They're made out of meat (1991) | Hacker News Reader

They're made out of meat (1991)

mit.edu

384 points6502nerdface151 comments

I love how they've said "constrained to C space".

Many people say speed of light is the absolute speed limit of anything or information can travel. Sure it is, which is easily proven by physics. But the physics we know of applies to what we know. There might be something completely different to what we're seeing/observing/theoritising with our smartest people and best equipment.

I'm not saying we can just go faster than C by advancing technology: I know it's limited by relativity and is not a matter of advancing tech.

What I'm saying is that there will probably be advancements in physics and technology so that C limit will of course stay the same, but it will be the physics inside the box whereas a complete new understanding of reality outside the box would be discovered, where things can travel "faster" than C using other dimensions or something that we even haven't thought of yet "outside the box", while still being perfectly compatible with the "regular" "inside the box" physics we love and use today, without violating and relativity rules of our classical physics.

Then they'll probably look back and just laugh at the people who thought C was the absolute limit to everything.

hey, but we'd have to escape the meat first

I've always thought something like this!

When people talk about Aliens, and how long it would take them to get here, I think they miss the point!

Travelling around the Universe would take forever even at the speed of light.

So for Aliens to visit us they most probably have a way to travel unconstrained by what we know as 3D space and time.

I am not physicist, I have no idea LOL

>Travelling around the Universe would take forever even at the speed of light.

It’s even worse than that. Since universe is expanding, there is limited area that is possible to reach with the speed of light. In 200 billion years other galaxies are not going to be visible anymore.

Yup. There was a famous talk with a astrophysicst (forgot who and the name of the talk) where he was demonstrating this in an ELI5 manner which made perfect sense.

He was saying in the future even with the greatest advancements of technology and telescopes if they look at the sky they won't ever see anything and there will be no clue of there were other galaxies (or clusters, not sure) ever, because of expansion and redshift.

It’s depressing. All this stuff that we will never ever be able to explore, and won’t even know exists at some point. I’m not even remotely religious, but sometimes I like to think that after death, we still continue to exist, but free from the constraints of physics, so we can explore the whole universe, through all of space and time.

To be fair about what has been in progress, we have the theoretical possibility of traveling through wormholes, which would allow "traveling" faster than light (well not really going faster than C but simply distorting spacetime itself to reach a point that would require traveling faster than C if we were to travel without distortion) yet there are many practical problems around it.

Of course this doesn't mean that some advanced civilization haven't figured out how to practically use it, which I'm sure we'll also discover (in distant future) if we aren't killed by something else (most likely ourselves).

Unless those aliens are close. There are a few stars within 5 light years, it seems reasonable that a sufficiently advanced civilization could reach us from that close in a reasonable amount of time. if they are really long lived 100 light years seems like the outside edge of reasonable travel distance.

Why do you think 100 light years is the edge of "reasonable travel distance"? I put to you that you are imposing your human standards on other species, assuming that what seems to you to be a long time would also be a long time to another species.

Maybe the aliens have an average livespan of 200k Earth-years. Maybe much more. Maybe they experience time differently, and for them a 100 year journey feels to them like a walk around the block.

100 light years is arbitrary, but even for long lives things it seems like too far - few things on earth are that long lived, and bodies do break down over time, as do spaceships.

Until we know the entire universe (because of the way the universe is expanding this is impossible) we cannot do more than apply our best guess, but I think I hit a good upper limit. Even if I'm off I seems unlikely it is by much.

> Travelling around the Universe would take forever even at the speed of light.

If we're talking about traveling within our galaxy; the distances and thus sub-light travel times involved are huge, however the time spans available are even huger.

On the timescale of planets, a million years is not "forever" but actually a quite trivial amount of time - if there was an almost perfect clone of Earth on the other side of Milky Way where the evolution of multicellular life happened 1% faster than it did here, then they would be tens of millions of years ahead of us, and that is not only enough to reach us at speeds much lower than c but also enough to colonize the whole galaxy while doing so, spending multiple millenia at each planet before moving on.

It’s a pipe dream, we’ve never done anything that isn’t pretty much observed in nature.

Electricity is observable in lightning bolts, nuclear fission is in the stars, birds fly without all the extra fuss. There’s not a single hint that we’ll ever do anything extraordinary.

There are hints that some things exist in more than four dimensions, but that's it. There is no hint that we could apply it to any technology.

Definitely not now or anywhere in near future. But just imagine that there might be something out that even the smartests of the smartests couldn't have imagined until now.

While I don't remotely know what it would be like, I definitely know that there's so much we don't know and have not discovered yet.

Having not even found out secrets about our own planet's oceans, Fermi Paradox, or origin of consciousness/life/death, I'd say there's still much to be discovered in physics.

For what it's worth, I agree with you that something may be discovered some day.

