonable to think PG is making.
- kmod 4y ago
  Agree to disagree, I suppose. Another comment in this thread suggested using the value of pi to demonstrate intelligence, but you can imagine alien civilizations without the same reverence of pi as we do (if they are large enough). I mentioned in another comment that you can also imagine small enough aliens not inventing a real number line because they do not have the experience that everything is infinitely divisible. I believe our difference is that you are presupposing that aliens will have essentially the same experience with reality that we do. I agree that if somehow a separate human civilization evolved in another galaxy, their math would likely look similar to ours. But you can imagine aliens that have very different experiences of "what actually works in the real world" (due to experiencing a different set of physics, such as at a different physical scale) and thus come up with different math.
  - simonh 4y ago
    We already have very robust descriptions of how the world works at every scale, from the planck length all the way up to the limits of the observable universe, and in extremes of environment from the surface of neutron stars, to the roiling virtual particles of empty space. We can calculate behaviours in these environments very precisely right now. Sure, there are things about these environments we still need to learn, but they're not utterly intractable or inconceivable to us. There's a character Rimmer in a comedy series Red Dwarf that's always going on about how aliens would be unimaginable to use because they're alien and everything they do would be... well.. 'alien'. It's poking fun at SF that presents aliens as inherently utterly unintelligible to us simply by virtue of being alien, but frankly that's absurd. Physics doesn't care who or where you are, the same rules apply.
lo_zamoyski 4y ago
> It's turtles all the way down -- we don't know what "truth" is, or how one can come to "know" truth > I've heard that our notion of truth is intimately tied to our experience of physical reality It's been thousands of years since the first retorsion arguments were recorded, and yet I still see obviously self-refuting or self-undermining claims being made and quite often. Like these.

by kmod 4y ago

lupire 4y ago

> imagine an alien civilization that has a different circumference-to-radius ratio Aliens still live in our Universe with our physics. Are these aliens bigger than the solar system? Maybe a different universe with different parameters could look m athematically different in major ways.

kmod 4y ago
Again, talking a bit outside my comfort zone, but I believe our universe's physics say that circles only have a fixed circumference-to-radius ratio at "small" (astronomically) scales. At large enough scales space is curved and the ratio begins to change. In a similar way, a set of different physics would apply to small enough aliens that are principally governed by quantum mechanics. They might never come up with the real numbers because they do not believe that quantities are dense. We could think of more examples -- aliens who typically move at speeds close to the speed of light would have very different conceptions of time, etc.
- simonh 4y ago
  Our best estimate for the topology of the universe at the largest scale is that it is 'flat'. If it has curvature, it's below the margin of error we are able to measure it at. The only thing we know that can curve space significantly is gravity, but it would take truly stupendously strong gravity fields to significantly change basic results from classical geometry, such as those close to the event horizon of a black hole. Even then we can calculate it accurately nowadays so our results would still correspond to theirs even in those circumstances.
- msla 4y ago
  If we aren't talking about the same things, we wouldn't be talking about the same things. Part of establishing communication is ensuring we're talking about the same things. Therefore, once we've established communication, we'd be talking about the same things, such as what a flat plane is. If you think humans are the only species capable of comprehending Euclidean geometry, say so, and defend the assertion.

simonh 4y ago

We only need to evaluate what is practically useful. At the end of the day that's all science does - it's a methodology for generating guidelines for what actually works in the real world and for which accuracy, or truth, can be verified. We call those guidelines scientific 'laws', but truth in the absolute sense is less critical than is often made out by both proponents and critics of science. Newton's laws of motion strictly speaking are not true, Einstein proved this, but they are incredibly useful as is the mathematics we use to formalise them. We know that the quantum mechanics and relativity theories we have now and not complete, but that's beside the point. PG is simply pointing out that since aliens, if they exist, live in the same real world we do they will discover a lot of the same practical results we do, and then goes further to suggest they might agree with us about a lot of the less strictly provable ones as well. Going "Oh well but this obscure question here would still be in contention" is, well, somewhat sailing past the point by a little smidgenette. It's criticising a claim I don't think it's reasonable to think PG is making.

kmod 4y ago
Agree to disagree, I suppose. Another comment in this thread suggested using the value of pi to demonstrate intelligence, but you can imagine alien civilizations without the same reverence of pi as we do (if they are large enough). I mentioned in another comment that you can also imagine small enough aliens not inventing a real number line because they do not have the experience that everything is infinitely divisible. I believe our difference is that you are presupposing that aliens will have essentially the same experience with reality that we do. I agree that if somehow a separate human civilization evolved in another galaxy, their math would likely look similar to ours. But you can imagine aliens that have very different experiences of "what actually works in the real world" (due to experiencing a different set of physics, such as at a different physical scale) and thus come up with different math.
- simonh 4y ago
  We already have very robust descriptions of how the world works at every scale, from the planck length all the way up to the limits of the observable universe, and in extremes of environment from the surface of neutron stars, to the roiling virtual particles of empty space. We can calculate behaviours in these environments very precisely right now. Sure, there are things about these environments we still need to learn, but they're not utterly intractable or inconceivable to us. There's a character Rimmer in a comedy series Red Dwarf that's always going on about how aliens would be unimaginable to use because they're alien and everything they do would be... well.. 'alien'. It's poking fun at SF that presents aliens as inherently utterly unintelligible to us simply by virtue of being alien, but frankly that's absurd. Physics doesn't care who or where you are, the same rules apply.

lo_zamoyski 4y ago

> It's turtles all the way down -- we don't know what "truth" is, or how one can come to "know" truth > I've heard that our notion of truth is intimately tied to our experience of physical reality It's been thousands of years since the first retorsion arguments were recorded, and yet I still see obviously self-refuting or self-undermining claims being made and quite often. Like these.