It's very fun watching which "faction" might take over the board.

Demo: https://genetic-life.surge.sh/

Source (ported from the original C++ into Rust/WASM): https://github.com/franky47/genetic-life

It eventually settles down to one large and unstable blob and another stable. Neither move so that's it. But before that it did what I had expected to see with objects meeting and merging

This one is really fun for me. It has a lot of actions and good shapes.

This version does everything in webgl shaders and keeps all state for the simulation in textures / uniforms. This allows it to simulate and draw more particles. Unfortunately it may not run on all devices because it uses some less supported webgl extensions.

What is fooling you is the motion. This is sustained because the system has no conservation principles built in. You can make A-B pairs where B is attracted to A, A is repelled by B, and off they go, zoom. Were the meta-rules devised such that conservation of energy or momentum and such were baked in to whatever system you devised, you would see less exciting structures which would more resemble a late-stage pentamino explosion in the Game of Life.

With a sufficiently large processor, I would like to see this in three dimensions and more options for force, such as dropping off as the inverse of r or r-cubed or even r * log(r), or some "repulsive at a distance, attractive at very close quarters" particles. I have a feeling that such a system would grind to a halt even with clever optimizations.

Oh, there's one of those too! I don't see ways to change the falloff though, just the magnitude...

https://hunar4321.github.io/particle-life/particle_life_3d.h...

>> I have a feeling that such a system would grind to a halt even with clever optimizations.

I took this to mean that they thought there was no falloff calculated at all. If there is, I don't see why substituting a different function, e.g. cube vs square, would be significantly more CPU-intensive.

1) Three dimensions, not two. Therefore distance is not the square root of (delta-x * delta-x + delta-y * delta-y) but the cube root of (delta-x * delta-x + delta-y * delta-y + delta-z * delta-z). More operations.

2) Three dimensions, not two. As you start increasing the number of dimensions, the simulation feels more and more empty. One hundred particles on a line a thousand units long is crowded. One hundred particles on a grid of one thousand by one thousand feels like more "room" for that same number of particles. In a volume of a thousand by a thousand by a thousand, one hundred particles feels too few, and one would naturally increase the number of particles. Naively, which is to say without optimizations, the number of force computed grow as N-squared. More operations.

3) Cube falloff goes by r * r * r, rather than r * r. More operations, by fifty percent. And I did suggest some more exotic functions in there which certainly could be more daunting.

No, it is still a square root. The term under the root is correct, but distance in N dimensions (assuming euclidian space) is just sqrt(sum(delta-n ^ 2))

That seems like a valid belief. Getting to a technological stage such that a species would be detectable over the vast distances of space could indeed be quite rare. You have to also consider the temporal aspect: intelligent, technologically advanced species may have evolved several times but gone extinct before we could notice them. Do other technically advanced species exist in the universe? Probably, but it could be that at any given time there might only be about 1 in any given galaxy and the distances between galaxies are great enough that we'd never likely be able to make contact. (and ~1 per galaxy would still mean that there would be a whole lot of intelligent species out there - it's just that it would be extremely difficult to make contact with any of them)

Its not at all clear in general. It might be true. But it also might not. It seems quite reasonable to believe that life inevitably evolves into intelligent life if given enough time. Why some life would and some life wouldn't isn't at all clear.

> advanced species may have evolved several times but gone extinct before we could notice them.

All the potential answers to the Fermi Paradox, for sure. But it would almost definitely have to be species that never got to the "expand rapidly into other solar systems" phase.

> at any given time there's only about 1

This doesn't preclude us knowing about that 1. If it got to earth at any time in the last billion years, we might have a pretty high chance of discovering it if it existed on earth for any significant legnth of time.

It's certainly not a given that our species will ever do that or that we'll last long enough to do that.

> This doesn't preclude us knowing about that 1.

Let's say we're the 1 currently in the milky way galaxy. There could be another in the closest galaxy the Canis Major Dwarf Galaxy which is 25,000 light years away. But being able to detect a signal from 25,000 light years away... well, that's the problem. And what if they're just getting to the point where they could transmit a signal now? So maybe in 25,000 years we'd notice something... maybe? (if we're still around) As far as physically traveling 25,000 ly, well we know that even trying to go 1 ly is going to be super difficult technically. Similar problems even if there's an intelligent species on the other side of our own galaxy since it's 52K ly across.