But we currently have absolutely no evidence nor hints that might happen. We actually have more indication that an almighty creator exists than we have indication that humans may someday achieve FTL travel. At least the former has eye-witness testimony spanning hundreds of documented cases across centuries and cultures. FTL travel? Just speculation and Gene Roddenberry.

> more indication that an almighty creator exists

Has that ever not been the case? God has been the goto explanation of anything modern humans didn't understand.

The most brilliant minds at various points couldn't have thought "aye, if we cut a tiny thing inside a metal heavier than lead or glue these tiny things inside air it can create more energy than lighting/gunpowder/dynamite".

Or that wireless communication is possible and sending a manmade moon out around the Earth is also possible, and you can do both for instantly sending light signals, nay, whole books around the globe.

Or virtual worlds that are not bound by any physics (maybe we're dumped into one at birth which can make any observations rather pointless heh).

I can't imagine FTL (although far out theories exist), but our current method of choice is chemical explosions, so there's some massive improvements to be made there.

It is true that evidence for the Almighty is falling, one stick at a time, with many clinging to what remains, but the endpoint is clear. Of all of it, the sense that there is more to the universe than we will ever perceive would be a true loss, if it goes too.

>Definitely not now or anywhere in near future. But just imagine that there might be something out that even the smartests of the smartests couldn't have imagined until now.

Yes, sure, that's always possible but it's not reasonable to take that and then say "therefore maybe X". Maybe fairies. It's not a way to get to any particular conclusion.

But still, FTL travel is not possible in the Universe *with our current understanding of the Universe and its physics*. Maybe it will stay forever like that, or maybe not.

Yes of course, maybe, but we can't say that this is particularly probable and that disbelieving it is laughable, as OP claimed.

Leaving the pull of earth’s gravity is not observed in nature (except for hydrogen/helium and maybe rocks from a huge volcanic event).

Technically correct is best kind of correct.

It’s observed when asteroid or comet that is flying by does gravitationally assisted change of trajectory.

You know, I've never observed one of those. Have you?

He is technically correct though and that is indeed the best kind of correct.

I get the birds and electricity reference, but nuclear fission? Imagine a mediaeval scholar looking at the stars and thinking "I wonder if we could build a nuclear reactor this way?".

Sometimes we simply don't know that we don't know something. It is not enough that something can be observed in the nature, we also need to be able to see it. Currently, we don't see any evidence that faster-than-light travel (or bending space, if you wish) is possible, but we might just not be seeing it.

You should look into the context of other things that was pretty much discovered by luck. Becquerel found something weird with Uranium and Curie found few other materials with radioactive properties without having any sort of theories or prediction at that time.

The question is that if radioactive elements were not naturally present in Earth, would we have known they exist?

That's true, and you can make an argument that we could theoretically find a new kind of substance which then sidesteps all physical limitations known to man. But that's in my opinion as convincing as saying we'll discover magic and go explore the metaverse with it.

> I get the birds and electricity reference, but nuclear fission?

That was fusion, but you can look into natural nuclear reactors (I think first discovered in Gabon) for the fission.

https://en.m.wikipedia.org/wiki/Natural_nuclear_fission_reac...

> The conditions under which a natural nuclear reactor could exist had been predicted in 1956 by Paul Kazuo Kuroda.[1] The phenomenon was discovered in 1972 in Oklo, Gabon by French physicist Francis Perrin under conditions very similar to what was predicted.

So not only did we not learn by observing the natural phenomena in this case, we actually predicted it (accurately, it seems).

I think the thesis being debated in this thread is the possibility of learning based on observation. No one was claiming that all discoveries were actually made this way.

It is false. There are parts of mathematics that have no known application to physics.

Comment doesn't say there are, or was it edited?

Yeah but that's in hindsight though. There are many things that were theorized before to exist based on new physics without direct observations already been made, after which a search confirmed there existence (e.g. black holes). That basically expanded our understanding/knowledge of nature.

In nature, we observe the distance between two galaxies increasing faster than light, the intervening space increasing in size without their speed increasing.

Since the distance between two galaxies isn't made of stuff, it's allowed to 'expand faster than light'. There's other examples of the same thing, and we know how to do it. But it can't be used for anything useful.

If you point a light at the moon, and slide your hand in front of the light, the shadow can also "move" faster than light accross the surface of the moon. But the shadow isn't an object that moves to the side, it's really many lightwaves moving forwards (or their absence), so again there's no real thing moving faster than c that could transmit information.

Some materials can be made to have an index of refraction below 1, so that light's phase velocity becomes 'faster than light' (while the group velocity, which is the speed of light, remains the speed of light).

So you can end up with speed values in nature above c, but in all those cases it's not matter or information, so you can't move anything tangible faster than light.

