Reading through this book a bit I found a mention of penrose block replicators, and through that found this video from the early 60s. Not really a replicator in an real sense, but still a neat demonstration: https://youtu.be/hQ6T_TY3JA4
Has anyone tried evolving small shaped block to self assemble when you shake them together? I'm thinking of SLA 3D printing the shapes in various materials to create a functional component by simply shaking everything together.
I would argue that a self-replicating machine could be a slight modification of this idea. Print some blocks and put them in a container and shake them. Then come up with some structure, made up of these blocks, that will cause a copy of itself to emerge when shaking, that would have never or extremely rarely occurred if the parent structure had not been present.
I guess it depends on your definition. I can think of many examples that are self replicating in some sense, but probably not in the same way as a bacterium.
A 19th century machine shop is probably capable of self-replicating, with metal as an input and a human 'catalyst'.
This was published in 2004 and was highly speculative at the time. We are still a long, long way from the Diamond Age fantasy of self assembling nanotech.
Recent work in this area seems to mostly involve modding 3D printers to try and integrate conductive materials (basic circuits) into plastic structures.
What do you define as an "artificial physical self-replicating machine"?
A genetically engineered bacterium is a self-replicating machine created via artificial means that exists to effect some purpose in the physical world.
No, it's never been done.* While factories are built all the time, they have never been built entirely from their own products and without human labor as an essential ingredient (a "closed" manufacturing process).
There's an economic reason for this: the constraints that make a factory "self-replicating" mostly make things more difficult/expensive; they're only beneficial when operating in a human-hostile area disconnected from existing supply chains, so it's always been better to use open-loop factories + human labor to make products quicker, cheaper, and of higher quality than a self-replicator would. Space industrialization is where self-replicators will be exceptionally useful.
These are the key functions of a truly closed-loop self-replicating factory:
1. collect energy
2. use energy to collect matter.
3. use energy and matter to create parts.
4. use energy to assemble parts.
For example, consider a water-powered saw mill, made of wood with some metal "vitamins":
1. Wooden water wheels collect energy from flowing rivers.
2. Humans use wood/metal saws to cut trees, and wooden rollers/sleds and transport them to the mill.
3. The mill's saws, drills, and lathes turn the tree trunks into useful wooden parts.
4. Humans move wood parts from station to station in the mill and can assemble another mill from the boards, dowels, and a few metal saw blade/drill bit "vitamins."
Could you replace the humans with logging robots, and use robot arms to move things inside the mill? Sure, but humans are so much better suited for these tasks, and now your humble saw mill has to be able to create, power, and control these robots in order to be closed-loop.
*Yes clever HN, you can get all pedantic about biological self-replicators, self-assemblers, and nano-bots, but you're just muddying the waters. We haven't ever managed a von Neumann-style "clanking automaton" self-replicator.
P.S. don't worry about rampancy—there are physical limits that make sci-fi's Grey Goo floods impossible.
This is taking a naturally occurring bacteria, and modifying it slightly. We are using the bacteria's existing protein production infrastructure to produce a peptide hormone.
It is, in some sense, a programmable robot arm that assembles structures from parts.
As we have gotten better at understanding how these mechanisms work, we can tweak things further. We can imagine many directions for this to go in. Not just producing proteins with existing amino acids, but having the bacteria produce new ones with interesting properties.
We could eventually be able to produce a wide array of chemicals, and not just organic compounds. Though the range of things that can be produced is still limited.
The main thrust of molecular nanotechnology is to leave behind the protein synthesis that biological life uses, and instead be able to produce arbitrary structures from arbitrary atoms.
This is a difficult and ambitious goal, but one that is imminently achievable.
I have three of them at home. They're easy to make but relatively high maintenance. Because of this, I try to make sure that they learn self-maintenance before self-replication. Let's see how that plays out.
Agreed on humans, though I wonder where is the line between artificial and natural life? Large portion of genome modified? Synthetic cells? Synthetic cells without any natural cellular components?
I've been thinking about self-replication for several years. You basically need a robot arm, a small foundery, the spining part of a lathe, a rolling mill to make metal sheet and copper cable. Some way to coat the copper cable (Don't remember) You can use the foundery to produce silicon carbide and graphite. You need a 2d motion system to move the robot arm (maybe 2). You need a system to expend the volume of the machine so that a machine can give birth to another machine. You can bootstrap from that. Initialy photolithography will not be include since you can buy something similar to a rasberry pi for like 2 $. Eventually the more you bootstrap you can create self-replicating factory like machines that can output entire cars from input code.
To fetch the raw materials you should use a form of symbiosis. I assume the raw materials are iron, silicon, carbon, copper, (Rasberry pi lol)
Just contact me If you got time/money to do that I will give you 3d sketches.
Also there is another process you might want to implement if you want to make solar panels. Personally I would just plug it on the grid (for earth based usage)
After that its mostly a job of good programming you want the part you created without new processes (ex: photolithography) to still work after the bootstrap process.
This is something that explores current things (3d printers, CNC plywood cutters, etc) that could gradually play larger and larger roles in the fabrication of identical -- or better yet, identical with improvements -- copies of themselves. https://www.youtube.com/watch?v=l4tYIX_QJ2Q
This will most certainly happen gradually, and will probably involve a whole cluster of machines. For instance, a robot arm, a 3d printer, and a bunch of jigs and other devices, which together can make parts of themselves or play a role in assembly.
Here's an honest question that I've pondered occasionally, without really spending the time to research an answer. Not sure if this is biology, chemistry, etc, but would appreciate any insights HN readers may have:
How did replication develop in nature? Granted some cells popped into existence as some point, do we have any insights into when/how cell replication became a thing?
Somewhere in between would be self-catalyzing chemical reactions. It's not that hard to imagine how such things could eventually evolve into what we call "life", with no clear line between non-living and living.
Exactly! One aspect to remember is that once you have a self—replicating mechanism, by the nature of it, the replicating parts are becoming more widespread. In other words, small effects with larg, self—reinforcing consequences.