From what we have seen on Earth, it does not seem inevitable. Dinosaurs were the largest land animals for a very long time and they did not, as far as we know, evolve towards being more intelligent. The same seems to be true for many other animal groups that have been around for a long time.

The belief that intelligent life isn't inevitable is not inconsistent with the belief that intelligent life usually will happen from any life given enough time. Why are you positioning those things as opposed? They are not.

As to why simple life would be more common than complex life... that seems obvious to me: simple systems are easier to emerge from chaos than complex ones.

Give the huge advantage that intelligence has for natural selection in complex environments, why would intelligent life not arise from simple life? It's not obvious.

That's a very limited and poor perspective. Yes, individual human cells are no more complex than others, but that doesn't encompass the entire system that has to emerge. A human being is - obviously, I would think - a far more complex system than a simple amoeba.

Maybe there are lots of earth-like planets with intelligent beings, but travel is impossible and communication is useless given the time delay.

It would cost a lot of money. It would take a very long time (hundreds of thousands of years). Nobody alive today would see the results. There are any number of systematic and non-systematic failures that could occur. building things that work autonomously for 100Kyears is nontrivial. Even if you succeeded- say, 100Kyears from now, one out of a thousand of your samples crash-lands onto a remote planet and revives- congratulations, you've maybe just contaminated an otherwise unknown ecosystem.

The story gets more interesting if earth has fusion, stable government and research funding, then you could make humans into tuns that can travel for 10K years, and have advanced propulsion (.01-.1c), pre-deliver full infrastructure...

I like to imagine there are countless planets with perfect ecosystems of living organisms where no single species dominates whole planet.

For example, with direct contact, we can estimate a probability of life along side how possible space travel is. Perhaps space travel isn't easy or fast at all and so there is plenty of life, but it is mostly stuck to its solar systems and maybe a few neighboring stars. Overall, given that we can send and receive signals much easier than we can send and receive space crafts, I think this isn't as useful a metric.

The better one is that we don't see signals from other life elsewhere, but this still has to be measured by how likely life elsewhere would be able to see our signals.

Lastly, there is the matter of what it means to be rare. Say only 2 or 3 planets in a given galaxy end up developing intelligent life, is that rare? Given the number of galaxies in the visible universe, that is hundreds of billions if not trillions of planets with intelligent life. Yet with only 2 or 3 in a galaxy, it would be easy for us to not see any signs because maybe we are the only ones in our galaxy or our galactic neighbors are on the other side of the milky way and we have no technology to communicate, nor will we for the near future. Hundreds of billions of intelligent species can be considered both rare and not rare given the sorts of scales we are talking about.

Also other edge cases, like maybe intelligent life is common enough but it tends to rarely progress past a certain point of development due to wiping itself out. Personally, every explanation I've heard or can think of has some sort of unpleasantness to it, much like the quote that says either we are alone or we aren't alone, and both ideas are scary in their own ways.

Except we have excellent knowledge about lower bounds on how easy and fast space travel can be. And its plenty fast enough to explore the entire galaxy on geological timescales. Voyager 1 is traveling at 17 km/s which would take it 1 light year every 17,700 years. Given that the galaxy is 100,000 light years across, that means that Voyager 1 could travel across the galaxy in 1.7 billion years. A spaceship built for that purpose would take vastly less time.

Voyager weighed less than 800 kg. Using the [rocket equation](https://www.omnicalculator.com/physics/ideal-rocket-equation) and a realistic exhaust velocity for methane/oxygen of 3280 m/s, you can see that you could accelerate a voyager 1 sized craft to 3000 m/s with about 1200 kg of fuel, which is less than $1 of fuel, no joke (https://www.nextbigfuture.com/2022/02/spacex-reusable-rocket...). Of course it takes a lot of money to just get that fuel into orbit: $1500/kg with a falcon heavy. But that means you could send a voyager-1-sized craft to space with the fuel it needs to achieve 3000 km/s for a mere $3 million (not including the cost of the craft itself). And harvesting methane and oxygen on smaller planets would bring down that cost by a lot.