You can see that as an outside-the-box where things move faster than light, and that's fine, but these can never be used to go back inside the box with some real thing that has moved faster than light. That'd break the box, and so any outside-the-box you create can't be usedul inside

I don't know. No other animal figured X-rays. Or neutrinos. There were (are?) things to be discovered only by going as anal as humanely possible at probing reality.

Disclaimer: Non-Educated Delinquent asking...

I presume String Theory has not been observered yet, thus it remains a theory?

You don't observe a theory. You build an experiment which will either confirm or discard (falsify) the theory, and observe its outcome. The theory remains a theory even in the positive outcome, for it can still be further falsified by other experiments.

(and yes it is impossible to build an experiment for string theory so far with energy levels humanity possesses)

No experiment that could test what is called string theory is known of. So, it is still a speculation, not properly a theory. But it is an extraordinarily detailed speculation. Progress is measured by discovering details that imply or contradict current theory, relying on the "correspondence principle".

If tests for it are ever devised, and it survives, it will be a "Grand Unified Theory" that encompasses general relativity and quantum mechanics, the way those do Newtonian mechanics. Theory is the end state, not the beginning.

In between speculation and theory is hypothesis, a treatment of actual evidence that does not fit into, or anyway is not covered by, the currently favored theory, which has come to be called the Standard Model. This has happened in quantum physics many times, and the theory ends up altered to fit, getting a little more complicated each time. It has lately been hard to find anything new that the Standard Model doesn't get right. Lately, people complain that its numbers are arbitrary and not esthetically pleasing.

But the Standard Model has long been known to be incompatible with General Relativity. So far we have not found cracks in either one. Chances are it will be centuries before we could properly test a grand synthesis, if we could invent one. "String theory" might hold the outlines of such a synthesis, or might be just a mathematical oddity with curiously physical qualities, a model of a possible universe that does not happen to match ours. Even our great-grandchildren will most likely never know.

Maybe faster than light travel is clearly observable in dark matter or quantum entanglement

What about:

The wheel

Plastics

Internet

Memes

There’s still consciousness left in the space of things we can easily observe on nature but can’t yet explain.

Going from "we can't explain it" to "might be new Physics" is quite a stretch.

When doing path integrals for predicting particle interactions, we have to consider ALL possible paths and QED matches very, very well its predictions. So any new force has to either require huge amounts of energy or interact very, very rarely.

So in a nutshell, you'll have to explain how this fifth force of nature powering consciousness in our brain fits with this understanding. Given that we know consciousness can be altered or turned off by drugs, and that it is linked to the chemical and biological processes of life, it's very hard to justify the invocation of whole new Physics to explain it.

While obvious, it never occurred to me to argue that we probably don’t need new physics to explain consciousness in this manner. Thanks for that!

Consciousness plausibly plays a substantial role in causality though, something that was being discussed higher in the thread.

There's nothing about consciousness that even suggests that it might break causality - it's as bound by causality as everything else.

>> There’s still consciousness left in the space of things we can easily observe on nature but can’t yet explain.

> When doing path integrals for predicting particle interactions, we have to consider ALL possible paths and QED matches very, very well its predictions. So any new force has to either require huge amounts of energy or interact very, very rarely.

Is consciousness, and the causal role that it plays in reality, fully understood by QED theory? It has high predictive power of future states in a system where consciousness is present?

I see elsewhere you deploy:

> Honestly, it just sounds like human exceptionalism and God of the gaps all over again. I find it pretty hard to justify "we don't know exactly therefore I can invoke magic".

This is a rhetorical technique that can be used in both directions, it would be not difficult to put silly words into your mouth also - the neat thing about reality is that it fully supports describing and perceiving it other than it really is. Typically, people tend to dislike when others do this (if they describe it in a way inconsistent with how they experience it), but enjoy doing it themselves.

> any new force has to either require huge amounts of energy or interact very, very rarely.

That or it completely breaks the rules of physics as we know it. Given that physics has zero explanation for consciousness that hardy seems unlikely.

We can't explain it, but we do have some constraints: consciousness acts on the physical world and is definitely affected very directly by it. At some point it has to interact with the plain old boring Physics governing literally everything about our neurons and our bodies. And yeah, it's hard to explain how our puny brains can interact with this mysterious non-Standard-Model-Physics while particle accelerators, cosmic rays and neutron stars cannot.

Honestly, it just sounds like human exceptionalism and God of the gaps all over again. I find it pretty hard to justify "we don't know exactly therefore I can invoke magic". And not that I'm particularly skilled in philosophy, but AFAIK even Descartes wasn't able to go too far with dualism (which seems to be what you're arguing for).

You either accept scientific method, and then there will be no advancements to go faster than speed of light, or you don’t and then all bets are off and discussion is pointless.

"No genius ever transcends his own epoch or is much aware of advances possible only a half-century in his future." -- Erich Fromm

Perhaps an exception is Da Vinci. Generally though, there's a separate class of those with rich, intuitive imaginations, but without the ability to fill in the details. They have the odd ability to be right more than half the time. Early computer "sci-fi" thinkers, and I'd include visionaries like Ada Lovelace there, have interpreted our internet hundreds of years in advance. At that time there was nothing comparable in nature to take as an analogy.

Past performance is no guarantee of future success. Everything discovered until now has been the low hanging fruit. The pattern is that it's only getting harder to discover new secrets of nature. Today it requires decades of education, rare genius, and a massive amount of work and luck.

There will likely come a point at which reaching new discoveries requires more energy, resources, and time than any human(s) can afford.

I'm not saying we shouldn't try, but accept that diminishing returns will kick in at some point. We live on a finite planet as a precarious existence. Learning to first live sustainably is probably a better bet than burning the earth to send few people to another planet for a while.

> I'm not saying we shouldn't try, but accept that diminishing returns will kick in at some point.

You're most probably right Paul. I agree with Thiel and Graeber (in their now famous conversation) that this began 20 or 30 years ago.

> The pattern is that it's only getting harder to discover new secrets of nature.

Not sure about that. What pattern do you mean? There have been stalls, hiatus and centuries of dark-age. That "past performance is no guarantee of future success" swings both ways. No strong epistemological statements can be made. Maybe the patterns we see have more to do with power dynamics than opportunity.

> Everything discovered until now has been the low hanging fruit.

We cannot know that. Imagine the discovery of a new force that connects electrodynamics and gravity, or an extraordinary development in mathematics that changes the way we see data and statistics. These could seed a 100 year run of paradigm shifts.

> Today it requires decades of education,

I've been on this line of thought too. I did a talk at Kings College on the problem of the "pulled up ladder", the resilience of innovation and the possibility of reconstructing a post-calamity society due to lost knowledge and the apparently insurmountable demands of education. But as I think more on it, hasn't every epoch faced the same challenge. It's terrifying when viewed as an individual prospect, but on a collective scale we always advance.

> There will likely come a point at which reaching new discoveries requires more energy, resources, and time than any human(s) can afford.

This might be a bit Malthusian. Let's hold out hope for genius and luck too.

> We live on a finite planet as a precarious existence. Learning to first live sustainable is probably a better bet than burning the earth to send few people to another planet for a while.

That's an interesting debate. I also have reservations on the expansive/exploratory mind-set. It's a cliche to say it, but very few people understand the scales, energy and likely opporunity from space. A period of sustainable consolidation might be what we need. On the other hand some will wish to push on regardless and I don't think anyone ought to discourage them or that they need to "burn the planet" to do so.

There already several hacks around speed of light in physics:

Space itself expands faster than C. How is this possible? Well it doesn't count if the space itself is expanding

Wormholes have been theorized by Einstein among others and allow FTL travel. How is this possible? Well you dont travel faster than light inside the wormhole only if you count the distance the long way

Tachyons are particles that travel faster than light. How is this possible? Well you can travel faster than light but you cannot accelerate to a speed faster than C (sure..)

>Many people say speed of light is the absolute speed limit of anything or information can travel. Sure it is, which is easily proven by physics.

I remember reading that special relativity does not prevent faster-than-light travel, but does prevent accelerating a mass to the speed of light. That doesn't preclude things existing that have always had a faster-than-light velocity.

How such things could originate would be an interesting question for sci-fi.

Right, relativity doesn't say anything about technology or non-relativistic physical processes. It just provides equations, into which you plug in distributions of matter and energy, from which you can calculate a spacetime geometry.

The problem is, faster than light travel violates causality in some reference frames [1]. This is a big problem. Forget grandpa-killing travellers; even several bits of time travelling information allows one to easily solve NP-complete problems (it's an even more powerful mode of computation, actually) [2]

Any new physics that allows for FTL must be very weird, even in a logical sense.

[1]: https://physics.stackexchange.com/questions/52249/how-does-f... [2]: https://www.scottaaronson.com/democritus/lec19.html

I guess then causality will be broken if some external force introduces FTL/time travel to our handful of dimensions. Looking at our 4D hypercube of space time, any point in that x|y|z|t space becomes mutable, whats the problem? ;) (I know you need at least one new "time" dimension then to have mutability, this is difficult to talk about. And then somebody in 6D will find that very cute..)

Except that 6D mathematics, and even physics, is routine. Mathematicians and physicists solve problems in more dimensions that that without breaking step these days, and in fact have done for generations at this point. A lot of things like that, which non-specialists think are spooky and weird and unknown, are actually old hat.

And? Exactly my point, nothing spooky about it. At first you look at it in 4d, then 5, then 6..