At that speed, the craft could cross the entire galaxy in 9.6 million years. A blink of an eye on geological timescales. And if we really cared enough to spend more than a couple million dollars on this thing, we could get it there orders of magnitude faster using propulsion systems way less shitty than a methane-oxygen rocket.

With just 1% of the energy the sun outputs in a single second, you could accelerate 100 voyager 1s to 1% the speed of light.

In short, if you think space travel is a barrier, you're plainly very wrong. Even with today's technology we could send machines throughout the galaxy in a pretty short period of time. In the near future, that time will drastically reduce.

> we can send and receive signals much easier than we can send and receive space crafts

And yet there are vastly larger motivations for sending a spacecraft than sending a signal. You might not be aware that nearly all radio signals that escape the earth are not powerful enough to be detectable above noise further than 1/2 a light year out. https://astronomy.stackexchange.com/questions/33939/when-do-...

There's no reason to believe we should be able to detect alien radio signals unless they are intentionally aimed at us and meant for us. Also, you can't see a radio signal that passed by 1 million years ago. Whereas you certainly would be able to see evidence of a von neumann swarm having done that.

> Say only 2 or 3 planets in a given galaxy end up developing intelligent life, is that rare?

Whether anyone would consider that "rare" or not is irrelevant. The puzzle would be: if even ONE intelligent speicies existed out there more than several million years ago, why haven't we seen evidence of their space craft?

> maybe intelligent life is common enough but it tends to rarely progress past a certain point of development due to wiping itself out

Yes, this is of course the premise of usual solutions to the fermi paradox. However, those solutions are often either "maybe nukes will destroy us" or "maybe something we don't know about yet will". Neither are super satisfactory as answers.

Haven't we been? When I look all around, the whole place is simply crawling with self-replicating machines and some of them even got to a point of making first attempts to leave this planet to infect a new one.

Particle Life Emerges from Simplicity - https://news.ycombinator.com/item?id=34156592 - Dec 2022 (1 comment)

Particle Life Simulation - https://news.ycombinator.com/item?id=33680845 - Nov 2022 (1 comment)

Particle Life - https://news.ycombinator.com/item?id=21875720 - Dec 2019 (7 comments)

https://github.com/jasonjmcghee/compute-shaders

I had a similar concept in mind when I started experimenting in 3D with what I now call "Altphy" (alternative physics), but I've not been able to really make it work as intended (really, is far from working). Also probably the logic and idea behind it too much for real time processing. I'm sharing it only because maybe pieces of that code (or the idea itself) can progress into something one day.

source: https://github.com/aDeveloperCase/altphy

Also, it seems like in this system the speed of light is infinite, since every particle acts on every other particle each frame, regardless of distance. In CGoL there is a speed of light, since cells can only influence their immediate neighbors each frame.

https://www.youtube.com/watch?v=BpN-DE3o6u8

https://bingdev.binghamton.edu/sayama/SwarmChemistry/

The particles form semi-stable rotating rings until they get too close to another ring. It's quite fascinating to watch. Messing with the viscosity changes the stability and radius of the rings

But the thing is it does not demonstrate that complexity can come from simplicity. To make a 'life' there are 8 parameters to be modified across a range and 'fine tuned' to get some tangible stable complex structure, all to be done by already conscious beings ( Users anyone? ). So much for simplicity

you can run it with: cargo run --release

No input yet, just randomly initialises params each run. But it runs with 4000 particles on my machine.

Found some info here, seems like these are open questions [1].

--

1: https://en.wikipedia.org/wiki/Artificial_life#Philosophy

https://github.com/derekburgess/simcraft

Rotting is caused by living organisms. Being eaten is caused by living organisms. Disease is caused by living organisms.

They could not die until death evolved. They could be physically destroyed but that’s not that likely.

In this demonstration, particles with certain rules can interact in such a way that self-organizing structures emerge.

Is there reproduction? Is there evolution? Is there death? It appears not. Those are essential to life.