Right, it's boring and routine maths, but there's no evidence that sort of mathematics will somehow bypass the rest of mathematics and physics. It's like suggesting that long division might solve quantum non-locality.

Or it could all match up - aren't several dimensions the very core of e.g. field theory? No idea, really, as you can tell I'm not an expert, just throwing around random words in a thread that is ultimately based on a SF story.

Yes it is, like I said it's very well known and understood. It's not a wild poorly understood frontier full of unimaginable possibilities. The actual maths of n-dimensional geometry is dull as ditchwater. There's no magic lurking there.

A stupid question.

What’s wrong with breaking causality?

Primer

We observe causality in our universe and day-to-day lives. If FTL movement is possible, you might expect at least some particles to be doing it, and that there'd be closed timelike curves or causality breaking happening already in nature, and we don't.

It's not clear what 'breaking causality' would look like. It's like saying what if you made 0 equal 1?

Well that’s relatively easy. Some object (or particle if you like) appears out of nowhere and causes the events to happen that make it go time travel and appear out of nowhere and cause… you get the idea. Something caused the entire universe, before “time” was even a thing (or there is much more to it). Why couldn’t that something cause few events to cause themselves in an already “deployed” spacetime?

We observe causality

If we can’t observe something it may just mean it’s rare and/or hard to detect.

I understand that probability of me asking this first time is zero and people definitely brought that up and analyzed why this is not the case. I’m interested in reasoning and whether it’s just a rule, like conservation of information (is it so?), or if there is something fundamental preventing it completely.

Everything in the universe is connected to, and influences everything else. Suppose I hit the cue ball on a very low friction billiard table really hard and cause a cascade of collisions, such that some of the balls undergo 20 impacts. That's a lot, but not inconceivable.

Even extremely tiny variations in the initial movement of the cue ball or configuration of the balls can cause the final configuration on the table to be completely different. How tiny? Well, even the removal of a single electron from an atom over ten billion lightyears away could cause a measurable change in the position of some of the balls when they come to rest. That's how interconnected everything is, and how small changes are vastly magnified by cascades of events.

Breaking causality is basically time travel. It would in theory allow future events to change the conditions that lead to our present. Timelines are extremely unstable. Even the most minuscule change could make our present utterly impossible or unrecognisable. A stable consistent universe isn't possible in the presence of causality violations.

So it just makes it very unlikely, right? If I think about the universe as a spreadsheet, there is a large number of formulas, but they are never cyclic, and only look “up” and to the sides, through some lorentz addressing so to say. And dependencies in it are massive, every cell looks at everything up-around it.

We could definitely make a spreadsheet that is circular in parts, e.g. make it find low, middle and high solutions to some cyclic equality group that only resolves to e.g. 1, 2 and 3. But then we have to include all other parameters from up-around and it is ~~ unlikely to solve, makes sense. But I’m curious if that’s correct or provable. The universe seems to have no trouble solving things which we struggle with even at the basic level. Maybe there are coincidences in this spreadsheet that lead to possible dependencies on the future, and then they become a true dependency? We just have no idea how to catch these events.

As if we didn’t have weird physics already. You’re basically saying that the problem with magic is that it works weirdly. But isn’t that the whole point of it?

I understand that it would be TROUBLE at the mathematical and logical level, but that is exactly a box here we’d like to jump out of. Also, aren’t you bothered by the unexplainable fact that the universe somehow adheres to some rules and not the other. What has set them in the first place? Are they even “rules”, or we just accept them naturally, because our most primitive interactions were based on them for few ages?

To be clear, it breaks causality in every reference frame. It is the definition of causality and derived from the definition of reference frames. In fact, c is not really the speed of light, it’s the speed of causality. Light itself could theoretically go slightly slower.

> In fact, c is not really the speed of light, it’s the speed of causality

I like this interpretation. I would be happy if you provide pointers to something written from this perspective.

PBS Space Time did a piece on that. https://youtu.be/msVuCEs8Ydo

This could have been an interesting video, but PBS had some nutty production values. Why did they insist on filling half the screen with some guy waving his arms to distract you? I hope the producer moved on to his true calling - gasoline pump videos.

They have toned that down a bit over the years since that video was recorded six years ago. The videos are really informative, and you can always close your eyes and listen if you like.

Here’s another:

https://physics.stackexchange.com/questions/708173/could-the...

Causality is always hard for me to understand. Imagine an MRI, where you take a 3D object and slice it into a sequence of 2D slices. When you view the 2D slices, is it really true that slice N has any causal relationship to slice N+1? No, of course not. However, when we view a 3D slice of the universe, which is a 4D object in space-time, we want the slices to have a causal relationship.

The big difference that makes causality work is that there is only one timelike dimension (but three spacelike ones).

A purely spacelike curve can wrap back around and close on itself like a circle. But a purely timelike curve just can't turn around: it's like a person on a tightrope who's not allowed to slow down. So it's stuck going to later and later times forever (or to earlier and earlier ones, depending on orientation). (Yes, changes in reference frame broaden that 1D tightrope to a whole "future light cone", but that only allows limited changes of "heading": the time coordinate is guaranteed to be increasing no matter what.) And, roughly speaking, it would cost infinite energy to change from a timelike path to a spacelike one.

You can perform the same thought experiment by pretending you can only “see” in 2 dimensions. Using the MRI example, pretend you “see” sequential slices of the MRI. Prior slices still don’t cause later slices even though one of the dimensions (the axis along which the MRI was taken) is special. And notice, your observation that 3D objects can loop back on themselves is still correct. But that doesn’t really impact how you see the 2D slices.

> Then they'll probably look back and just laugh at the people who thought C was the absolute limit to everything.

We don't look back to Australopithecus and laugh at them.

They didn't make bold claims though (at least in a way that we humans can understand).

However, "c will never be able to be passed" is a very bold claim. IMO we can leave room for exploration by saying "c can't be passed with our current model of physics due to relativity, in the context of what we refer to as spacetime", which would still be correct, yet leave the door open for any future discoveries.

We do laughat alchemists and astrologists though. We don't know what Australopithecus thoyght they knew.

That's my point, when we pass those barriers it won't be "us" anymore. It won't be like looking back at essentially a dumber version of ourselves, but like a distinct species.

>What I'm saying is that there will probably be

That doesn't follow. We can always say there's things we don't know, sure, but it's not reasonable to take that as a justification for saying "Therefore maybe X", with the implication that X is somehow likely, or therefore even possible in reality. Maybe fairies. Maybe whatever. It's not a technique that can lead you to any particular conclusion. It certainly can't tell you anything about the probability of something.

It seems awfully parochial to assume the aliens have to be far away.

There could be plenty right nearby, or right here. We don't even know what is on the sea floor, or not even very deep underground. If trees are thinking, we do not know it. Something that lives a thousand times our speed would be invisible.

If they don't interact with E-M fields, we could walk right through them, or they us. Our ground wouldn't hold them up against gravity, but they could have ground of their own, with a surface a thousand miles up, or down.

I'm not assuming anything, and I'm not the one assigning high probabilities to things conjured entirely from the imagination. That looks a lot more like making assumptions to me.

I enjoy science fiction, science fantasy and even outright fantasy too. It's fun to imagine other worlds, or how our world might have been, or might once be. Imagination is an important part of our lives; but reality consists of what is, and it doesn't care about our preferences and dreams.

In reply to ConstantVigil, who's reply got flagged/dead almost instantly.

>The basis of all creation in regards to humanities progress all starts with the beginnings of a hope or dream...

I agree, this is absolutely true, that's why I said it's so important. The fact is though that only a minuscule tiny fraction of the things ever imagined actually turn out to be true. In fact most of the time we have to be smacked repeatedly in the face by reality before we get it through our skulls that the way we imagine things are isn't the case. I'm all for keeping an open mind.

However imagining things we'd like to be true, and then constructing spurious justifications for think they are probable in the absence of any reason or evidence, is not keeping an open mind. It's the exact opposite.

(If you click on the time-posted field of a dead message, there's an option to "vouch" for it, allowing you to reply directly. Please use it sparingly.)

The age old discussion of "if a tree fell in a forest and nobody heard it, did it really fall?"

> did it really fall?

It's did it make a sound, and revolves around the nature of what a "sound" is. The tree certainly fell.

Indeed. Is the "sound" the brain's interpretation of the vibrations and pressure waves perceived by the eardrum and auditory nerves, or is the sound those vibrations and waves in and of themselves, with no further "processing" necessary for it to be called "sound"? Perhaps we need another new word involved to differentiate the one from the other in discussing "sound"?

There's an argument that aliens are more likely near us than far away: if life on our planet got started via panspermia, then closer planets are more likely to have been seeded with our distant ancestors as well.

I love the idea of panspermia, it’s fascinating, but I think the evidence is against it. If life evolved elsewhere we would expect it to have undergone significant evolutionary development before arriving on Earth, but that does not seem to be the case. The earliest life forms on Earth were incredibly primitive in terms of their molecular construction and biochemical pathways.

Ya but we do know the universe exists without any fucking clue how or why. So, it seems fine to let your mind wander a bit.

Of course, that's an important feature of the way we relate to the world, but that doesn't make whatever we imagine likely or probable as claimed.

That's a sensible position. However, the GP's remark first asserts that our understanding of physical reality is incomplete, which is not unreasonable given that we have not yet reconciled classical and quantum physics. Further, quantum weirdness has strongly underlined the inadequacy of our intuitive perception of 'reality'; it entirely confounds it. It is possible that spatial expanse (distance), for example, is a secondary order phenomena and a side-effect of our being sentient at this scale of things. Bell [1] actually remarked that in his view the reason Einstein resisted the Bohr model was that he was "very much attached to space-time".

[1]: https://youtu.be/BFvJOZ51tmc?t=222

And it's also possible that resolving the issues between relativity and quantum mechanics will have no implications relevant to FTL and such. In fact there's no particular reason to expect that it would. So we're back to just flat out speculation.

That's fine by itself, I love speculation, but that doesn't make this or that probable. It's the extending such speculation to making high confidence definitive statements, as though something's been demonstrated or proved likely, that I'm objecting to.

Yes, but it is not unreasonable speculation. Speculation is not without value.

> but that doesn't make this or that probable.

Of course, that's a given.

Cool , we're in agreement, but it wasn't a given in the comment I was originally replying to which made very strong claims about what is probable.

What happens if we work out how to make 'C' bigger?

Then the constraints still hold true, but possibility space expands.

The speed of light is the speed at which events propagate.

Let’s say something happens 8 light-minutes away, for instance the sun explodes.

For the first 8 minutes, we’d live in a world where the sun hasn’t exploded yet. Then the event reaches us, and for the first time, we can get information about this event.

Perhaps a theoretical physicist can weigh in about whether bent space or a high-dimensional shortcut could change this.

I have the same feeling. Objects may be flying past our planet at many times the speed of light and we would be oblivious to them. I suspect the speed of light is the maximum speed an object can reach whilst still being detectable by conventional means. Once you surpass it things cease to be conventional.

"Algebraist" by Ian Banks is about human exploring a civilization that lives orders of magnitude slower than us. For them universe is easy to colonize because they live so slow that interstellar travel is fast.

We have things on Earth that live very slowly or pause metabolism altogether for long periods of time. It's not a big stretch to imagine a civilization that can do this (and started very early in universe age) that colonized a lot of universe despite speed of light constraint.

I’ve always wondered but if we were blind would we be able to ever know anything about “speed of light” or photons?

It’s…fiction. Made up. Not real. No actual science involved, just grammar.

Another of Terry Bisson's short stories, "Bears Discover Fire", is an absolute gem, and free to read online: https://www.lightspeedmagazine.com/fiction/bears-discover-fi...

+1.

Bears Discover Fire is awesome.

I love the mood of the whole thing, but I wonder if I am missing an obvious symbolism or statement or idea somewhere. Maybe it's just the memories of high school English, but I keep wondering stuff like "do the berries mean something?" or "are the bears supposed to be replacing us?" Are the bears there just to add a bit of surrealism or magical realism, or what?

Maybe that's part of the story, heh. Some of the characters wonder if they are missing something.

I sounds to me like a proposed solution to the Fermi Paradox.

Pretty sure the author is hinting that the berries are being cultivated by the bears, but doesn't want to say it.

The bears are filling in the gap left behind as humanity advances towards the future. Living in the medians both literally and figuratively. They're not replacing us, but what we were.

I remember there was an animation series about "Gummi bears" which definitely cultivated "gummi berries" (with magical properties that made the bears act gummi).

I wonder if there's a connection / reference.

Be there with the bears eating berries.

We have all wondered about hidden meanings.

The bears wonder too!

After all, they are just beginning to discover fire.

What is this thing? We know how to make it happen, but we don't understand it.

Nothing is as obvious as we might hope.

Don't let this trouble you. Just bear with it.

Wonderful share, thank you. The voice of this is so pitch-perfectly 20th century American. Full of folksy little observations that are actually enormous in their scope without being remotely alienating, like this one:

"It looked like only a few of the bears knew how to use fire and were carrying the others along. But isn’t that how it is with everything?"

The very best of what we used to call "old-school". Respectful of experienced reality, not imposing anything on it, but incorporating it into life without fuss.

It was the gesture of leaving cut firewood that stays with me. They are neighbors now, and that's how you are with neighbors, even if you have nothing much to say to one another.

This was also made into a short film: http://www.bearsdiscoverfire.com/watchnow

It’s gorgeous, but I found the story much better.

My favorite film adaptation of https://www.youtube.com/watch?v=7tScAyNaRdQ

It’s very different but reminds me of the line “literally made of chicken” from Mitchell and Webb. https://youtu.be/_pDTiFkXgEE

Please link to the one posted by the director, not some slimeball stealing his work: https://www.youtube.com/watch?v=T6JFTmQCFHg

That is better than I could ever have imagined.

It's great.

Author is still living... https://en.wikipedia.org/wiki/Terry_Bisson

Many times on HN; I'm good with that.

https://hn.algolia.com/?q=Terry+Bisson

They're Made Out of Meat (1991) - https://news.ycombinator.com/item?id=24737993 - Oct 2020 (292 comments)

They're Made Out of Meat [video] - https://news.ycombinator.com/item?id=23436550 - June 2020 (4 comments)

They're made out of meat - https://news.ycombinator.com/item?id=8910420 - Jan 2015 (1 comment)

They're Made out of Meat - https://news.ycombinator.com/item?id=8152131 - Aug 2014 (170 comments)

"They're Made out of Meat?" Short first contact sci-fi story - https://news.ycombinator.com/item?id=3549320 - Feb 2012 (62 comments)

They're made out of Meat - https://news.ycombinator.com/item?id=774139 - Aug 2009 (3 comments)

I never liked the story. The premise that a sentient lifeform would be able to traverse the universe, make contact with wildly different lifeforms, but somehow scoff at the idea of "meat lifeforms" is inconceivable, even stretching my suspension of disbelief to its limits. Especially since the explorers in the story have managed to decipher our communications, our culture (mentioning that we sing) and probed our biology.

I find it funny specifically for that reason.

For me, the story highlights the truly astounding and utterly mysterious fact that consciousness emerges from "material meat" (the brain). How is it possible? Granted, their consciousness is also mysterious, but they are blind to that fact, just as we are to some extent.

It's all about the Mind-Body problem.

Edit: Typos.

I took the timing of the posting to be a reference to the controversy about LaMDA.

I think you missed the fact that the story is meant to be humorous.

It is a nice story because they didnt choose the more likely option to kill us.

I guess in real life (and probably many stories) they would rather attack.

You underestimate how far racists are able to go.

I always interpreted that story as the discussion between two public officials that are withholding a sensational curiosity or even the scientific discovery of this galactic cycle from the galactic public.

Just because of their own prejudices even though they are supposed to welcome any kind of sentience into the galactic community.

"Meat" in this story seems to be some kind of slur to me.

Why aren't they using a more generic and neutral term like "organic" instead? I wonder if those two have evolved from organic lifeforms which are for whatever reasons remembered badly in the civilization those two protagonists are from.

I always thought the point of the story was to draw attention to how we as humans are limited in what our view of a life form is? By writing it from this perspective, the story is a mirror to how absurd our concepts are.

Except here we are, writing stories about non-meat lifeforms. The beings in the story are somehow less worldly than we.

Another good short story: https://www.nature.com/articles/519498a

The short film by Stephen O'Regan based on this is pretty good if you haven't seen it: https://youtu.be/T6JFTmQCFHg

This story is cool but it’s premise always bugged me. “meat” as a concept emerges from our own experience. From an alien point of view, “meat” would appear first as some kind of programmable nanotechnology matter, which is far from the trivialness we express when we talk about “meat”

Maybe as opposed to carbon life form ?

What is weird is that they know what meat is, and don't like it. Like they have meat pests they can't get rid of, or depend on in some unpleasant way they would rather not think about.

The story at its essence pokes fun at philosophers who claim that in silico artificial intelligence is impossible because only meat can think.

Since we're talking SciFi, one of the most interesting treatments of space-time is Vinge's "A Fire Upon the Deep", in which there are different zone of the galaxy that have different space-time characteristics. I find this more interesting than the usual "faster-than-light drive" or "wormhole" sorts of SciFi. (Us engineers are clearly stupid; we actually need to make real things work. SciFi writers just write a high level description, assume that its works as designed, and start the next chapter! :-)

The previous 19 discussions:

https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...

This story never made any sense. If you know what meat is, you are also familiar with large animals with some degree of intelligence. Can’t have one without the other.

An excellent book that greatly expands on this "mystery" is The Mysterious Flame, Conscious Minds in a Material World, Colin McGinn.

Radio show: https://youtu.be/GggK9SjJpuQ

why has no one posted the video

https://youtu.be/7tScAyNaRdQ

Two others did before you

And, hilariously, the guy didn't even link to the original but someone's re-upload.

Such a good short read. Thanks for sharing.

Why would incorporeal beings even have a concept of "meat"?

I think the idea is most intelligences are along the lines of evolved computers (they mention silicon based beings), but that doesn't mean life like ours isn't common too. It just barely ever evolves sentience.

Perhaps bacteria would be considered "meat"

There is also no technical error's they are all meat-based.

@tux3 human brains are constipated. Our current interpretation of data like that from Hubble is that space is expanding. But it could equally be that matter is contracting. Space is the absence of matter. You cannot increase space anymore than you can add ‘cold’to a glass of water. By assuming that light is invariant, we would observe decreasing light frequencies as we measure older light.because We and our rulers have ‘shrunk’. This interpretation also eliminates the need for inventing dark matter and dark energy to explain our observations

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